rHE FOOD VALUE OF SEA MUSSELS 
 
 From BULLETIN OF THE BUREAU OF FISHERIES, Volume XXIX, 1909 
 
 Document No. 742 : : : : : : : : : : : : : Issued February 24, jgii 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 
 1911 
 
aass_i_l_l2- 
 
 Book 
 
 i^S 
 
^ 
 
 THE FOOD VALUE OF SEA MUSSELS 
 
 From BULLETIN OF THE BUREAU OF FISHERIES, Volume XXIX, 1909 
 
 Document No. 742 : : : : : : : : .- .- .- .• .• Issued Fehru 
 
 ary 24, igii 
 
 
 WASHINGTON 
 
 GOVERNMENT PRINTING OFFICE 
 
 1911 
 

 A 
 
THE FOOD VALUE OF SEA MUSSELS 
 
 By Irving A. Field 
 U. S. Fisheries Laboratory, Woods Hole, Mass. 
 
 85 
 
CONTENTS. 
 
 J- 
 
 Page. 
 
 Introduction 87 
 
 Natural history of the sea mussel 87 
 
 Form and structure 87 
 
 Reproduction 89 
 
 Growth 92 
 
 Food 92 
 
 Enemies and parasites 95 
 
 Distribution and habitat 97 
 
 Present uses of sea mussels 97 
 
 Sea mussels as food 99 
 
 Palatability 100 
 
 Digestibility 100 
 
 Experiments to show available protein loi 
 
 Metabolism experiments 102 
 
 Composition and nutritive value 105 
 
 Mussels a cheap food no 
 
 Preservation methods in 
 
 Canning in 
 
 Pickling 113 
 
 Drying 114 
 
 Cold storage 116 
 
 Recipes for cooking 116 
 
 Cultivation of mussels 1 19 
 
 Poisonous mussels 123 
 
 Summary, conclusions, and recommendations 125 
 
 Literature 126 
 
 86 
 
Bui.1.. U. S. B. F., 1909. 
 
 Platk XVIII. 
 
 il/i///«ie,/«//.vI.iinKciis 
 
 2. — A bed of sea-mussels i year old. 
 
THE FOOD VALUE OF SEA MUSSELS. 
 
 J' 
 
 By IRVING A. FIELD. 
 IJ . S. Fisheries Laboratory, Woods Hole, Mass. 
 
 J' 
 
 INTRODUCTION. 
 
 The purpose of this report is to make known the character and food value of one of 
 our abundant, nutritious, and palatable sea products which has been little utilized up 
 to the present time. The substance of a previous paper on the subject '^ is here added 
 to and amplified into a more complete, and, it is hoped, more useful discussion. 
 
 The sea mussel has been, so far as most of this country is concerned, in the category 
 of many other unappreciated resources which have later become valuable. Familiar 
 examples are the sturgeon and the eel. Finnan haddie, too, have only recently come 
 into popular favor. The large snail, or abalone, of the California coast, at first eaten 
 only by the Chinese, is now relished by the American palate. Raising frogs for market 
 is now a profitable industry in various parts of the United States, although in 1903 
 a bill introduced into the Pennsylvania legislature for the protection of frogs was 
 greeted with shouts of laughter. The mussel bids fair to become as valuable as any 
 of these products, for its merits are unquestionable, once the groundless prejudice shall 
 have given way. 
 
 The basis of this report is a series of investigations carried on during three summers 
 for the United States Bureau of Fisheries at its laboratory at Woods Hole, Mass. 
 
 NATURAL HISTORY OF THE SEA MUSSEL. 
 
 FORM AND STRUCTURE. 
 
 The common sea mussel, Mytilus edulis (pi. xviii, fig. i), along with the oyster and 
 clam, is a member of the class Lamellibranchia in the phylum Mollusca. In form it is 
 triangular ovate. The umbo or beak is much pointed and is situated at the anterior end 
 of the valves (pi. xix, fig. 3). In size it measures from 2 to 4 inches in length and from 
 I to i}4 inches in diameter. Occasionally specimens 4^ inches long are found. The 
 color of the shell proper varies from violet to pale blue. Externally it is covered with 
 a horny epidermis of shining blue-black. The sea mussel is most apt to be confused 
 
 o Field, I. A: Sea mussels and dogfish as food. Proceedings Fourth International Fishery Congress, Bulletin U. S 
 Bureau of Fisheries, vol. xxviii, 1908, p. 241-257. 
 
 87 
 
8S BULLETIN OF THE BUREAU OF FISHERIES. 
 
 with the horse mussel, Modiola modiola, which it most closely resembles. Close obser- 
 vation, however, will show that the umbo or beak of the horse mussel is not at the 
 extreme end of the shell, but a short distance back near one margin, and that the 
 epidermis is brown instead of blue. 
 
 Internally, the most conspicuous part of the body is the mantle (pi. xix, fig. 3 and 4) , 
 which is made up of two lobes, each attached to and filling one of the two valves of the 
 shell. Just before breeding, the mantles are thick and fleshy and assume a characteristic 
 color by means of which it is possible, in a general way, to distinguish the two sexes. 
 The males are white or pink, while the females vary from an orange to a brick red 
 color. Another means of distinguishing the sexes is to note the surface character of 
 the mantles, which in males shows closely aggregated follicles filled with spermatozoa 
 (pi. XIX, fig. i); in the females it presents a uniform granular appearance containing 
 scattered groups of pigment cells (pi. xix, fig. 2). During the quiescent period the 
 mantles are thin and almost transparent. 
 
 The foot (pi. XIX, fig. 3), so well marked in the fresh-water mussel, is a muscular 
 organ of small size in the sea mussel, tongue-like in form, with a longitudinal groove 
 on the underside. Its hinder portion contains the byssus gland, which secretes the 
 byssus or "beard" for the attachment of the mollusk (pi. xix, fig. 3). 
 
 There are three important sets of muscles in addition to those in the foot, (i) The 
 adductors (pi. xix, fig. 3) are two in number. They extend across from one valve to the 
 other and serve for closing the shell. The posterior adductor is the large muscle which 
 it is necessary to cut before the shell is opened. The anterior adductor is inconspicuous 
 and lo<;ated, as its name implies, at the front end of the shell. (2) The retractors (pi. xix, 
 fig. 3), which are two in number and serve for withdrawing the foot, are long, narrow, 
 paired muscles attached to the foot, from which one pair extends forward and the other 
 backward to attach to the shell. (3) The pallial muscles (pi. xix, fig. 3) are a row of 
 delicate structures along the border of the mantle which serve to attach it to the shell. 
 
 The digestive tract has a complicated arrangement. It consists of a large mouth 
 (pi. XIX, fig. 3) located at the anterior end just in front of the foot, a short gullet opening 
 into a stomach which is surrounded by a large, dark-colored digestive gland, sometimes 
 called the liver (pi. xix, fig. 4). From the posterior end of the stomach the intestine 
 passes backward to the posterior adductor muscle, where it turns forward in an oblique 
 manner to the left side of the stomach. At this point it turns back again and passes 
 through the ventricle of the heart and over the posterior adductor muscle to the anus, 
 which is a short distance behind this muscle. The labial palps (pi. xix, fig. 3), two pairs 
 of loose flaps which lie just inside the edge of the mantle attached to the lower lip of 
 the mouth, may be considered as accessory structures of the digestive system. They 
 are covered with cilia and serve to direct food to the mouth. 
 
 The gills (pi. XIX, fig. 3) are a pair of filamentous structures extending along each 
 side of the body from between the inner and outer palps to the posterior end of the 
 animal. In cross section they present the form of a narrow W attached by the central 
 part of the letter; the outer and inner arms remain free at their upper ends. 
 
FOOD VAI,UE OF SEA MUSSEI.S. 89 
 
 The kidneys, or so-called organ of Bojanus, consist of two symmetrical sacs on the 
 ventral side of the body situated one on either side of the foot. Each extends backward 
 to its opening, which is located on the inner side of the point of attachment of the gill 
 just anterior to the posterior adductor muscle. 
 
 The circulatory system is well developed and completely closed as in all other 
 mollusks. The heart lies in the mid-dorsal region in a pericardial chamber. From the 
 heart a single large blood vessel is given off, which passes forward as the anterior aorta. 
 It breaks up into a network of arteries that ramify all through the body. The blood is 
 collected into a large, longitudinal vein on the ventral side of the body, from whence it 
 passes through the kidneys to the gills and finally to the heart. The blood is colorless. 
 
 The nervous system, as in other lamellibranchs, is made up of three pairs of gang- 
 lionic centers connected one with the other and giving off nerves to supply the various 
 surrounding organs. One pair is located in the head region with a ganglion on each 
 side of the gullet, another in the foot, while the third, just ventral to the anterior edge 
 of the posterior adductor muscle, supplies the digestive and reproductive organs, heart, 
 gills, and posterior portion of the mantle. 
 
 The reproductive system is much more extensive than is found in most other mol- 
 lusks. It is made up of a complicated branching network of canals which radiate 
 throughout nearly the entire body. Internally each canal ends in a pocket or fol- 
 licle. Externally the canals open out on either side of the body through a genital 
 papilla which is at the inner point of attachment of the gills in front of the posterior 
 adductor muscle and just in front of the kidney opening (pi. xix, fig. 4). Since there is 
 no definite organ which can be designated as an ovary or testis, it is impossible during 
 the quiescent period to determine the sex of an individual. In mussels from Woods 
 Hole, Mass., genital products were found developing in these canals during the early 
 spring and summer months. (Compare fig. 1-4, pi. xxiii). According to Williamson 
 (1907) the eggs arise from certain minute, brown-colored cells which he found present 
 in the mantle of the female. My own observations are to the effect that the sexual 
 products are formed by a process of budding from the cells lining the walls of the genital 
 canals. At first the cells formed are extremely small and undergo rapid division. 
 After a time division stops and the cells enter upon a period of growth. By the time 
 the sperms and eggs are ripe they occupy almost the entire portion of the mantles, which 
 are greatly distended by them. They fill the floor of the pericardial region, the wedge- 
 shaped abdomen and cover to greater or less degree the outer walls of the digestive gland 
 (pi. XIX, fig. 3). 
 
 REPRODUCTION. 
 
 With such an extensive genital system the mussel is capable of producing an 
 enormous number of germ cells. For the past two summers between 200 and 300 
 mussels were kept in a shallow trough of running sea water where the process of egg 
 laying and fertilization could be readily observed. The extrusion of the sexual elements 
 on the part of two or three individuals began within an hour after bringing them in 
 from the natural beds, and as time passed the number of spawning individuals 
 
90 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 increased. After from twenty-four to thirty-six hours all the ripe mussels of a given 
 lot were spawned out. It was observed that spawning started soonest among specimens 
 which had been roughly handled before being placed in the trough. The duration of 
 spawning varied with different individuals. Some would deposit practically all their 
 products at one time, which required from twenty minutes to an hour. Others would 
 spawn intermittently for short periods of several minutes each and finally stop altogether 
 without having discharged half their genital products. 
 
 A male mussel discharges a stream of milt which will color the water for a distance 
 of ID or 12 feet before becoming too diffuse to be seen. In quiet water a female mussel 
 will discharge her eggs so that they will fall in a heap. They can easily be removed 
 by means of a pipette and measured in a graduate, a method which revealed the fact 
 that mussels lay from i to 4 cubic centimeters of eggs at a single spawning. Knowing 
 the average diameter of the eggs to be 0.07 mm., it is easy to calculate the number in a 
 cubic centimeter, which approximates more than 3,000,000. On August 2, 1909, a 
 mussel 3X inches long was seen to begin the deposition of eggs. A homeopathic vial 
 of about 10 c. c. capacity was immediately placed in such a position as to receive the 
 string of spawn as it was discharged. The egg laying proceeded at a remarkably rapid 
 rate and continued for 15 minutes, when it suddenly stopped. 
 
 The mussel was watched for an hour longer and, when it was seen that no more 
 eggs were to be laid, was removed from the trough and the shells opened to expose the 
 mantle. The condition found is shown in figure 4 of plate xix. All of the eggs except 
 little patches here and there near the edge of the mantle had been discharged. Of 
 course it was not known whether any of the eggs had been laid before this individual 
 had come under my observation. The number of eggs laid measured 4 c. c, which 
 means that this mussel liberated in round numbers about 12,000,000 eggs in 15 minutes. 
 This is possibly more than the number usually produced. Three other mussels under 
 my observation liberated from 6,000,000 to 9,000,000 each. 
 
 The period of reproduction varies for different regions and is influenced considerably 
 by climatic conditions. It has been hard to determine when the mussel breeds on our 
 northern Atlantic coast. Verrill and Smith (1873) and Goode (1887) say that the 
 mussel breeds early in the spring. Ganong (1889), writing in Acadia, states that the 
 height of the breeding season appears to be April and May. Mr. Charles H. Silverwood, 
 of Pawtucket, R. I., who for years has been watching the habits of the mussels in 
 Narragansett Bay, writes that the breeding season varies with the weather, beginning 
 sometimes as early as the middle of June and lasting until late in August. Mr. George A. 
 Carman, of Canarsie, N. Y., observes that the mussels in Long Island Sound spawn 
 during April and May, while those in the open ocean do not spawn until about Sep- 
 tember I. My own observations on the development of the sexual organs in mussels 
 from Woods Hole, Mass., are in harmony with Silverwood's statement. Specimens of 
 mussels were collected every month from February 7 until August 24. The mantles were 
 sectioned and mounted for microscopical examination. The series of preparations 
 show a gradual development of the sex cells during the whole period. No mature 
 
FOOD VAI.UE OF SEA MUSSELS. 9 1 
 
 sexual products were observed before July 3. On that date I found spermatozoa, 
 which, when placed in sea water, were very active; they clustered about the eggs and 
 by their active movements caused the eggs to slide gradually hither and thither across 
 the microscopic field. 
 
 In England, on the Lancashire coast, Scott (1901) found that the mussels do not 
 breed until midsummer. He kept the mussels in tanks under constant observation 
 for a year and made frequent comparisons with those in natural beds. The sex organs 
 developed at about the same rate in the two lots. The first eggs were discharged on 
 May 6 by individuals in both the tanks and the beds. No spermatozoa, however, were 
 observed until June 13 and the first developing eggs were found on June 14. The spawn- 
 ing season continued up to the middle of July. In France, where the water is much 
 warmer than on our coast, the mussel spat appears in February and March. It is clear 
 from the above evidence that the mussel breeds at various times between the months 
 of February and September according to the temperature of the water in which it lives. 
 
 The ripe egg is a spherical body so small as to be hardly visible to the naked eye. 
 It is surrounded by distinct membrane. On account of the great number of opaque 
 yolk granules "which fill the egg, none of its internal structures, such as the nucleus 
 and nucleolus, are clearly visible under the microscope. The spermatozoa are pin shaped, 
 with a conical protuberance upon the head. When liberated in the water they swim about 
 actively and show great tenacity of life. Specimens placed in a bowl of sea water kept 
 up active movements for more than six hours. 
 
 It has been an open question whether fertilization of the eggs takes place within the 
 body of the female or not. MTntosh (1885) and Wilson (1886) believe that it is accom- 
 plished outside of the female. That this is possibly so, Wilson has demonstrated by mix- 
 ing ripe ova and spermatozoa in a beaker of sea water. He obtained the sexual products 
 by mincing up portions of the mantle of the two sexes. Scott (1901), who studied the 
 mussels kept in tanks, believes, on the other hand, that fertilization of the eggs takes place 
 in the branchial chamber of the mother. He observed that "the embryos flow from the 
 female in a slow, distinct stream." If the water is quiet, they settle on the bottom, 
 forming a pinkish mass. In this position they continue to develop for from eight to 
 twelve hours, finally becoming ciliated larvae, which rise to the surface and swim about. 
 At this time they are borne hither and thither by the tidal currents for about four days, 
 so that eventually they reach almost every yard of our coast line within their range. At 
 the end of this period the larvae undergo important changes. They develop a shell and 
 settle upon seaweeds, hydroids, or other convenient objects for attachment. At this stage 
 they vary from -^^ to ^^ of an inch in diameter. The foot now becomes the chief organ 
 of locomotion. By means of it they can creep from unfavorable situations over seaweeds 
 and other objects to a more suitable position. In young forms the foot is capable of 
 great extension and has the appearance of a long, white, flexible thread. By extending, 
 attaching, and contracting this foot, the mussel readily draws itself forward. Of the 
 myriads of brood mussels that appear shortly after the breeding season, only a small 
 portion ever reach suitable places for growth, and of these only a few are destined to 
 reach maturity. 
 
 59730°— II 2 
 
92 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 GROWTH. 
 
 The rate of growth is dependent upon circumstances of situation, temperature, 
 salinity of the water, and the amount of food available. Mussels in sheltered positions 
 grow more rapidly than those exposed to the force of waves. The ideal location for the 
 mussel is an estuary where food is supplied in great abundance, where the exposure to air 
 between tides is not long, and where there is no deposition of silt. In such a place, if not 
 too thickly crowded, they may grow to the average size of 2 or 3 inches in length in a single 
 year. On the English coast, where they are cultivated by the bed system, it requires not 
 less than two years and usually three years for them to reach a length of 2 inches. In 
 France, where they are cultivated by the buchot method, that size is acquired in about 
 a year and a half. On our Atlantic coast Charles H. Silverwood, of Pawtucket, R. I., 
 says the mussels of Narragansett Bay reach marketable size, which I take to be not less 
 than 2 inches, in from twenty-eight to thirty-four months. 
 
 Overcrowding is a very important factor affecting the growth of mussels. A single 
 pair produces myriads of young, most of which are doomed to early death through lack 
 of space and other conditions necessary to growth. After the free swimming stage is 
 over, the young mussels often apply themselves in such close proximity to each other 
 that no space is left for increase in size. In order to grow it is necessary for the stronger 
 to smother out the weaker competitors. Sometimes the death rate from this cause is so 
 high that the many disintegrating bodies apparently contaminate the closely applied 
 living individuals and cause their destruction. This process may go on so far as practi- 
 cally to destroy what looks like a promising bed. Mussels on the margin of a thick 
 cluster will almost always be found larger and in a more thrifty condition. Consequently, 
 the healthiest individuals and specimens of largest size, other conditions being the same; 
 are found in beds where the mussels do not lie in close contact with each other. 
 
 The food of the mussel is an important topic for study. A knowledge of the food and 
 feeding habits of the marine animals which are utihzed as food by man is of much greater 
 importance than is ordinarily supposed. Especially is this true of forms like the mussel 
 and oyster, which may be propagated by artificial means. The agriculturist who plants 
 his grain regardless of the presence or absence of nitrates, phosphates, and sulphates in 
 the soil is apt to reap very small crops. These chemical substances constitute an 
 essential part of the food of plants, and the amount of the harvest's yield depends 
 largely upon their presence in the ground on which it grows. The important relation 
 of soil composition to crop production is well known and is receiving very serious 
 investigation in every State of the Union. 
 
 The cultivation of marine products depends upon this same principle. The would-be 
 oyster culturist who plants his seed oysters in any convenient spot, without knowledge of 
 what constitutes their food or of its presence in the water, will be even less successful than 
 
FOOD VAI^UE OF SEA MUSSEI.S. 93 
 
 the farmer who ignores the first principles of agriculture. Up to the present time, 
 however, very little study has been made of the food of marine animals or of the relative 
 fertility of the waters in various parts of the sea. Such investigations as those of Peck 
 (1894 and 1896) on the sources of marine food, and of Moore (1907) on the food of the 
 oyster are of very great economic value. 
 
 My observations on the food of the mussel were necessarily limited. They were con- 
 fined to the vicinity of Woods Hole and to the months of July and August. Lack of 
 time did not permit a determination of the food value of the water over the mussel beds. 
 During the summers of 1908 and 1909, however, a microscopic examination was made of 
 the material found in the digestive tracts of 50 mussels. 
 
 Two methods were employed. The first was to extract the stomach contents by 
 means of a pipette, which was thrust down the animal's gullet. The substance drawn 
 out from the stomach was mixed with a few drops of water and a thin layer spread 
 across the middle of a microscopic slide. The slide was then passed several times 
 through the flame of an alcohol lamp, until the organisms were thoroughly fixed by the 
 heat and the water almost evaporated to dryness. A drop of glycerin or of hot glycerin 
 jelly was next applied and a cover glass pressed down upon it. Permanent mounts 
 were later made from these preparations by cleaning the slides outside the boundary 
 of the cover glass and ringing the mounts first with King's cement and, twenty-four 
 hours later, ringing them again with asphaltum. This method proved best for pre- 
 serving the animal forms. Protozoa, found in the stomach. 
 
 The second method was to place the mussels, immediately after removal from their 
 natural beds, in small dishes of filtered sea water. After two or three hours' time the 
 bottoms of the dishes were covered with intestinal discharges, which were removed by 
 means of a pipette and transferred to a vial containing 95 per cent alcohol. After the 
 sediment had completely settled the alcohol was drawn off and fresh alcohol added. 
 The process was repeated, using absolute alcohol instead of the weaker grade. This 
 was followed by a few minutes' treatment with xylol, and after removing most of the 
 xylol three or four drops of a rather thin solution of Canada balsam were added. This 
 mixture was allowed to stand for a few hours, until the xylol, sediment, and balsam were 
 thoroughly mixed. Then, by means of a pipette, a large drop was transferred to a 
 microscopic slide and on it was placed a cover glass. This method was found best for 
 the preservation of the plant organisms which are known as diatoms. The diatoms, 
 thus prepared, have had the pigments and coagulated protoplasm more or less com- 
 pletely removed, leaving a clear view of the striations and other markings on the 
 skeleton. 
 
 The food of the mussel was found to consist of microscopic plants and animals which 
 are carried by chance to the mollusk by water currents and are swept into the mouth 
 by means of cilia on the gills and palps. The wall of the gullet is also lined with cilia, 
 which direct the movement of the food material into the stomach. Not only food, but 
 dirt and other indigestible substances are swept in. From the alimentary tracts of 50 
 
94 BUIvIvETlN OF THE BUREAU OF FISHERIES. 
 
 mussels there were found 29 species of diatoms and 9 species of Protozoa.** The relative 
 abundance of each species is indicated in the following list : 
 
 Organisms Constituting the Food ok the Mussel. 
 
 DiATOMACE.^. [Plates XX and xxi.] 
 
 Actinoptychus undulatus Ehrenberg (fig. 12) Common. 
 
 Amphiprora lepidoptera Cleve Very common. 
 
 Amphora proteus Gregory (fig. 2) Frequent. 
 
 Biddulphia favus (Ehrenberg) H. V. H. (fig. 11) Do. 
 
 Biddulphia rhombus (Ehrenberg) W. Smith (fig. 1) Do. 
 
 Coscinodiscus excentricus Ehrenberg (fig. 25) Do. 
 
 Grammatophora marina Kiitzing (fig. 16) Do. 
 
 Hyalodiscus subtilis Bailey (fig. 23) . .Very common. 
 
 Melosira sculpta Kiitzing (fig. 14) Do. 
 
 Navicula didyma Ehrenberg (fig. 6) Common. 
 
 Navicula lyra Ehrenberg (fig. 8) Occasional. 
 
 Navicula lanceolata Kiitzing (fig. 7) Frequent. 
 
 Navicula splendida var. puella Ad. Schmitz (fig. 10) Occasional. 
 
 Nitzschia sigma Grunow (fig. 15) Common. 
 
 Nitzschia sigma var. rigida Grunow Do. 
 
 Nitzschia sigma var. sigmatella Grunow (fig. 13) Do. 
 
 Pleurosigma afline Grunow Frequent. 
 
 Pleurosigma angulatum W. Smith (fig. 24) Do. 
 
 Pleurosigma balticum W. Smith (fig. 18) Common. 
 
 Pleurosigma decorum W. Smith (fig. 20) Do. 
 
 Pleurosigma elongatum W Smith (fig. 19) Do. 
 
 Pleurosigma naviculaceum Brebisson Very common. 
 
 Rhabdonema adriaticum Kiitzing (fig. 5) Frequent. 
 
 Rhabdonema arcuatum Kiitzing (fig. 9) Do. 
 
 Rhizoselenia setigera Brighter (fig. 17) Very common 
 
 Stephanopyxis appendiculata Ehrenberg (fig. 21) Occasional. 
 
 Surirella ovalis var. ovata Brebisson (fig. 4) Common. 
 
 Synedra gallionii Ehrenberg (fig. 22) Very common. 
 
 Tabellaria fenestrata Kiitzing (fig. 3) Frequent. 
 
 PROTOZOA. [Plate xxii.] 
 
 Ceratium f usus Ehrenberg (fig. 3) Frequent. 
 
 Distephanus speculum Stohr (fig. 4) Common. 
 
 Exuviaella lima Ehrenberg (fig. 5) Very common. 
 
 Exuviaella marina Cienkowsky (fig. 1) Common. 
 
 Glenodinium compressa Calkins (fig. 2) Do. 
 
 Peridinium divergens Ehrenberg (fig. 6) Do. 
 
 Prorocentrum micans Ehrenberg (fig. 7) Very common 
 
 Tintinnopsis beroidea Stein (fig. 9) Do. 
 
 Tintinnopsis davidoffi Daday (fig. 8) Common. 
 
 oThe identifications were made by Mr. T. E. B. Pope, assistant of the Bureau of Fisheries. 
 
FOOD VAIvUE OF SEA MUSSEI.S. 95 
 
 The organisms included in this Hst are of the most primitive type, and, as Peck 
 (1896) has demonstrated, are the ultimate source of food for all marine animals. The 
 food of diatoms is the dissolved mineral matter removed from the soil and carried by 
 rivers and the smaller streams down to the sea. It is absorbed through the surface 
 of their bodies and transformed into living tissue. When their bodies have increased 
 to a certain size, each individual divides into 2 ; as these grow they divide into 4, the 4 
 into 8, 8 into 16, etc., in geometric ratio. Under favorable conditions multiplication 
 by this means is so rapid that millions may be produced in a day from a single individual. 
 The Protozoa on which the mussel feeds multiply in much the same way, but in feeding 
 habits dififer from the diatoms in that they consume solid food, chiefly diatoms, in 
 addition to absorbing soluble nourishment through the surface of the body. It is 
 interesting to note, as Professor Brooks has pointed out, that these unicellular organ- 
 isms are the means of bringing back to us in the form of food our mineral wealth which 
 is continually being lost through the agency of erosion and solution. 
 
 ENEMIES AND PARASITES. 
 
 The enemies of the mussel are numerous. Killifish, cunners, and scup are very fond 
 of the young mussels, greedily stripping them from the wharf piles, seaweeds, and other 
 objects of attachment. The squeteague and tautog eat them from the beds. Among 
 the mollusks the drill, Urosalpinx cinereus, destroys large numbers by boring a hole 
 through the shell to the soft parts on which it feeds. On nearly every mussel bed 
 numbers of shells may be found pierced with a hole about the size of a pin head which 
 testify to the ravages of this voracious snail. Another snail, Neverita duplicata, is 
 supposed to feed upon them in the same manner but the hole drilled is much larger. 
 The so-called whelks, Busycon canaliculata and B. carica, also prey upon them to 
 considerable extent. Perhaps the worst enemy is the starfish, which destroys them to 
 as great a degree as it does the oyster. In England, Lebour (1907) reports that one 
 whole bed of mussels at the mouth of the River Tyne was completely destroyed by 
 this echinoderm. Crows and rats are said sometimes to eat mussels from the beds when 
 they are exposed. Seaweeds like Ulva and eel grass (Zostera marina) are very injurious 
 to the health and growth of mussels when they spread over the beds. Two of the largest 
 beds near Woods Hole, Mass., have been practically ruined this year (1908) by a dense 
 mass of eel grass which has sprung up over them. The weed by its growth not only 
 gradually smothers the mussels, but causes the sand and mud to silt over them at such 
 a rate that in a few months all signs of the bed are obliterated. The decaying bodies 
 of the shellfish fertilize the soil and finally what was once a bed of mussels is a thrifty 
 bed of eel grass. 
 
 The parasites of the mussel are few. The most common one is a little crab, Pinno- 
 theres maculatum, which is very similar to the oyster crab but larger and with a tougher 
 shell. It apparently works no injury to either the health or growth of the shellfish. 
 Indeed, some observers believe the relation is symbiotic rather than parasitic. The 
 
96 BULI.ETIN OF THE BUREAU OF FISHERIES. 
 
 crab lives in the gill chamber, where it is protected from outside harm. In return for 
 this protection it is said that the crab runs out and collects food which on returning it 
 chews up in the gill chamber and shares with its host. From the examination of the 
 stomach contents of several of these crabs, however, I found no evidence to support this 
 belief. The only food material found consisted of diatoms and other microscopic 
 organisms which probably would have been utilized by the mussel had not the parasite 
 been present. Other hosts, such as the giant scallop and smooth scallop, are known to 
 harbor this same species of crab. In describing it (Goode, 1884), Rathbun says: 
 
 Another species of Pinnotheres (P. maculatum) frequently occurs in the shells of the common sea 
 mussel {Mytilus edulis) and the smooth scallop {Pecten tenuico status), between the gills of the animal. 
 It attains a size larger than the oyster crab, and, as in the case of the latter, the females alone are para- 
 sitic, the males only having been found swimming at the surface of the sea. We have never heard of this 
 species being eaten, probably because neither the mussel nor the smooth scallop has ever been used as 
 food in this country. In the summer of 1880, while dredging off Newport, R. I., the United States 
 Fish Commission steamer Fish Hawk came upon extensive beds of the smooth scallop, from a bushel 
 of which nearly a pint of these crabs were obtained. Again, in 1881, the same species was encountered 
 in great abundance by the same party in Vineyard Sound, in Mytilus edulis. As an experiment, they 
 were oooked along with the mussels and found to be very palatable, although their shell is, perhaps, 
 somewhat harder than that of Pinnotheres ostreum. 
 
 In my own experience with mussels I have observed no other parasite, but in 
 Europe Lebour (1907) found a boring annelid, Polydora ciliata, which attacks the 
 Northumberland mussels. The worm burrows through the shell from the outside, 
 making a hole about the size of a pin. It causes the mussel to grow pearly excresences, 
 often to considerable extent, over the internal surface of the shell, which interfere with 
 the muscular development of the animal and frequently almost destroys the posterior 
 adductor muscle. If the pearly masses press upon the mantle, the reproductive lobes 
 fail to develop in such places. Aside from injuring the mussel, the presence of the 
 pearly excrescences gives the mussel an unsightly appearance and consequently renders 
 it unfit for market. 
 
 Three larval trematodes are also found in the Northumberland mussels. The 
 cercarias of the pearl trematode have been found in the mantle, the encysted cercarias 
 of Echinostomum secundum in the foot, and a third unidentified species encysted in the 
 liver. These trematodes, however, even when present in large numbers, work very 
 little injury to their host. 
 
 Several species of mollusks are commonly found living with the sea mussel. Oysters 
 are very often associated in the same beds with them and usually to the detriment of 
 the oyster, if the mussels are present in large numbers. The mussels, having the power 
 of free movement which the oysters do not possess, are able to acquire the more favorable 
 positions for collecting food and thus deprive the oysters of much nourishment. The 
 soft-shelled clam, Mya arenaria, and the hard-shelled clam, Venus mercenaria, are 
 sometimes found growing among the mussels in good, healthy condition. Boat shells, 
 Crepidida jornicata and C. convexa, are very common. Sometimes three or four individ- 
 uals are attached to a single mussel, covering it almost completely, but apparently doing 
 
FOOD VALUE OF SEA MUSSELS. 97 
 
 no injury. Large numbers of periwinkles, Littorina litorea, are usually present on the 
 beds, where, according to Allen and Todd (1902), by feeding upon the seaweed and 
 thus keeping down the growing vegetation, they are a positive benefit to the mussel. 
 
 DISTRIBUTION AND HABITAT. 
 
 The sea mussel has a very wide distribution, occupying most of the coast line of 
 the northern half of the Northern Hemisphere. It is circumpolar in range and extends 
 down our eastern coast to North Carolina, down the Pacific coast to San Francisco, 
 Cal., on the Asiatic coast to Japan, and on the European coast southward to the Medi- 
 terranean Sea. It is extremely abundant in the shallow, sheltered bays along the coasts 
 of New Jersey, Long Island, Rhode Island, and Massachusetts. 
 
 The mussel seems to grow equally well in shallow and deep water. The bathy- 
 metrical range is from the littoral zone to about 100 fathoms. In the channel between 
 Eastport, Me., and Deer Island, Verrill and Smith (1873) dredged them in from 40 to 
 50 fathoms and report that later their party dredged them in deeper water, but do not 
 state from what depth. Some of the beds near Boston, Lynn, and Vineyard Sound 
 lie in from 5 to 7 fathoms of water. 
 
 The favorite habitat of the mussel is where the water is slightly brackish, in shallow, 
 protected bays and estuaries, on a bottom of mud rich in diatoms and covered more or 
 less with stones or other solid objects to which it may attach by means of its byssal 
 threads. The swift tideways of shallow inlets are also very good situations for the 
 mussel. In these localities it is generally distributed from halfway between tide 
 marks to a level several feet below low water. Other situations chosen by the animal 
 are the piles and timbers of bridges, wharfs, and other objects, buoys, light-vessels, 
 and rocks. But these locations are not so advantageous as the first ones mentioned, 
 where mussels thrive in enormous beds, sometimes acres in extent, and where it is 
 possible for a man to collect them daily by the ton. 
 
 PRESENT USES OF SEA MUSSELS. 
 
 The sea mussel, which is practically unknown as a food in the United States outside 
 of New York City, has been utilized in other parts of the world for hundreds of years. 
 According to Quatrefages (1854) the artificial culture of mussels for food began as early 
 as the year 1035. Gould (1870) states that this shellfish is extensively used as a food in 
 England, France, Norway, and Russia, and that it is more palatable than the common 
 clam, Mya arenaria. Anderssen (1880) refers to it as a cheap and healthful food in 
 America, France, Spain, and Portugal, where it is eaten raw with vinegar and pepper or 
 boiled with milk. Goode (1884) writes that in Europe Mytilus holds an important place 
 among the sea foods. Ganong (1889) says that as a food in Europe the mussel ranks 
 second only to the oyster and takes the place of the soft-shelled clam, which is not 
 eaten. This state of affairs we find at present reversed in America, where the soft- 
 shelled clam is so popular that there is danger of the demand exceeding the supply, 
 while the mussel, although exceedingly abundant, remains almost unutilized. 
 
98 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 In the early colonial days, however, the settlers did eat mussels, as may be seen in 
 Lescarbot's description of De Mont's settlement at St. Croix Island (Dochet Island of 
 to-day), written in 1604. From this account Ganong (1889) makes the following 
 quotation : 
 
 There is a little chapel built after the fashion of the savages, at the foot of which there is such a 
 store of mussels as is wonderful, which may be gathered at low tide, but they are small. I believe 
 that Monsieur De Mont's people did not forget to choose and take the biggest and left there but the 
 small ones to grow and increase. 
 
 Of how the change in attitude toward the mussel and clam came about Ganong 
 (1889) offers a very plausible explanation. He attributes it to the influence of the 
 Indians, who ate the soft-shelled clam to the almost total neglect of the mussel, which, 
 without reason, they superstitiously avoided. He furthermore thinks that this was 
 unfortunate for us, since the mussel is a superior article of food. Goode (1887) refers 
 to the use of mussels on the northwest coast of America, where it is the chief moUuscan 
 food. The Indian women and children collect them from the rocks every day the year 
 around. Mussels are also consumed by the white inhabitants of that region. The 
 Russian name for them is "black shells" (chornie rakooshka). In Alaska the method 
 of cooking is by boiling; on Vancouver Island they are more commonly roasted. 
 
 Aside from being useful as an article of food, the sea mussel is valuable for other 
 purposes, the most important of which is bait. In England the mUssel is valued as 
 the best hook bait known. The quantity used in Great Britain for this purpose amounts 
 to more than 100,000 tons annually. In this country, however, fishermen rank it 
 second to the squid in bait value. 
 
 Next in importance the mussels are valuable for the production of fertilizer. The 
 so-called mussel mud constitutes one of the best fertilizers known. It is formed in 
 places where the mussel beds are exposed to constantly depositing silt, which slowly 
 destroys the mollusks and buries them beneath their offspring. The slow accumulation 
 and decay forms a mass of very rich fertilizer, enormous quantities of which are taken 
 along the coasts of Long Island and New Jersey, where it is considered excellent for 
 carrots and onions. Goode (1887) stated that for the last thirty years he had seen it 
 applied to lands where onions had been grown with a product varying from 300 to 600 
 bushels per acre. At that time the mussel mud sold, delivered several miles from where 
 it was dug, at $4 to $5 a cord. It is gathered during the winter, piled up and exposed 
 to the frosts, and then distributed in amounts of from 4 to 8 cords to the acre. For 
 bait and fertilizer the value of the mussel fishery to the United States is estimated at 
 $37,500 annually. 
 
 Pearls of some value are sometimes found in mussels. Usually, however, although 
 quite commonly present, they are small and of such poor color that the price they bring 
 is low. In England they have been sold for from is. 6d. to 4s. per ounce. 
 
 The shells can be used by oyster planters for cultch upon which to catch oyster 
 spat. When polished, they may be used in numerous ways. Artists use them as 
 receptacles for gold or silver paint. They may be mounted on marble for paper weights 
 
FOOD VALUE OF SEA MUSSELS. 99 
 
 or made into pretty needle books and scent bottleholders, earrings, crosses, pins, and 
 pin cushions. It is said that the American Indians and the natives of New Zealand 
 used the mussel shells as tweezers for pulling out their beards. 
 
 SEA MUSSELS AS FOOD. 
 
 The fact that the sea mussel is so widely used as a food and yet is not utilized to 
 any extent in the United States, where it grows prolifically in great beds, has led me to 
 investigate its properties as a human food and to determine whether or not there is any 
 reason for not making wide use of it in our diet. A food substance to be of value must 
 measure up well to four standards. It must be palatable, digestible, nutritious, and 
 economical. 
 
 By palatable I mean that the substance must have a flavor that will appeal to the 
 average man's taste. To determine this quality, I found it necessary first to taste or 
 eat the substance in question myself. If the flavor was agreeable and no evil results 
 followed its use, I persuaded members of the Woods Hole scientific staff to follow my 
 example and express their opinions concerning the dish. If they gave a favorable 
 report, I had mussels served on certain tables of the Marine Biological Laboratory 
 mess hall and to other persons who were interested enough to try them. The general 
 opinion expressed was taken as an indication of the palatability of the food. By this 
 method it was often possible, also, to obtain criticisms which would suggest new ways 
 of preparing the substance to improve its flavor. 
 
 The second standard, digestibility, means several things. It relates to the propor- 
 tion of the food that can be digested, to the ease or rapidity with which it can be digested, 
 and to the degree in which the material agrees or disagrees with the user. Compara- 
 tively little is known concerning the relative rapidity of digestion of different foods 
 within the body. Most of the current statements referring to this are apparently based 
 on experiments carried on outside of the body, and it is certain that the processes in the 
 two cases are not exactly the same. The artificial process takes much longer than the 
 natural one, although the relative rates of digestion as regards different substances 
 appear to be much the same. For example, under natural conditions, soft boiled eggs 
 will digest more quickly than hard boiled ones. The same proportionate results are 
 obtained by the artificial method. The artificial process serves merely to determine 
 the rate of digestion of the substance compared with that of staple foods. How it 
 agrees or disagrees with the user can only be determined by taking the article into one's 
 own stomach and awaiting results. 
 
 The third standard, nutritive value, involves such questions as the ratio of edible 
 portion to refuse and the chemical composition and proportion of nutriment that can 
 be absorbed by the body under normal conditions. 
 
 The fourth standard, economy, means that a food of high nutritive value must be 
 so abundant and easily obtained that it can be sold reasonably cheap. If it can be 
 readily prepared in various ways so that it may be preserved for long periods, its value 
 is still further increased. Any food that measures up well to these four standards ought 
 to find a large and ready market. 
 59730°— II 3 
 
lOO BULLETIN OF THE BUREAU OF FISHERIES. 
 
 PALATABILITY. 
 
 From the standpoint of palatability I have abundant testimony from scores of 
 persons who have eaten mussels prepared in various ways (pickled, steamed, roasted, 
 stewed, and fried) that in flavor and texture they are superior to the long clam and 
 fully equal to the oyster. A few people were incHned to rank them not so high. On 
 July 30, 1907, pickled mussels were served on three tables of the Marine Biological 
 Laboratory mess hall. About 36 persons ate of them and all expressed their appre- 
 ciation of the unfamiliar dish. The only adverse criticism that was made related to the 
 tough, muscular part of the foot, which was difficult to masticate. 
 
 Two days later one of the residents of Woods Hole was given four dozen mussels, 
 which he took home for family use. He had them steamed and ser^^ed with salt, pepper, 
 butter, and oil. They were pronounced "elegant and superior to clams." 
 
 On August 3, 1907, mussels dipped in egg and cracker crumbs were fried and served 
 to about 25 persons at the Marine Biological Laboratory mess hall. They were declared 
 to be equal to or better than fried oysters, and were so reHshed, in fact, that there was a 
 general call for more. A few days later, in answer to this request, a large quantity 
 was prepared and served to 40 persons. Enthusiastic comments were made as to the 
 appetizing appearance, rich flavor, and delicate texture of the flesh. 
 
 nOu August 13 mussel chowder was served to the same 40 persons and called forth 
 the same favorable comments, especially as to richness of flavor and tenderness of the 
 meat. The tender quality of the flesh is a point decidedly in favor of the mussel when 
 compared with the clam, the meat of which latter in chowder is so tough that few persons 
 ever think of trying to masticate it. 
 
 Mussel fritters were next tried on the tables of the mess hall on August 27. They 
 were eaten with relish and pronounced excellent. 
 
 The following year, 1908, the work of preparing mussels in various ways and serving 
 them in the mess hall to friends and visitors of the Bureau's laboratory was continued, 
 with the result that quite a general interest in the food value of this shellfish has been 
 aroused and a local demand now exists. For some years past at certain points along 
 the coast of Rhode Island, New York, and New Jersey a few people have been in the 
 habit of collecting mussels for their own personal use. Some of the summer visitors 
 also have learned to eat them. I have met several persons living in the vicinity of 
 New York City who say they have always prized the sea mussel as a food and that it 
 is their custom to pickle a number every summer for use during the winter. 
 
 For the benefit of those interested in making use of the mussel in their diet, a few 
 recipes for cooking them will be given in another section of this paper. They have been 
 tried repeatedly and have proved to make most palatable dishes. 
 
 DIGESTIBILITY. 
 
 Personal testimony in various instances is very favorable to mussels for their 
 digestibility. Persons with weak stomachs say that the)/ can eat them without suffering 
 any inconvenience. Others have eaten them just before retiring and experienced no 
 
FOOD VAIvUE OF SEA MUSSEI.S. lOI 
 
 discomfort. One man with whom meat does not ordinarily agree states that he can 
 eat freely of mussels and digest them without difficulty. Many persons have declared 
 that in their opinion mussels are more digestible than either clams or oysters, a fact 
 due to the character and properties of the flesh which by cooking is rendered tender 
 and mealy, whereas the oyster and clam become very tough. 
 
 But the problem of really determining the digestibility of a given food material is 
 surrounded with great difficulties. It is an easy matter for one to eat the food and learn 
 by experience how it agrees or disagrees with him; but to determine the rate of diges- 
 tion and the proportion of nutriment which the body absorbs from a given quantity of 
 the food involves a series of very complex chemical studies. 
 
 EXPERIMENTS TO SHOW AVAII.ABLE PROTEIN. 
 
 By artificial methods it is possible, however, to determine approximately the pro- 
 portion of protein which is rendered soluble and absorbed by the animal body. Diges- 
 tion experiments of this sort were made by Dr. C. L. Alsberg. His method and results 
 are as follows : 
 
 ^ Mussels, hard-boiled eggs (yolk and white together), and thoroughly boiled beef were each ground 
 up in an ordinary kitchen sausage machine. Each chopped-up sample was thoroughly mixed to make 
 it as uniform as possible. Then 5-gram samples were weighed out. Each sample was placed in a 
 fiask containing 100 c. c. of artificial gastric juice. This juice was prepared by dissolving 0.5 gram 
 pepsin in i liter 0.15 per cent hydrochloric acid. All the flasks were placed in a thermostat at a 
 temperature of 38° C. At stated intervals they were all shaken by hand. After two hours one-half 
 the flasks were removed from the thermostat. The remainder were removed after four hours. Imme- 
 diately after taking them out of the thermostat each flask was brought to a boil in order to destroy 
 the enzymes. Each was then filtered through an ash-free quantitative filter, and when all the Hquid 
 had passed through the filter the undissolved residue was washed with 100 c. c. of distilled water. 
 When all the wash water had passed through the filter, the amount of nitrogen was determined by 
 the Kjeldahl method in the combined filtrate and wash water as well as in the undissolved residue. 
 From the relative amounts of nitrogen in the filtrate and undissolved residue an opinion may be 
 formed as to how much protein has been rendered soluble by the action of the gastric juice. This 
 method is not accurate, but it is believed to be more accurate than the methods commonly employed, 
 in which the various digestion products are precipitated out and weighed. The washing and drying 
 of such proteins upon filters presents great difficulties. It is believed that the determination of the 
 nitrogen rendered soluble gives a better index of the effect of the digestion. The figures obtained 
 were multiplied by 6.25 to indicate the amount of protein corresponding to them. The resulting 
 figures are given in the following table, each figure representing the average of several experiments: 
 
 Table I. — Results of Experiments to show Available Protein in Mussels. 
 
 Substance. 
 
 Protein in 
 filtrate. 
 
 Protein in 
 residue. 
 
 Per cent dis- 
 solved. 
 
 For two hours' digestion: 
 
 Mussels 
 
 Grams. 
 
 1. 1656 
 
 . 6107 
 • 7455 
 1.2930 
 
 Gram. 
 0. 2012 
 . 1866 
 
 • 2705 
 
 . 1522 
 . 2104 
 .1450 
 
 
 Egg : 
 
 76.0 
 81. I 
 
 80,0 
 
 Beef ;...: 
 
 For four hours' digestion: 
 
 Mussels 
 
 Egg 
 
 Beef ;.;;: 
 
 77-9 
 96.7 
 
 
I02 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 It will be seen that under the conditions of these experiments there was no very 
 great difference in the digestibility of the egg and the mussels, while the beef was con- 
 siderably more digestible than either. It must, however, be pointed out that beef has 
 more nitrogenous extractives than egg and that the greater digestibility of the beef 
 may be accounted for in part by the fact that under the conditions of these experiments 
 the nitrogenous extractives are calculated as protein. How much nonprotein nitroge- 
 nous extractives mussels contain is not known. It must be noted, however, that, judged 
 by sight, the greater part of the mussels went into solution. The undissolved portions 
 consisted mainly of the tough portions, such as the foot and posterior adductor muscle. 
 
 Finally, it should be pointed out that experiments such as these must be inter- 
 preted cautiously. Digestion in vitro is surely not so effective as digestion in the intes- 
 tinal canal. It is even probable that in the intestinal canal all these three foodstuffs 
 may be equally perfectly utilized. This can be determined by careful metabolism 
 experiments. 
 
 METABOLISM EXPERIMENTS. 
 
 The metabolism experiments were made a special subject of research by Dr. Donald 
 D. Van Slyke, assisted by Messrs. W. M. Clark and C. B. Bennett. In Doctor Van 
 Slyke's report, which follows, the rate of digestion and proportion of nutriment absorbed 
 from cooked mussels and squid is compared with that of beef as a standard : 
 
 The work outlined was undertaken to determine the comparative rapidity and completeness with 
 which various sea foods are digested, absorbed, and utilized in the animal organism and the effects of 
 different modes of preparation and preservation upon the food value. The substances were compared 
 with beef as a standard. The experimental animal was a fox terrier bitch of 1 2 J 2 pounds weight. While 
 more valuable results, from a practical standpoint, might be obtained from experiments on men, the 
 latter could not tolerate for a long time the simple diet used, nor be subject to regular catheterization. 
 The experiments, furthermore, were for comparison of the behavior of different protein foods under the 
 same conditions, and it is probable that the foods would rank in the same order when tested in dogs or 
 in men, although the absolute completeness and rapidity of utilization varies with different species 
 and individuals. 
 
 PRINCIPLES OF METHODS. 
 
 The daily rations were so proportioned, from analyzed foods, that the dog obtained just the amount 
 of protein required to maintain nitrogenous equilibrium. Fats and carbohydrates were also kept 
 constant. The amount of protein digested was calculated from analysis of the food and feces, the 
 nitrogen in the latter being ascribed to undigested protein. The rate at which the protein is digested, 
 absorbed, and utilized is measured by the rate at which its nitrogen is excreted in the urine. 
 
 METHODS IN DETAIL. 
 
 The dog was brought to nitrogenous equilibrium by feeding on a constant diet of cracker dust, 
 lard, lean beef, and salt. In the experiments with fish flesh, the beef was replaced by an amount of 
 steamed fish meat. The fish was cleaned and the flesh steamed immediately after the fish was caught, 
 in order to prevent autolytic or bacterical changes. The remainder of the ration was the same as 
 in the beef diet, except the amount of lard was reduced in proportion to the fat content of the fish flesh, 
 so that the fat content of the ration was kept the same as in the standard beef diet. All foods were 
 analyzed for nitrogen and fat. On alternate days animal charcoal was mixed with the ration, in order 
 that the feces from food consumed on successive days might be separated by their colors. In case 
 the entire daily ration was not consumed, the remainder was fed through a tube. 
 
FOOD VAIvUE OF SEA MUSSELS. 
 
 103 
 
 The animal was catheterized immediately before feeding the day's ration, and at three-hour intervals 
 thereafter for twelve hours, then again at the end of twenty-four hours after feeding, the bladder being 
 washed out with 0.6 per cent sodium chloride solution at each catheterization. The nitrogen excreted 
 in the urine during each interval was determined by Kjeldahl analysis. The urine obtained at each 
 catheterization, combined with the cage washings in case the dog had urinated during the interval, 
 was acidified with sulphuric acid, diluted to 500 or 1,000 volumes, and one-twentieth taken for 
 analysis. 
 
 The feces containing the undigested portions of each day's rations were collected and the nitrogen 
 content determined. The animal charcoal in the alternate day's feces made a separation possible, 
 and the 5 grams of bone ash fed daily insured a well-formed, solid stool. 
 
 It was found that analysis of both food and feces for nitrogen and fat could be made accurately 
 without preliminary drying in a dessicator. For fat analysis about 10 grams of the fresh material were 
 ground up with anhydrous copper sulphate until the mixture became a dry, homogeneous powder. 
 This was extracted for about ten hours with carbon tetrachloride, ground again, and reextracted for 
 a few hours. Representative samples of flesh for nitrogen determination were obtained by grinding 
 the flesh as fine as possible in a meat grinder, and taking 2 grams or more for the sample. 
 
 The daily diet consisted of 25 grams of fat, 50 grams of cracker dust, and sufficient beef or fish flesh 
 to bring the total nitrogen of the diet up to the amounts indicated in the table. About three-fourths 
 of the protein ration was contained in the flesh, the other one-fourth in the cracker dust. To the lard, 
 cracker dust, and meat were added 5 grams of sodium chloride and 5 grams of bone ash. 
 
 After being fed squid for two days, the dog refused to consume completely the rations ofTered and 
 was partially starved for several days. During the feeding of raw beef and squid she consumed and 
 excreted 2.5 grams of nitrogen daily, as indicated in the two lower curves of the figure. 
 
 The results are briefly indicated by the following tables and figure : 
 
 Table 2. — Showing Results of Metabolism Experiments. 
 
 
 
 Ration containing — 
 
 
 
 Raw beef. 
 
 Steamed 
 squid. 
 
 Steamed 
 beef. 
 
 Steamed 
 mussel. 
 
 
 2-497 
 .423 
 2. 074 
 83.1 
 
 2. 505 
 .291 
 
 2.08s 
 .285 
 1.800 
 86.3 
 
 
 
 . 444 
 
 
 1.687 
 
 
 
 
 
 
 Ration containing — 
 
 
 Raw beef. 
 
 steamed 
 squid. 
 
 Steamed 
 beef. 
 
 Steamed 
 mussel. 
 
 
 + 0. 0.x 
 
 2.505 
 
 2.485 
 
 + 0.02 
 
 .OS, 
 
 I. 910 
 
 + 0. 18 
 
 2. 131 
 
 Nitrogen in urine +feces 
 
 2. 117 
 + 0.01 
 
 
 
 CONCLUSION. 
 
 The above results indicate (table 2) that the protein of the ration containing steamed mussel 
 was digested somewhat less completely (79.1 per cent) than that of raw beef (83.1 per cent), while the 
 squid gave higher results (88.4 per cent) than the raw beef. The steamed-beef figures (in table, not 
 in the figure) are of doubtful accuracy, as a portion of the feces may have been lost, causing the high 
 figures for digestibility (exceeding those of raw beef, which is improbable) and for nitrogen retention 
 The digestibility figures indicate only the relative digestibility of the meats fed. A considerable 
 
I04 
 
 BULIvETiN OF THE BUREAU OF FISHERIES. 
 
 proportion of the undigested (fecal) nitrogen is due to the cracker-dust protein, which is known to be 
 less digestible than ordinary flesh proteins. Consequently, in order to determine the digestibility of 
 the meat proteins alone, a correction must be applied for the undigested vegetable protein. Unfor- 
 tunately, we lacked time to determine this correction. 
 
 The urine curves must be considered in pairs, because the amount of nitrogen given in the raw-beef 
 and steamed-squid diets was greater than that given later in the steamed-beef and mussels ration. 
 The beef and squid (upper) curves show that the beef protein was metabolized more rapidly, as the beef 
 curve rises more rapidly after feeding. The difference is not great, however, and the total amount 
 of squid nitrogen metabolized and excreted in the urine in twenty-four hours is slightly the greater, 
 coinciding with the fact that less squid nitrogen was found in the feces. Apparently squid proteins 
 are digested slightly less rapidly than those of beef, but more completely 
 
 The steamed-beef and Mytilus curves show a similar relation, the beef being metabolized more rap- 
 
 z.oo 
 
 /.so 
 
 ■ t.oo 
 
 . o.so 
 
 . — Curves showing results of metabolism experiments. Figures on base line indicate number of hours 
 since feeding. Figures in vertical line at right show number of grams of nitrogen excreted in urine. 
 
 idly in the hours immediately following feeding, the Mytilus curve overtaking and passing the beef 
 curve later, however. 
 
 The raw-beef figures are taken from three successive days' results, the figures for the other meats 
 from the results of two days' experiments each. The brief time (less than three weeks) available pre- 
 cluded longer tests, which would have been desirable, and limited the experiments to those above 
 reported. They must be regarded as merely preliminaries to a thorough investigation of the problem. 
 
 It is clear, from the evidence just presented, that the mussel measures up well to 
 the standard of digestibility. It agrees well with the consumer and the rate of digestion 
 and proportion of nutrients supplied to the body approximate very nearly those of 
 steamed beef. 
 
FOOD VAI,UE OF SEA MUSSELS. 
 COMPOSITION AND NUTRITIVE VALUE. 
 
 105 
 
 The function of food is to build up new tissues and repair them as they are worn 
 out by use, to supply heat energy for keeping the body warm and muscular energy for 
 doing work. The nutritive value or degree to which a food material is able to perform 
 this function depends upon two factors, (i) the ratio of edible portion to refuse and (2) 
 the relative amounts of nutrients contained in the edible portion. The first of these is 
 determined by separating the flesh and liquor from the shells and byssus of the mussels, 
 then weighing them separately and determining the percentage of each present. The 
 second factor is determined by means of a chemical analysis of the edible portion. 
 
 The nutrients sought represent four classes of compounds: (i) Protein, which forms 
 the nitrogenous basis of blood, muscle, connective tissue, etc.; (2) carbohydrates; (3) 
 fats, which may be stored up as fat or consumed for fuel; and (4) mineral matters or 
 ash, which are used chiefly in the formation of bone. 
 
 In studying the ratio of edible portion to refuse two sets of determinations were 
 made. One was based on the examination of fresh or uncooked specimens and the 
 other on mussels which had been cooked by steam. In the first case the mussels were 
 weighed after being washed free from dirt. They were then quickly shucked and 
 "bearded," the meats and Uquor being preserved in separate dishes. What liquor 
 adhered to the flesh was drained off and added to the other dish. The weights of the 
 flesh and liquor were ascertained and recorded. The total weight of the mussels minus 
 the combined weights of the flesh and liquor was considered the amount of refuse 
 matter. This method, it will be obser/ed, places the loss due to handhng in the refuse 
 column. The results obtained from the examination of five separate lots of mussels will 
 be found in the following table : 
 
 Table 3. — Showing Proportion of Edible Parts to Refuse in the Sea Mussel. 
 Determinations from fresh or uncooked material. 
 
 Date. 
 
 Num- 
 ber 
 taken. 
 
 Total 
 weight. 
 
 Aver- 
 weight. 
 
 Flesh. 
 
 Liquids. 
 
 Total 
 edible 
 portion. 
 
 Refuse. 
 
 Flesh. 
 
 Liquids. 
 
 To*al 
 edible 
 portion. 
 
 Refuse. 
 
 1908. 
 
 5° 
 100 
 50 
 20 
 
 Lbs. oz. 
 5 4 
 9 13 
 4 S 
 2 3 
 
 Ounces. 
 1.68 
 I-S7 
 1-39 
 1.76 
 1.68 
 
 Lbs. oz. 
 
 If 
 
 Lbs. oz. 
 I 6^ 
 
 I \ 
 10 
 45 
 
 Lbs. oz. 
 2 i4i 
 
 9l 
 
 Lbs. oz. 
 
 : ?! 
 
 7l 
 
 Per cl. 
 
 28.87 
 28.75 
 25-35 
 26. 10 
 30.80 
 
 Per ci. 
 26. 78 
 25.48 
 23- 74 
 29. 00 
 25.00 
 
 Per ct. 
 
 55.65 
 54- 23 
 49-09 
 
 Mil 
 
 Perct. 
 44.35 
 45-77 
 50.91 
 44.90 
 44-20 
 
 
 
 
 August 28 
 
 
 Total 
 
 231 
 
 22 III 
 
 I-S7 
 
 6 S 
 
 5 i3i 
 
 12 2% 
 
 10 81 
 
 27.79 
 
 25.75 
 
 53.54 
 
 46.46 
 
 In the second case the total weight, as above, was taken after washing the mussels 
 free from dirt, but before removing the meats and liquor the shellfish were cooked by 
 means of steam until the shells began to open. This treatment gives very different 
 results from those obtained from the raw material, as may be seen in the following: 
 
io6 
 
 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 Table 4. — Showing Proportion of Edible Parts to Refuse in the Sea Mussel. 
 Determinations from steamed material. 
 
 1907 
 August 12.. 
 
 Do.. . . 
 August 13. . 
 
 Do ... . 
 August 14.. 
 August IS. . 
 August 26. . 
 August 27.. 
 August 28. . 
 1908 
 
 July 9 
 
 July 12 
 
 July 15 
 
 July 16 
 
 July 30 
 
 August 8. . . . 
 August 10. . . 
 August II.., 
 August 14. . . 
 
 Total. 
 
 Num- 
 ber 
 taken. 
 
 Total 
 weight. 
 
 Aver- 
 age 
 weight. 
 
 Ounces. 
 1.34 
 1.44 
 1.38 
 1-33 
 1-33 
 1-35 
 1.42 
 I. 21 
 1.63 
 
 1.60 
 1.70 
 
 3 3 
 3 8 
 3 13 
 
 Total 
 edible 
 portion. 
 
 Lbs. 
 3 I 
 
 .S6 
 
 15- 
 
 ..S8 
 
 7- 
 
 ■ ss 
 
 10. 
 
 .92 
 
 1 1 . 
 
 .■^8 
 
 12. 
 
 .18 
 
 13- 
 
 ■ 14 
 
 10. 
 
 ■2.S 
 
 10. 
 
 • 71 
 
 5- 
 
 . 00 
 
 6. 
 
 ■52 
 
 8. 
 
 ■ 79 
 
 7- 
 
 .34 
 
 7- 
 
 . 26 
 
 8. 
 
 • 70 
 
 5- 
 
 ■55 
 
 4- 
 
 .84 
 
 4- 
 
 • 15 
 
 12. 
 
 Total 
 edible 
 portion. 
 
 Per ct. 
 63- 44 
 72.92 
 69. II 
 68.37 
 
 66. 92 
 65.63 
 69.89 
 
 67. 25 
 76.74 
 
 72. 40 
 72- 03 
 74- 41 
 79-31 
 80.81 
 83. 00 
 66.56 
 
 A comparison of the two tables reveals a wide difference in the ratios of edible 
 parts to waste. In case of the raw material it is 53.54 per cent of meat and liquor to 
 46.46 per cent of refuse. With the cooked material it is 28.13 P^r cent to 71.87 per cent. 
 This great dissimilarity of results is due to two facts. In the first place, cooking 
 removes considerable water from the flesh and in the second place the opening of 
 the shells of many of the mussels during the process of cooking causes considerable 
 loss of the natural liquor. The loss of water and liquor is thus added to the refuse 
 column and makes the difference between the useful and waste parts appear greater 
 than it really is. These figures apparently indicate that much loss of food material 
 results from cooking, but such is not the case. The loss in weight is due almost entirely 
 to the extraction of water. 
 
 A comparison of the mussel with the oyster and long clam on the basis of the rela- 
 tive amounts of edible parts to refuse will help one to appreciate its real value as a food. 
 The figures used for this purpose are taken from Atwater (1891) and incorporated in 
 the following table: 
 
 Table 5. — Showing Percentage of Edible Parts and Refuse in the Mussel, Long Clam, and 
 
 Oyster. 
 
 Kinds of shellfish. 
 
 Number 
 of speci- 
 mens. 
 
 Edible portion. 
 
 Refuse 
 (shells, 
 etc.). 
 
 Flesh. 
 
 Liquids. 
 
 Total. 
 
 
 so 
 
 441 
 
 3.383 
 
 Per cent. 
 32.66 
 34.77 
 9.81 
 
 Per cent. 
 
 18.00 
 21. 78 
 7.6s 
 
 Per cent. 
 50.66 
 
 Per cent. 
 46.69 
 41.77 
 
 
 
 
 
 Measured by the above standard, the mussel contains about the same proportion 
 of flesh and liquids as the long clam and about three times as much as the oyster. If 
 
FOOD VAI,UE OF SEA MUSSELS. I07 
 
 the flesh of each species contained the same amount of nutrients we might conclude that 
 for equal weights of the shellfish the food value of the mussel is about equal to that of 
 the long clam but three times that of the oyster. This obvious superiority over the 
 oyster is due to the thin, light shell of the mussel, which stands in sharp contrast to 
 the heavy, thick shell of the oyster. A consideration of the chemical composition of 
 these forms, however, will show that the difference in food value between the mussel 
 and oyster is even greater than is indicated by the above table. 
 
 The account which follows is taken from Doctor Alsberg's personal report to me. In 
 view of the fact that the methods used in making the analyses differ in some important 
 particulars from those employed by Atwater (1891), with whose results comparisons 
 are made, it is necessary to describe them briefly. 
 
 In preparation of a sample a large quantity of the mussel meats was ground up in a 
 meat chopper and the ground-up sample thoroughly mixed. Of this, a small sample 
 of 50 grams was weighed out into a weighed glass dish. Enough sulphuric acid was 
 added to make the reaction neutral. As the reaction of the juices of invertebrates 
 is very alkaline, this is a most important matter. If it is neglected, much nitrogen is 
 lost as ammonia. This precaution has apparently not been taken by Atwater or any- 
 one else. Probably Atwater's figures for oysters are too low for this reason. Doctor 
 Alsberg's high nitrogen values are probably in part due to this method. The glass dish 
 containing the 50 grams of neutral material was then evaporated to dryness on the 
 steam bath, with care that the reaction remained neutral. Atwater dried in a stream 
 of hydrogen. There were no facilities for doing this in the present work, but it is thought 
 that the results are unaffected, except to a slight extent for the fat determinations. 
 
 The material thus dried was very difficult to pulverize, partly because of the fat 
 content, which made it greasy, and partly because invertebrates contain hygroscopic 
 salts. Therefore the material was boiled out with 95 per cent alcohol until the latter 
 was colorless. The alcoholic solution was made up to a known volume and analyzed 
 by itself. The results were added to those obtained from the residue. The sum of the 
 two gives- the figures for the total. The residue from the alcohol was easily ground up 
 and sampled in an agate mortar. The material for all the determinations was weighed 
 out at the same time. In addition, about 1.50 grams were weighed in a weighing bottle 
 and dried at 60° C. in vacuo over sulphuric acid in a Schmiedeberg drying apparatus. In 
 this way the total quantity of water was determined and the determinations calculated 
 accordingly. The water determinations are therefore more correct than those of Atwater. 
 
 The fat determinations were done by extracting with carbon tetrachloride (CCI4) 
 in a Soxhlet apparatus. It was not safe to use ether, as Atwater did, because of the 
 danger of fire in a wooden building. As carbon tetrachloride is a better solvent than 
 ether, the figures obtained are naturally a little higher than those of Atwater. Another 
 reason why they are higher is that the material was not dried in hydrogen. 
 
 Nitrogen was determined by the Kjeldahl method, which had not been discovered 
 in Atwater's time. He used the soda-lime method, which is probably as good. 
 
 Atwater made no determinations of carbohydrates. Inasmuch as the oyster con- 
 tains much glycogen, an attempt was made to determine glycogen in the mussel. This 
 
io8 
 
 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 was done by Pfluger's method in its latest modification: One hundred grams of abso- 
 lutely fresh material were used and the determination begun at once to prevent the 
 hydrolysis by enzymes. The purified glycogen was determined in three ways: (i) It 
 was filtered through a weighed Gooch crucible, dried, and weighed. It was then ashed 
 and the crucible weighed again. The weight of the ash, which was always under 2 
 per cent, was then subtracted, and the resulting figures are those given in the table. 
 (2) The glycogen was then hydrolyzed with dilute sulphuric acid and the sugar deter- 
 mined titrametrically with Fehling's solution. (3) The glycogen was hydrolyzed with 
 dilute sulphuric acid and the resulting sugar determined in the polariscope. 
 
 The figures for flesh calculated on fresh substance do not quite total 100 per cent. 
 This is probably not due to errors in methods or technique, but to errors of calculation. 
 Thus the proteins are calculated arbitrarily. It is assumed that all nitrogen is present 
 as protein, whereas as a matter of fact some is in the form of extractives and some in the 
 form of fats (lipoids). It is assumed, further, that the proteins of mussels have the 
 same nitrogen content as those of vertebrates. As they have not been investigated, 
 this is an arbitrary assumption, and the factor 6.25 may be wrong. Moreover, as some 
 of the nitrogen is in the fat (lipoids) , this figures twice in the tables, once as protein and 
 once as fat. The crude ash, too, does not quite correctly represent the inorganic sub- 
 stances of the mussel, because in the process of ashing some is volatilized, while new 
 phosphoric acid and sulphuric acid are formed from the protein. All these, however, 
 are errors inherent in all analyses of this nature. 
 
 The structure of the flesh of male and female mussels being very different (compare 
 figs. 2 and 3, pi. xxiii), separate analyses were made of the two sexes. The distinction of 
 the sexes was based on the color of the mantle, white flesh being called male and red flesh 
 female. This method of separation is, however, not absolutely accurate. Microscopic 
 examination revealed the fact that in about 2 per cent of the cases a red mussel might 
 be a male and a white or cream-colored one a female. The results of the analyses are as 
 follows : 
 
 Table 6. — Showing Composition ok Mussels Calculated for Water-Free Substance. 
 
 [August IS, 1908.] 
 
 White flesh 
 (male). 
 
 Red flesh 
 (female). 
 
 Average for 
 white and 
 red flesh. 
 
 In flesh: 
 
 Nitrogen 
 
 Protein (NX6.25). 
 
 Fat. CCh Ext 
 
 Carbohydrate .... 
 
 Crude ash 
 
 In liquids: 
 
 Nitrogen 
 
 Protein (NX6.25) . 
 
 Fat. ecu Ext 
 
 Carbohydrate .... 
 
 Crude ash 
 
 In total edible portion: 
 
 Nitrogen 
 
 Protein (NX6.25) . 
 
 Fat, ecu Ext 
 
 Carbohydrate . . . . 
 
 Crude ash 
 
 Per cent. 
 
 9.3s 
 58.44 
 
 8.51 
 13.61 
 
 6. 74 
 
 Per cent. 
 
 10. OS 
 63-31 
 10. 26 
 II. SI 
 6.38 
 
 362 
 
 22. 62 
 
 .28 
 
 Trace. 
 
 6550 
 
 9. 19 
 57-43 
 8.93 
 9-97 
 14-27 
 
FOOD VAI,UE OF SEA MUSSELS. 109 
 
 Table 7. — Showing Composition of Mussels Calculated for Fresh Supstance. 
 
 [August IS, 1908.] 
 
 Ingredients. 
 
 White flesh 
 (male). 
 
 Red flesh 
 (female). 
 
 Average for 
 white and 
 red flesh. 
 
 In flesh: 
 
 Water 
 
 Per cent. 
 76.62 
 2.44 
 
 3- 19 
 1.S8 
 
 Per cent. 
 
 76.18 
 2.46 
 
 15.38 
 3- 10 
 2. 24 
 I. 44 
 
 Per cent. 
 
 76. 40 
 2.45 
 
 15-31 
 2-54 
 2.71 
 I-5I 
 
 95.64 
 
 
 Protein (NX6.2s) . . . 
 
 Fat ecu Ext 
 
 
 Crude ash 
 
 In liquids: 
 
 Water 
 
 Nitrogen 
 
 
 
 Protein (NX6. 25) 
 
 
 
 • 99 
 
 Fat, CCh Ext 
 
 
 
 Carbohydrate 
 
 
 
 
 Crude ash 
 
 
 
 2 86 
 
 In total edible portion: 
 
 Water 
 
 
 
 '\-ll 
 
 Nitrogen 
 
 
 
 Protein (NX6 25) . ... 
 
 
 
 
 Fat. ecu Ext 
 
 
 
 
 Carbohydrate 
 
 
 
 
 Crude ash. . . 
 
 
 
 1.99 
 
 
 
 
 The above figures indicate that, for a shellfish, the mussel contains a high percentage 
 of each of the four classes of food materials and that the white-fleshed individuals (males) 
 differ considerably in chemical composition from the red-fleshed ones (females), the 
 latter containing a much higher percentage of protein and fat but less carbohydrate. 
 This difference is accounted for by the fact that the whole body of the female, during 
 the spring and summer, is distended with eggs which are rich in yolk material. It is 
 during this season, therefore, that the mussels are at their best as a food. 
 
 A fair idea of the food value of the mussel may be obtained by comparing its fuel 
 value with those of several standard food materials, e. g., oysters, long clams, and 
 beef. Fuel value refers to the number of calories of heat equivalent to the energy 
 which the body is supposed to obtain from i pound of a thoroughly digested food 
 material. The fuel values of various food materials are calculated by using the factors 
 of Rubner, which, in terms of the English system of weights, correspond to i,86o calories 
 of energy for every pound of protein or carbohydrate and 4,220 calories for each pound 
 of fat. 
 
 Table 8. — Showing Comparative Fuel Values of Mussels, Oysters, Long Clams, and Lean 
 
 Beef. 
 
 Food materials. 
 
 Refuse. 
 
 Water. 
 
 Protein 
 
 (NX6.2S). 
 
 Fat. 
 
 Carbohy- 
 drate. 
 
 Ash. 
 
 Fuel value 
 per pound. 
 
 
 Per cent. 
 46.69 
 
 Per cent. 
 41. I 
 83.3 
 16. I 
 86.9 
 49-9 
 85.8 
 55-3 
 
 Per cent. 
 
 Per cent. 
 
 8 
 
 Per cent. 
 8s 
 
 Per cent. 
 
 Calories. 
 
 
 10 
 
 6 
 
 5 
 8 
 
 18 
 
 2 
 
 
 6 
 
 7 
 
 
 64 
 2 
 2 
 6 
 
 
 
 I 
 3 
 
 74 
 
 7 
 7 
 
 
 
 1.99 
 
 . 4 
 2.0 
 
 IS 
 
 2.6 
 
 .8 
 
 290 
 
 
 81.4 
 
 
 
 
 
 41.9 
 
 140 
 
 
 240 
 
 Beef, hind quarter as purchased «... 
 
 16.6 
 
 785 
 
 
 
 
 
 
 o From calculations of Atwater and Bryant (1906). 
 
no BULLETIN OF THE BUREAU OF FISHERIES. 
 
 A comparison of the fuel values of the mussel and oyster based on the total weight 
 of waste and edible portions shows that the value of the mussel as a food is three times 
 greater than that of the oyster. The ratio between the fuel values of the edible portions 
 of these two shellfish is more nearly equal, but the mussel in this case is superior to the 
 oyster by 65 calories per pound. The fuel values of the mussel and long clam are 
 about the same. Compared with lean beef we might say that s}4 pounds of mussels 
 in the shell, or 2^ pounds of meats and liquor in their natural proportion, are equal in 
 food value to i pound of beef. 
 
 As a food material, therefore, from the standpoint of chemical composition and 
 nutritive value, the mussel is far superior to the oyster, is equal to the long clam, and 
 has about one-third the value of lean beef. 
 
 MUSSELS A CHEAP FOOD. 
 
 Measured by the fourth standard, economy, we again find the mussel taking high 
 rank among food materials. It is widely distributed, extremely abundant, and easily 
 obtained. Mussels abound in the bays and estuaries of our Atlantic coast from North 
 Carolina northward and on our Pacific coast from Alaska to San Francisco. They 
 grow in great beds, often acres in extent, on the surface of mud or sand extending out 
 from between tide marks to several fathoms of water. Plate xxiv, figure i, is a 
 view of an exposed mussel bed at Menemsha Pond, Marthas Vineyard, Mass. This 
 bed is but two years old and represents hundreds of tons of valuable food. 
 Mussels are also found growing in great abundance out in the deeper waters. On one 
 occasion in Vineyard Sound, not far from Robinsons Hole, the steamer Fish Hawk 
 dredged up a beam trawl full of them, a quantity approximating a ton or more. A 
 resident of Pawtucket, R. I., writes that there are places in Narragansett Bay where a 
 man could obtain 50 bushels a day for the whole season if he had a partner to receive 
 and dispose of them. Under these conditions he considers 35 cents a bushel a reason- 
 able price to ask. The total supply of New York City, which amounts to 75 barrels of 
 mussels in the shell and 400 gallons of the pickled variety per day, is furnished chiefly 
 from the bays bordering Long Island. The man who provides nearly this whole 
 supply informed me that the quantity of mussels is far in excess of the demand. 
 
 As has already been shown, the mussel breeds at an almost inconceivable rate 
 and grows very rapidly. Even if the demand should grow to exceed the supply from 
 the natural beds it would be an easy matter to meet the increase by means of cultiva- 
 tion. The methods which may be utilized for this purpose are discussed in another 
 chapter. 
 
 The question of real economic importance to the consumer of food is the ratio 
 between the cost of a given food and the amount of nutriment it supplies. Milner 
 (1903) groups food materials into three classes: (i) Cheap, those which furnish more 
 than 1,900 calories energy for 10 cents at ordinary prices; (2) Medium, those which 
 furnish 800 to 1,900 calories energy for 10 cents; and (3) Expensive, those furnishing 
 less than 800 calories energy for 10 cents. A bushel of mussels weighs about 70 pounds. 
 
FOOD VALUE OF SEA MUSSELS. Ill 
 
 At 35 cents a bushel the rate would be half a cent per pound, or lo cents for 20 pounds. 
 In table 8 we find the fuel value for each pound of mussels in the shell to equal 140 
 calories energy. 20X140 = 2,800 calories energy, the amount 10 cents would purchase 
 at 35 cents per bushel. This, however, is calculated on the wholesale price. The 
 retail cost would probably be double this amount. Consequently, our fuel value 
 should be cut in half, making 1,400 calories energy the purchasing value of 10 cents 
 at retail rates. Thus the calculation on wholesale prices places the mussel in the class 
 of cheap foods. The calculation on retail prices puts it among the cheaper of the 
 medium-priced foods, such as beef flank, neck and shank, milk, beans, and turnips. 
 
 To thousands of families who live near the coast, the mussels are to be had for the 
 slight effort required to gather them, and yet up to the present time all this vast wealth 
 of food has been ignored and wasted. This, too, where families in easy reach of a rich 
 supply of the shellfish are facing poverty. 
 
 PRESERVATION METHODS. 
 
 At the present time there is great need for methods of preserving perishable foods 
 in such a manner as not to injure their palatable flavor and nutritive qualities or greatly 
 increase the price at which they may be sold to the consumer. Especially is this true 
 for fishery products, which spoil very quickly after removal from the water. The 
 decomposition which sets in so rapidly is caused by the presence of bacteria, which 
 multiply with great rapidity, the rate of putrefaction progressing in direct proportion 
 to their increase in number. 
 
 To preserve fishery products, then, it is necessary to keep them free from the 
 action of bacteria, and this may be accomplished by eliminating one or more of the 
 three conditions on which the life and growth of the organisms depend — ^namely, heat, 
 moisture, and oxygen. Cold storage deprives the organisms of sufficient heat for 
 growth, desiccation takes the needed moisture from them, and canning at high tem- 
 peratures destroys the germs present and, furthermore, excludes the air required for 
 growth. Antiseptics, such as salt, vinegar, and boracic acid, are employed to prevent 
 the multiplication of bacteria. All of these methods are applicable to the mussel. 
 
 The sea mussel is of all the shellfish particularly adapted for canning. Unlike the 
 oyster, it remains tender and retains its full flavor when subjected to the high tem- 
 peratures necessary to prepare it in this way. The process which has been devised as 
 most feasible is as follows : 
 
 The mussels when taken from the collecting boats are rapidly picked over by hand 
 to eliminate any dead or unhealthy ones which may be present, as well as the coarse 
 adhering debris. Then they are placed in a cleaning apparatus, such as is shown in 
 figure 2. It consists of a rectangular box 2 by 2 by 3 feet, which revolves on its long 
 axis. The ends of the box are of solid yellow pine and are firmly held in place by four 
 pairs of braces 3 feet long, 2 inches wide, and ;^ inch thick. Three sides of the box are 
 
112 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 inclosed with ^-inch mesh galvanized wire netting. The fourth side has a door 8 inches 
 wide, running the length of the box. The door is clamped firmly in place by means of 
 a lever, which is swung over it. The rest of the side is filled in with parallel strips of 
 wood placed one-half inch apart. The projecting ends of the axis rest on the walls 
 of a trough i yi feet deep, in which there is running sea water. A crank at one end serves 
 as a means to rotate the cage. 
 
 About I bushel of mussels is placed in this cleaning apparatus, which is set in rota- 
 tion at the rate of 30 revolutions a minute for fifteen minutes. The treatment cleans 
 off from the shells all clinging sea weeds, sand, and debris, besides breaking open the 
 
 Fig. 2. — Apparatus for cleaning mussels preparatory to canning or other preservation process. (Drawn 
 for the author by Prof. L. C. Harrington.) 
 
 shells of dead mussels and washing away the injurious substance contained within them. 
 In the experimental work this method of cleaning mussels proved very effective. For 
 cleaning on a commercial scale the device may easily be constructed on larger dimen- 
 sions and operated by means of steam or water power. 
 
 After this treatment the mussels are removed and rinsed off with clean water. 
 They are placed in a chest and subjected to live steam for from five to ten minutes, or 
 until the shells begin to open. They are next emptied out into shallow pans to cool 
 and the natural liquor which has escaped into the chest is preserved in a separate dish. 
 
FOOD VALUE OF SEA MUSSELS. 
 
 113 
 
 As soon as they are cool enough to be handled, the mussels are shucked and the horny 
 "beard" removed, the meats and liquor being preserved in separate dishes. 
 
 While the liquor taken from the steam chest and that taken from the mussels 
 during the process of shucking is filtering through a fine-meshed cloth, the mussel meats 
 are packed in glass jars or bottles. The filtered liquor is brought to a boil and 2 ounces 
 of salt are added for each gallon. The jars containing the meats are then filled with 
 the boiling liquid and sealed. To insure complete sterilization, the sealed jars are 
 placed in a steam chest and subjected to 5 pounds pressure for fifteen minutes. They 
 are allowed to cool down slowly and when the temperature has fallen to about 100° F. 
 they are removed and set aside for future use. 
 
 Persons wishing to can mussels for use in their own homes and who lack the facilities 
 described in this process, may do so by modifying the method in the following way: 
 After thoroughly cleaning the outsides of the mussels by means of a stiff-bristled brush, 
 rinse them in clean water and place them in a large, closely-covered kettle with a little 
 water covering the bottom — about one cup of water to each gallon of mussels. Place 
 on the stove and bring to a boil, continuing the cooking for about fifteen minutes or 
 until the top shells have opened. Pour out the liquor that has collected in the bottom 
 of the kettle and preserve it in a separate dish from the mussels. Shuck the mussels, 
 being careful to remove the byssus or horny tuft of threads growing out from the base 
 of the foot. While the liquor is filtering through a fine-meshed cloth pack the meats 
 in pint or half-pint glass jars of the ordinary household type. To each quart of the 
 filtered liquor add one heaping teaspoonful of salt and bring it to a boil. Pour the 
 boiling liquid over the mussel meats, filling the jars to the brim, and then quickly clamp 
 or screw on the lids. The jars should next be placed in a large vessel, such as a wash 
 boiler, containing boiling water, and left to boil for at least half an hour. At the end 
 of this time the vessel with its contents should be removed to the back of the stove 
 and allowed to cool. As soon as convenient the jars may be removed and the tops 
 tested to see that they are sealed air tight. Treated in this manner, the mussels ought 
 to keep for many months and preserve their natural flavor. When desired for use on 
 the table they may be prepared according to almost any of the methods employed in 
 preparing the fresh mussels for food. 
 
 At the present time, in the United States, the pickling of mussels is the only form 
 of preservation in use. As an article of trade they are known only to New York City 
 and vicinity, one man supplying most of the demand with 400 gallons per day. They 
 are eaten both by Americans and foreigners. The process for preservation by pickling 
 involves the use of vinegar and spices in various proportions according to individual 
 fancies. In my own experience I have found the following formula most satisfactory 
 in results : 
 
114 BULIvETlN OF THE BUREAU OF FISHERIES. 
 
 After thoroughly washing the mussel shells in the cleaning apparatus already 
 described, the mussels are placed in a steam chest for about ten minutes, or until the 
 shells have opened. They are then shucked, the liquor and meats being preserved in 
 separate vessels. Care should be taken to see that the horny filament or "beard" is 
 removed from the base of the foot. For each quart of natural liquor there is added 
 I pint of vinegar, Yz ounce of allspice, X ounce of cinnamon, % ounce of cloves, % ounce 
 of salt, and i small red pepper. The mixture is allowed to simmer upon the stove for 
 fifteen minutes and is then poured over the meats. After standing about twenty-four 
 hours the meats are removed from the spiced liquor and are neatly packed in bottles 
 or fruit jars. The liquor after being filtered through a fine-meshed cloth, to remove 
 the undissolved spices and sediment that is formed, is heated to boiUng and poured 
 over the meats until the jars are brimming full. The jars are sealed air tight and placed 
 in a steam chest, where they are subjected to 5 pounds steam pressure for fifteen 
 minutes. 
 
 After this treatment they will remain in a good state of preservation for about two 
 years. If the pickled mussels are desired for immediate consumption, it is not necessary 
 to seal them up in jars. They may be kept a week or more in open tubs without dete- 
 riorating. If kept much longer than this, they gradually turn dark and fall to pieces. 
 A New York dealer told me that he was able to sell pickled mussels in the tub at 35 
 cents per gallon, but this gave him very little profit. 
 
 The preservation of mussels by means of desiccation is a problem to which I 
 have devoted considerable attention. So far the efiforts have been hardly successful 
 enough to make mention of them in this report. A few words concerning the difficulties 
 involved in the process, however, and some observations may be of value. The prob- 
 lem to solve in drying mussels for food is to regulate the process, so that the flavor of 
 the meats is not impaired nor the appetizing odor lost. 
 
 The plan originally employed was to clean the mussels, steam and shuck them by 
 the method already described, and transfer the meats to an artificial dryer, which con- 
 sisted of a large chamber, 3 by 5 by 6 feet, tapering off at the top into a flue. Two 
 drawers with galvanized wire bottoms extended into this chamber. A current of air 
 was forced by means of a 24-inch fan over a hot radiator into the bottom of the cham- 
 ber, from whence it passed upward through the meshed drawer bottoms and over the 
 substance to be dried. The temperature of the air as it passed over the drying flesh 
 was 50° C, or 122° F. Material subjected to this treatment dries very rapidly, even in 
 the very humid atmosphere of Woods Hole, Mass. In from seven to twelve hours 
 mussel flesh treated thus will lose 70 per cent of its weight. The accompanying table 
 of 12 experiments indicates that after seven hours' drying most of the water which it 
 is possible to extract by this method has been removed. 
 
FOOD VALUE OF SEA MUSSELS. 
 Tabl,b 9. — Showing Loss op Weight in Mussels Due to Drying. 
 
 115 
 
 Date. 
 
 Weight of 
 flesh. 
 
 Time in 
 dryer. 
 
 Weight after 
 drying. 
 
 Per cent of 
 loss. 
 
 Per cent re- 
 maining. 
 
 1907. 
 August 28 . . 
 
 Ounces. 
 
 10 H 
 
 29 
 
 2 4 -"4 
 65 
 
 «42 
 
 los 
 47 
 37 
 24 
 30 
 
 Hours. 
 
 13 
 IS 
 
 12 
 14 
 20 
 
 ?s 
 17 
 19 
 
 20 
 22 
 
 Ounces. 
 
 7U 
 
 6H 
 23 H 
 
 gH 
 36 '4 
 14 H 
 11 H 
 
 6H 
 
 69.4 
 79.5 
 70.83 
 
 73- 71 
 72. 13 
 64.04 
 76. 79 
 65.48 
 69-95 
 68. 24 
 71.84 
 75.00 
 
 30.60 
 20.50 
 29. 17 
 
 26. 29 
 27.87 
 35.96 
 
 
 
 1908. 
 
 
 July 12 
 
 
 
 3452 
 30.0s 
 31.76 
 28.16 
 25.00 
 
 August 10 
 
 Do 
 
 
 August 28 
 
 
 Total 
 
 499?^ 
 
 i-iei 
 
 149K 
 
 1 
 
 
 
 
 o Had been salted down 15 hours. 
 
 ' Average length of time in the dryer. 
 
 The product of this treatment is a brown brittle substance with an unappetizing 
 look and odor. The appearance is greatly improved by passing the material through 
 a sausage grinder, which breaks it up into a mass of brown granules. In this condition 
 it looks well when put up in glass jars or fiber-ware packages. The only remaining 
 objection to it is an offensive alkaline odor. In attempts to eliminate this disagreeable 
 quality I have treated both the raw and cooked flesh with salt, with vinegar, and with 
 hydrochloric acid in various proportions and for various periods of time preliminary to 
 the drying, but without success. The purpose of using the acid, which was in very 
 dilute solutions, was to neutralize the alkaline compounds as fast as they were formed. 
 Dried mussels which had been soaked in a 0.2 per cent solution of hydrochloric acid 
 for two hours before desiccation were rendered remarkably free from any bad odor. 
 After being bottled up for a few weeks, however, they acquired the smell so character- 
 istic of the dried material. 
 
 In spite of this offensive property the dried mussel can be used in preparing a very 
 palatable soup or chowder. A better smelling variety will have to be produced, how- 
 ever, before there can be a possibility of attaching commercial importance to it. 
 
 The chief trouble with this process is that the drying is accomplished at a high 
 temperature, where chemical changes within the food material are accelerated, causing 
 the production in large quantities of undesirable substances. This difficulty is removed 
 by means of an improved method of desiccation devised by Shackell (1909). Briefly, 
 this consists in freezing the flesh, and drying it, while still in the frozen condition, in a 
 vacuum. At this low temperature chemical changes practically cease and with the 
 extraction of moisture a very stable substance is secured which will withstand all ordi- 
 nary temperatures. Mussel flesh treated by this method shows remarkable properties. 
 It retains the color and form of the fresh material; it is light and porous and can be 
 easily crushed between the fingers. In air-tight bottles it may be preserved indefinitely. 
 
Il6 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 A sample of mussel thus prepared, after having been kept a month, was placed in a 
 small dish of water. The dried material rapidly absorbed moisture and at the same 
 time the natural juices dissolved out into the water, giving it the characteristic opa- 
 lescent color of fresh mussel liquor. The odor was that of perfectly fresh mussels, and 
 when made into soup the aroma and flavor were those of cooked fresh material. This 
 method of preservation is ideal but for one reason — the high cost forbids its use com- 
 mercially. The inventor of the method is working to overcome this disadvantage. 
 
 COLD STORAGE. 
 
 The mussel is not well adapted to the method of preservation by means of cold 
 storage. The writer wishes to make this statement with reserve, however, since his 
 experiments in this respect have been very limited. Attempts to keep mussels fresh in 
 an ice chest for more than twenty-four hours met with failure. They appeared to 
 live no longer in the cold than in the open air. Decay did not seem to be retarded by 
 the lower temperature of the ice box. This fact was a matter of complaint made by a 
 New York dealer who wished to develop a market for mussels inland. I was informed 
 that it would be possible to develop quite a trade in mussels if a method for preserving 
 them in the fresh or living condition could be devised. At present I can only suggest 
 a probable solution of the problem; that is to reduce them to a freezing temperature 
 and ship them in a double walled carrier having a vacuum between the walls. The 
 vacuum being a nonconductor of heat insures the continued low temperature of the 
 mussels and does away with the surplus weight of ice usually employed in cold-storage 
 transportation. The mussels preserved in this manner would have to be used almost 
 immediately after removal from the carrier. Further mention of this method of preserva- 
 tion will be found in my conclusions and recommendations. 
 
 RECIPES FOR COOKING SEA MUSSELS. 
 
 CREAMED MUSSELS. 
 
 Thoroughly wash the mussels and place them in boiling water until the shells begin to open. Pour 
 off the water quickly, take out the "beard" or byssus, and remove the meats from the shell, preserving 
 the liquor in a separate dish. For each cupful of chopped meats make one cupful of cream sauce, 
 which is prepared by melting in a saucepan one tablespoonful of butter and stirring with it one table- 
 spoonful of flour; cook, being careful not to brown it; then stir in slowly one-half cupful of mussel 
 liquor and one-half cupful of milk or cream and season with pepper and salt to taste. Continue to cook 
 until it is thick and creamy, stirring all the time; add the mussels just before serving. Pour the mixture 
 over small pieces of toast laid on the bottom of the dish. 
 
 FRIED MUSSELS. 
 
 After thoroughly cleaning the outsides of the mussels boil them until the shells begin to open. 
 Take out the " beard" and remove the meats from the shell. Season with salt and pepper, then roll in 
 cracker or bread crumbs, dip in egg beaten up in milk, and roll again in the crumbs; fry quickly in hot 
 fat; drain on paper as fast as taken up. Serve hot, garnished with slices of lemon. Have them as free 
 from grease as possible. 
 
FOOD VALUE OF SEA MUSSELS. 117 
 
 MUSSEI^ CAKES. 
 
 Clean and scald the mussels as directed above, beard, and remove the meats. To one pint of 
 chopped mussel meats add two eggs, one-half cupful of milk, two teaspoonfuls of baking powder, and 
 a pinch of salt. Stir in enough flour to make the mixture a little thicker than pancake batter and fry. 
 
 MUSSEL CHOWDER. 
 
 Clean and scald the mussels as directed above, take out the beard, and remove the meats, preserv- 
 ing the natural liquor in a separate dish. To a quart of the meats take a quarter pound of salt pork; 
 cut it into small squares and fry to a brown in the bottom of the kettle. At the same time add three or 
 four sliced onions and cook until the pork is well tried out; then add the mussel liquor, mixed with an 
 equal quantity of water, and when it comes to a boil add six finely chopped or sliced potatoes and 
 boil in a closely covered dish until the potatoes are done; then add the mussels with one quart of boiUng 
 milk, season with pepper and salt to taste, and serve. 
 
 MUSSEL CROQUETTES. 
 
 Clean and scald the mussels as directed above, beard, and remove the meats from the shell. Chop 
 up one pint of meats, moisten with a thick cream sauce, add one teaspoonful of chopped parsley and 
 bread or cracker crumbs sufficient to make the mixture firm enough to shape, season with salt and 
 pepper. Let the mixture get cold, then shape into croquettes and fry in hot fat, in a frying basket if 
 available; drain and serve on a hot napkin. 
 
 MUSSEL FRITTERS. 
 
 Two eggs, one tablespoonful of oil, one cupful of flour, one-half cupful of mussel liquor, pinch of 
 pepper and salt, tablespoonful of lemon or vinegar, one cupful of chopped mussel. Have the mixture 
 quite thick and drop from a tablespoon into hot fat and fry until an amber color. 
 
 MUSSEL PATTIES. 
 
 Cut one quart of scalded mussels into small pieces and stir into one cup of rich drawn butter based 
 on milk, season to taste, cook five minutes, fill the patty cases, heat two minutes, and serve 
 
 MUSSEL SOUP. 
 
 Clean and scald the mussels as directed above, beard, and preserve the meats and liquor in separate 
 dishes. To one pint of the liquor add an equal quantity of water; season with pepper, mace, and salt, 
 and boil five minutes. Then put in the mussels, either whole or minced, and boil for five minutes with 
 the vessel closely covered. Then add a pint of milk thickened with a little flour and butter or fine 
 cracker crumbs. The addition of a little chopped celery and onion improves the flavor. 
 
 ROASTED MUSSELS. 
 
 Wash the shells thoroughly with a brush and cold water. Place them on a pan and bake in a hot 
 oven until the shell opens. Remove the upper shell carefully, so as not to lose the liquor, and arrange 
 them "on plates. On each mussel place a piece of butter and a little pepper and salt. Do not roast too 
 long. 
 
 STEAMED MUSSELS. 
 
 To a gallon of thoroughly washed mussels, add one cup of water and boil in a closely covered vessel 
 for ten minutes or until the mussels on top are well opened. Then pour off the water and place the mus- 
 sels in a large dish on the center of the table. Serve to each person some melted butter to which may 
 be added vinegar and pepper to taste. The mussels may be removed from the shell, bearded, and, 
 held by the foot, dipped into the butter and eaten. 
 
Il8 BULIvETiN OF THE BUREAU OF FISHERIES. 
 
 The French people are noted for their excellent preparations of mussels for the table. 
 The characteristic feature of nearly all their methods is to serve them on the half shell. 
 From Audot's "La Cuisinere de la Ville et de la Campagne" I have taken the following 
 recipes : 
 
 MUSSELS (ENTRIES). 
 
 Choose mussels which are fresh, heavy, and of medium size, scrape and wash them through sev- 
 eral waters. (In order that one may have no fear of them, it is necessary to cleanse them for five or six 
 hours in water which is renewed several times. Not only are they able to reject the impurities within 
 them, but they gain in quality. It is necessary to avoid using them from April to September, during 
 which time they are apt to be unhealthy.) 
 
 A la marinibre. — Having cleaned the mussels well, place them in a saucepan with some white wine, 
 a glass to 4 quarts, or else a spoonful of vinegar, some slices of carrots, onion, and parsley chopped fine, 
 thyme, clove of garlic, a little salt and pepper, 2 cloves, and a piece of butter the size of an egg. Place 
 the saucepan on a good fire, keeping it covered from the first to make the shells open. Stew continu- 
 ously until the shells have opened, when the mussels are done. From each remove one of the shells 
 and take out the little crabs which are found in them, but which are not injurious in any way; they are 
 found present principally during the months of the year which do not contain the letter "r." When 
 the mussels have thus been opened, stew them a while (stirring or shaking to prevent them from sticking 
 to the saucepan) and then turn them into a large, deep dish with a quart of their dressing strained 
 clear. The remainder of this dressing makes a very agreeable onion soup. 
 
 A la poulette. — Take up quickly some of the prepared mussels (steamed and prepared on the half 
 shell), as they are called, and make a sauce with a piece of butter, a pinch of flour, a little of their liquor, 
 and the yolks of eggs, if these are desired. Turn this upon the mussels and serve. 
 
 A la bichamel. — Pour over the mussels a bechamel sauce in place of the sauce poulette. 
 
 be;chamel s.\uce. 
 
 Melt a piece of butter (about i ounce) and mix well with it a spoonful of flour and some salt and 
 white pepper. Moisten it with a glass of milk, a little at a time with constant stirring; let it boil, being 
 continually stirred. At the same time warm over that which you wish to serve with the sauce. To 
 make it more elaborate, place in a saucepan some butter, slices of onion, a carrot, a bunch of parsley, 
 some mushrooms, and place it on a fire. Moisten with someTaoiling milk, adding a little at a time with 
 constant stirring; add some salt, white pepper, and nutmeg, and stir until it boils. Allow it to cook very 
 slowly for three-quarters of an hour, then strain it through a colander. In a saucepan make a light- 
 brown butter sauce with 3 spoonfuls of flour and turn into it the milk broth; let it boil three minutes. 
 
 Attention should be called to the fact that Audot's precaution to avoid eating 
 mussels between the months of April and vSeptember does not apply to all parts of the 
 world. On our northern Atlantic coast the months between April and September are 
 the very months when the mussels are best for eating purposes, while during the fall and 
 early winter they are unfit for use. The explatiation of this is that the mussels of France 
 breed in the early spring while these on our coast breed in the late summer and fall. 
 After spawning the mussels become sickly and great numbers of them die. A more 
 general way to state the precaution is : Avoid eating mussels from a given locality dur- 
 ing the four months following their spawning. At the end of this period they again 
 become fat and healthy. 
 
FOOD VAIvUE OF SEA MUSSELS. I19 
 
 CULTIVATION OF MUSSELS. 
 
 In Europe, where there is considerable demand for mussels as food and bait, it long 
 ago became necessary to cultivate them artificially on a large scale. Two methods were 
 devised. One may be termed the buchot system or French method, and the other the 
 Ued system or British method. The buchot system is apparently much the older and 
 its history, although published in many French and English periodicals, is so interesting 
 that it ought to be recorded again briefly at this point. 
 
 Strange as it may seem, this French system of culture was invented by an Irish- 
 man named Walton who was the sole survivor from a shipwreck in the Bay of Aiguillon 
 near the village of Esnandes some seven or eight centuries ago. Authors disagree as to the 
 exact date. Quatrefages (1854) states that it was in the year 1035, Bertram (1865) 
 says 1 135, while Coste (1883) puts it at the close of the year (1235). Walton was kindly 
 received by the French fishermen, with whom he decided to make his home, although 
 the prospects of making a good living were not very bright. 
 
 Up to the time of Walton's arrival the inhabitants of the coast had been unable to get 
 much sustenance from the sea, but the newcomer was ingenious and was not long in origi- 
 nating a means for earning a livelihood from this source. His first step was to explore 
 an immense lake of mud which was in the locality and there observing that large num- 
 bers of land and sea birds were in the habit of skimming over the water at twilight, he 
 determined to catch them as an object of trade. For this purpose he devised a large 
 net, the "alluret," which was between 330 and 430 yards long and 10 feet in height, 
 fastened in a vertical position to stakes driven into the mud to a depth of 3 or 4 feet. 
 Birds fl3ang into its meshes were entangled and held securely. Shortly after beginning 
 his bird-catching business, Walton discovered that young mussels in great numbers were 
 collecting on the submerged stakes of his net. He also observed that mussels sus- 
 pended for some distance over the mud grew to a larger size and were better flavored 
 than those upon the mud. He experimented by putting down many more stakes, 
 which in turn became covered with growing colonies of mussels. Continuing his experi- 
 ments he was soon convinced that the young of native mussels could be easily gathered 
 and profitably raised in artificial reservoirs. 
 
 The buchot system of mussel culture that was finally established by Walton is still 
 followed and has proved a lasting reward and blessing to that locality, where at the pres- 
 ent time buchots extend for miles along the coast and give support to several thousand 
 inhabitants. In 1905 the village of Esnandes alone marketed 215,253 bushels of mussels, 
 valued at $112,433. The total number of mussels cultivated on the French coast in 
 1905 is estimated at 425,492 bushels, valued at $222,439. 
 
 Walton's buchots, or wooden inclosures for the artificial rearing of mussels, were 
 made V shaped, with the apex pointing out to the sea, the purpose of this arrangement 
 being to protect the structure from the destroying action of the wind, waves, and ice. 
 Each wing of the V consisted of a row of stakes placed about 2 feet apart and interlaced 
 with a meshwork of flexible willow or chestnut branches some 12 to 18 feet long and 
 
I20 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 2 inches in diameter at the larger end. The stakes were trunks of trees, ^ to i foot in 
 diameter and from 12 to 15 feet long, driven into the mud for about one-half their length. 
 The meshwork covered the stakes to within 8 inches of the bottom, the space being left 
 to allow free circulation of water, so as to prevent the deposition of mud at the base of 
 the stakes. Each horizontal line of branches was tightly woven to the stakes to pre- 
 vent slipping up or down. They were arranged about 20 or more inches apart, because, 
 if brought together closer than that, they were apt to collect mud and cause deposits 
 that would interfere with navigation and perhaps seriously injure the apparatus itself. 
 
 The length of wings to a buchot at any particular place depended, as now, on the 
 nature of the bottom on which they were constructed. At present they occupy about 
 one-fourth of the distance between the extreme limits reached by the water at high and 
 low tides. In the Bay of Aiguillon they are now constructed about 250 yards long, and 
 according to Herdman (1894), who has made an extensive study of this region, are no 
 longer arranged in the V form, but in parallel rows about 30 yards apart at right angles 
 to the shore. The buchots are practically made up of two divisions, one for collecting 
 spat and the other for the growth and fattening of the mussels. 
 
 Five series of buchots may be included in these two divisions: (i) Buchots d'aval, 
 (2) buchots batisse, (3) buchots du bas, (4) buchots batards, and (5) buchots d'amont. 
 
 The buchots d'aval are out in the deep water, sometimes 3 miles from high-water 
 mark, and are exposed only at the lowest tides. They are composed merely of solitary 
 stakes placed about i foot apart. They serve to catch the spat and constitute a most 
 favorable place for the early growth of the mussels, since it is necessary for the 
 young to be protected from long exposure to the sunlight or extreme cold. The spat 
 collects on these stakes during February and March. By July the young mussels have 
 attained the size of a haricot bean. 
 
 At this time the seed mussels are scraped off the piles by means of hooks fastened 
 in a handle, are collected in baskets, and transferred to the next zone of weirs, the buchots 
 batisse, toward shore and ordinarily uncovered after high tides. The parcels of young 
 mussels are fastened by means of old netting to the branches, where, before the netting 
 decays away, they become firmly attached by their byssal threads. When the mussels 
 have grown so large as to be crowded on the wickerwork, they are thinned out by removing 
 the larger ones to the next higher buchots, and so on from one section to the other, each 
 time transferring the mussels nearer the shore. The mussels are attached by the same 
 operation already described, but are not wrapped so carefully since their size is such as to 
 enable them to be more securely fastened without help of the netting. The work of 
 transferring from one buchot to another goes on day and night whenever low tide permits it. 
 
 After about one year's treatment under these conditions the mussels attain market- 
 able size, which is between i J and 2 inches in length. Before being offered for sale, those 
 that have reached the desired size are transplanted to the highest row of buchots, the 
 buchots d'amont. In this location, although left dry twice each day, they thrive well 
 and can be easily handled when desired for market. The mussels on these upper rows 
 become inured to exposure and consequently keep longer and fresher than those from 
 
FOOD VALUE OP SEA MUSSELS. 121 
 
 the lower rows. The poorest of cultivated mussels are considered superior to the best 
 mussels grown under natural conditions. 
 
 To traverse the soft mud from one buchot to the other Walton devised the "aeon," 
 a characteristic mudboat still used by the bucholeurs. Herdman (1894) describes it as 
 follows : 
 
 The "aeon" is composed of a plank forming the bottom and bent up in front to make a flat prow. 
 The sides and stern are each made of one piece of wood, sometimes the sides are of two planks each. 
 The size is 9 or 10 feet in length, from 2 feet to 2 feet 6 inches wide, and about i foot 6 inches deep. 
 There is a shelf at the stern, a narrow thwart close to the bow, and a small wooden stool in the middle 
 of the floor; these with a wooden paddle and a short pole complete the equipment. The boatman in 
 using the "aeon" faces the bow, grasps the sides about the middle firmly with both hands, rests his 
 left knee on the floor of the boat, and putting his right leg (encased in a long sea boot) over the side, 
 he plunges it into the mud and pushes it onward. He is able to propel it at a great rate over the soft 
 mud, and when he gets to a channel of water where the "aeon" floats he works with paddle or pole 
 until he again reaches mud and is able to use his foot. 
 
 The British method of mussel culture, briefly, is to collect young mussels from salt 
 water and transfer them to artificial beds in favorable localities. These are generally 
 situated in estuaries where the water is brackish and where they are not exposed at 
 low tide, both of which conditions are supposed by many to favor growth and fattening. 
 Others believe that the presence of fresh water is injurious to the young shellfish and of 
 no advantage to the full-grown individuals. To support their views they point to the 
 large beds of healthy, uniform-sized individuals in regions far removed from the influence 
 of fresh water. Harding (1883) believes that the spat will not mature in anything but 
 pure sea water, but that for fattening full-grown mussels brackish water of the density 
 1. 014 is most suitable. It has been estimated that the average yearly yield of an acre 
 of such mussel beds is 108 tons, worth at least $262. 
 
 Careful cultivators observe several rules in planting mussels. They may be planted 
 on almost any natural bottom, but rich estuarine flats where there is plenty of sand and 
 gravel covered with mud rich in diatoms, infusoria, and spores of algae is considered the 
 ideal situation. They are placed in positions where they are not exposed to dangers from 
 floods, gales, shifting sands, or frost. The beds are so placed that they will not be un- 
 covered long at low tide nor where silt is likely to deposit upon them. Should this evil be 
 discovered the bed is immediately transplanted to a better situation. In planting the 
 beds care is taken not to place the individuals so close together that one will come to 
 lie on another and thus cause a too crowded condition. 
 
 For collecting the mussels a rake or dredge is used, the former instrument being 
 considered better than the latter for the reason that it does not crush the shells nor cause 
 sand to shift over the bed. In size it has a breadth of about 18 inches, with the teeth i 
 inch apart. It is fixed to a pole 20 to 25 feet long and has a wire net bag behind it for 
 holding the catch. The large and small mussels are separated by means of a riddle, 
 which is an instrument having a i-inch iron mesh. The bunches of various size mussels 
 are first separated by hand and then sifted, or riddled. The large and small mussels 
 thus divided are then placed in separate beds or the large ones utilized for bait. 
 
122 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 Other methods of myticulture are followed in certain localities. Goode (1887), 
 describing some of the European methods, says: 
 
 In the North Sea these [spat collectors] consist of large numbers of trees, from which the smaller 
 branches have been cut, and which are planted in the bottom of the sea at such a distance from the 
 shore that their upper portion is partially laid bare at low water. After four or five years they are 
 raised, stripped, and replaced by others. In the Bay of Kiel, Germany, alone about 1,000 of these trees 
 are annually planted and about 1,000 tons of mussels are brought on the market. Bad seasons occur, 
 however, both with respect to quality and quantity, owing to various causes. In the Adriatic the 
 mussels are raised on ropes extended between poles rammed into the ground. The ropes are raised and 
 stripped once in eighteen months. 
 
 The question now arises, Which is the better method for artificially propagating 
 mussels on our coast ? This depends on two factors; (i) the quality of mussels produced, 
 and (2) the actual expense of propagation as compared with the financial return. 
 Though I unfortunately can not answer this question now, I can throw a little light on 
 it from the experience of others. In France, where labor is cheap, the buchot system 
 is most profitable, while in England, where the cost of labor is much higher and where 
 favorable localities for buchot culture are few, the bed system has to be employed. 
 That the buchot method of culture is not practicable for the vScottish coast is very 
 evident from the extensive report of Fullarton (1891), whose conclusion I quote: 
 
 The buchot experiment, therefore, does not promise to yield in Scotland the same good results as 
 in France. This is due to the character of the mud along our shore, to the climatal conditions of our 
 Scottish waters, and the influence of these on animal life. But the financial aspect of the question, as 
 shown above, is absolutely fatal to the system. I can not conceive what modifications of the buchot 
 system would be likely to yield results which would benefit the fishermen of Scotland, nor mitigate in 
 any important degree the mussel famine; while the bed system only requires to be developed in suitable 
 localities in order that fishermen may obtain an ample supply of bait at a cheap rate and on sound 
 financial principles. 
 
 Calderwood (1895) states that the buchot system of culture has been tried on a small 
 scale at five different places in Scotland, and in every case was a failure. At Little 
 Ferry the mussels were washed from the structures by gales; at Tain one buchot was 
 covered with shifting sand, while another erected in an unfortunate position yielded 
 little return. At Inverness the cost of handling the mussels was fotmd prohibitive 
 and at Montrose the system was found unsatisfactory because the mussels fell from the 
 laths, which were used instead of branches. Where the cost of building material and 
 labor are high, the buchot system will be found unprofitable. 
 
 Herdman (1894) believes that mussels grown on buchots are no better than those 
 grown on beds, and thinks the buchot system is necessary only in localities where the 
 mud is soft and so constantly depositing as to prohibit a bed of mussels from being estab- 
 lished. Lrcbour (1907), describing the mussel beds of Northumberland, believes that 
 the bed system is the only suitable method of cultivation on the coast and that the 
 buchot system is not a practical one to apply even at Budle Bay and Holy Island, 
 which regions are best adapted for their use. 
 
 In view of the facts just stated, and especially in consideration of the high cost 
 ol" building material and of labor in the United States, the prospects are very poor for 
 
FOOD VAI^UE OF SEA MUSSEI.S. 1 23 
 
 successfully cultivating mussels by the buchot method on our shores. No serious 
 objections having yet been found to the bed system, we are left to utilize that method 
 with better hopes of success, unless in the meantime a better method is devised. 
 
 POISONOUS MUSSELS. 
 
 Mussels, like oysters, clams, and other shellfish, are subject to contamination from 
 parasites, bacteria, and the ptomaines generated by these, which render them a dan- 
 gerous food unless selected with proper care. Cases of serious illness from eating 
 poisonous mussels are known and a number of persons have died from the effects. The 
 same is true of oysters and clams, and inasmuch as the symptoms in all the cases are 
 similar, there is nothing here to indicate that the mussels are not just as safe a food 
 as the other shellfish when gathered with the same precautions. If they are collected 
 from pure water and eaten in a fresh condition, they are a wholesome food. It some- 
 times happens, however, that the individual is peculiarly susceptible to poisoning from 
 shellfish, and such persons I would advise to abstain from eating them. 
 
 The most common cases of poisoning from mussels and other shellfish are due to 
 ptomaines, which are poisonous substances resulting from the action of micro-organisms 
 upon the animal tissues. Their formation usually, although not always, accompanies 
 putrefaction and they are said to be most abundant in its early stages. It is therefore 
 safest to prepare for the table only shellfish that are in a healthy, living condition. 
 Dead mussels should never be purchased. Good specimens are free from any stale 
 odor and do not remain with the shells open after being slightly irritated. They defy 
 all efforts to open their shells until the muscle which holds them shut is cut. 
 
 Dangerous intestinal troubles, followed by eruptions on the skin, have been known 
 to result from eating apparently fresh mussels. Various explanations have been offered 
 to account for these effects. Goode (1887) states that the Alaskan Indians, recognizing 
 this fact, eliminated it by removing the byssus or beard whenever it had a greenish 
 color, which was a sign that the animal had been feeding upon poisonous material. 
 Better evidence, however, shows that these evil effects come rather from mussels which 
 grow in impure waters, and that the injurious qualities lie in the liver rather than the 
 byssus. 
 
 In the year 1885, at Wilhelmshaven, Germany, a large number of people were taken 
 seriously ill after eating the sea mussel, Mytilus edulis, gathered from the harbor of that 
 place. Several died from the effects. The symptoms of the poisoning were of three 
 kinds, (i) a swelling in the head and abdomen, with the appearance of red spots on the 
 body; (2) diarrhea, cramps, and prostration; and (3) paralysis. 
 
 A careful study of the conditions revealed that the water from which the mussels 
 were taken was stagnant because of the inclosing breakwater, which cut off the effects 
 of the tides. Although no sewage emptied into the harbor and ships were forbidden 
 from dumping refuse into the water, the stagnated water was so impure that its effect 
 upon animal life was highly injurious. Fishes that found their way in through the sluice 
 gates soon became so sluggish that they could easily be caught by hand. Eels were 
 
124 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 observed to lose almost all their vitality during the summer. Mussels from these waters, 
 when cooked and fed to rabbits, acted as a most virulent poison, killing them in from 
 two to ten minutes. If the mussels were transferred to places where currents of pure 
 water could flow over them they lost all their poisonous properties; and, on the other 
 hand, if harmless mussels were transferred from outside waters to the harbor they 
 acquired poisonous qualities in less than two weeks. 
 
 Virchow (1886) and Wolff (1886) affirm that the poison was not the result of any 
 decomposition and that the mussels had no external signs of disease. Wolff's experi- 
 ments indicate that the liver is the sole source of the poison. Inoculations from that 
 organ into rabbits and guinea pigs were fatal in every case in from two to twenty min- 
 utes, while inoculations from other parts were without effect. He believes that the 
 poison originated in the liver and was not due to the absorption of copper salts, as 
 popularly believed. 
 
 Another record of a serious case of poisoning from the eating of mussels by a party 
 of Alaskan Indians is briefly mentioned by Dall (1870) and Petroff (1884). In response 
 to a request for further details of the incident Doctor Dall wrote me the following story, 
 which is amplified somewhat from notes gleaned from the references just cited: The 
 Sitkan natives, being able to get better prices from the Hudson Bay Company, refused to 
 trade with Baranoff, the Russian director of Alaska. Baranoff therefore resorted to 
 importing, on a sailing vessel from Unalaska and Kodiak, a large number of Aleut 
 hunters with their skin canoes, to take sea otter in the islands of the Sitkan Archipelago. 
 In the year 1799 a party of about 200 camped on the shores of the strait separating 
 Baranoff from Chichagof Island, where the tides are great and at low water expose great 
 numbers of mussels. Being accustomed to eat them at home, the Aleuts gathered a 
 quantity of mussels and feasted upon them. In a few hours they were taken violently 
 ill, and 150 died within a day or two. This incident gave rise to the name Peril (in 
 Russian, Pogibshi) Strait, which name it bears to this day. Mussel poisoning in this 
 region is known to have occurred on other occasions and is supposed to be due to the 
 ptomaines developed in the Hquor of the mussels exposed to the sun. Doctor Dall was 
 informed by the Aleuts that specimens not actually out of water were always safe. 
 
 In Audot's " La Cuisinere de la Ville et de la Campagne," page 677, a paragraph is 
 devoted to the symptoms and treatment of mussel poisoning. A free translation of it 
 is as follows : 
 
 The true cause of the poisoning produced by mussels is not yet known, but it is a mistake to attribute 
 it to the presence of the small crabs which are found in their shells. The opinion more generally accepted 
 to-day is that the mussels, by attaching themselves to the bottoms of ships sheathed with copper, 
 absorb a certain quantity of verdigris, which produces the poison causing indigestion. Whether this 
 is so or not, the use of these mollusks sometimes leads to symptoms of very serious poisoning, of which 
 the more common are: A sharp pain in the region of the stomach, violent cramps, severe contractions 
 of the chest, an alternating quick and slow pulse, a redness and swelling of the face, an eruption of little 
 red spots upon the skin, cold sweats, and oftentimes convulsive movements and delirium. 
 
 When these symptoms manifest themselves it is necessary to combat them promptly by employing 
 an emetic (2 grains of emetic in a glass of tepid water taken several times at six-minute intervals), and 
 
FOOD VALUE OF SEA MUSSELS. 1 25 
 
 when a sufficiently long time has elapsed since the ingestion of the mussels, follow the emetic with a 
 purgative such as 60 grams of caster oil in a cup of light bouillon. If the symptoms continue in spite 
 of these means, give the patient some mucilaginous drink and call a doctor. 
 
 The foregoing account would probably frighten the average person from ever 
 attempting to use mussels as an article of food. Careful inspection, however, will 
 reveal the fact that the mussels which have caused serious illness came either from 
 impure waters or had been exposed to the heat of the sun so long that ptomaines had 
 time to form in the liquor within their shells. Mussels taken from pure water which 
 has free circulation have never been known to produce injurious effects when eaten. 
 A New York dealer who has been seUing mussels for years has never known of a case 
 of poisoning from them. Nevertheless, too much emphasis can not be given to the 
 fact that care must be exercised in choosing proper localities for the cultivation and 
 collection of mussels for market. They must be sold to the consumer in a perfectly 
 fresh condition or serious results will be likely to follow. 
 
 SUMMARY. CONCLUSIONS, AND RECOMMENDATIONS. 
 
 1 . The sea mussel, Mytihis edulis Linnaeus, is not utilized as a food to any extent in 
 the United Slates outside of the vicinity of New York City. 
 
 2. As a food material it is superior to many articles which are commonly eaten. 
 Scores of persons have pronounced it to be equal in flavor, or even superior, to the oyster; 
 it is easily digested, has high nutritive value, and is exceedingly abundant and general 
 in its range. Especially for persons living on the coast it is an excellent cheap food. 
 
 3. Along most of our eastern coast the mussel is in season for food purposes when 
 the oyster is out of season. 
 
 4. The mussel is well adapted to preservation. When canned or pickled it will 
 retain its natural flavor for months. 
 
 5. The mussel breeds at a prolific rate, it develops rapidly, requires less special 
 conditions for growth than the oyster, and may therefore be easily cultivated. 
 
 6. The only difficulty in the marketing of mussels for food purposes is that they 
 spoil quickly after being removed from the water. It is necessary to use them within 
 twenty-four hours after they are collected or ptomaine poisoning may result. To insure 
 one's self against illness from eating them, the mussels must be taken from water that 
 is pure and subject to the constant circulation of tidal currents. 
 
 7. Other important ways for utilizing mussels are as bait for the fisheries and as 
 fertilizer for soil on which onions and carrots are to be raised. 
 
 In view of these facts it is clear that the mussel beds of our eastern and western 
 coasts constitute a valuable food resource of the nation which so far has not been devel- 
 oped. The natural beds alone are capable of supplying wholesome food to thousands 
 of persons at the expense of a little trouble to collect the mussels and to hundreds of 
 thousands more people, through the markets, at a moderate price. It is possible to 
 develop an industry in the marketing of mussels which may surpass even that of the 
 oyster and at the same time have no injurious effect upon the oyster trade. The success 
 
126 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 with which mussels may be canned and pickled promises a good future for such a branch 
 of the business. 
 
 The author recommends (i) that the facts set forth in this paper be made known 
 to the packers of marine food products and widely advertised among the fishing popu- 
 lation of our northern Atlantic and Pacific coasts; (2) that investigations be instituted 
 to determine a method for preserving mussels in a fresh living condition long enough to 
 permit their being readily shipped and sold at the inland markets, and the further investi- 
 gations on methods for preserving mussels by canning, pickling, etc., which will make 
 it possible to transport to long distances without being broken or otherwise injured 
 should be continued; and (3) that a detailed study of the life history of the mussel be 
 made as of the oyster. The solution of these problems, it is believed, will help to develop 
 a new and profitable branch of fisheries industry. 
 
 LITERATURE. 
 
 Allen, E. J., and Todd, R. A. 
 
 1902. The fauna of the Exe estuary. Journal Marine Biological Association, vol. 6, no. 3, p. 295- 
 
 343- 
 Anderssen, Joakim. 
 
 1880. The fishery exhibition in Philadelphia in 1876. Report U. S. Commissioner of Fish and 
 Fisheries for 1878, p. 47-71. 
 Atwater, W. O. 
 
 1 89 1. The chemical composition and nutritive values of food fishes and aquatic invertebrates. 
 Report U. S. Commissioner of Fish and Fisheries for 1888, p. 679-868. 
 Atwater, W. O., and Bryant, A. P. 
 
 1906. The chemical composition of American food materials. (Corrected Apr. 14, 1906.) Bulle- 
 tin No. 28, U. S. Dept. of Agriculture. 
 Bertram, J. E. 
 
 1869. The harvest of the sea, 2d ed., p. 40-417. London. 
 Calkins, Gary N. 
 
 1902 Marine Protozoa from Woods Hole, Mass. Bulletin U. S. Fish Commission, vol. xxi, 1901, 
 p. 415-468. 
 COSTE, M. 
 
 1883. Report on the oyster and mussel industries of France and Italy. Report U. S. Fish Com- 
 mission for 1880, p. 825-883. 
 Dall, William H. 
 
 1870. Alaska and its resources. Boston. 
 Fraiche, Felix. 
 
 1883. A practical guide to oyster culture, and the methods of rearing and multiplying edible 
 marine animals. Pt. v. — Cultivation of mussels. Report U. S. Commissioner of Fish 
 and Fisheries for 1880, p. 810-818. 
 Fullarton, J. H. 
 
 1 89 1. On buchot mussel culture and the buchot experiment at St. Andrews. Ninth Annual 
 Report of Fishery Board for Scotland, pt. in, for year 1890, p. 212-221. Edinburgh. 
 Fullarton, J. H., and Scott, T. 
 
 1889. Mussel farming at Montrose. Seventh Annual Report of Fishery Board for Scotland, 
 p. 327-341. Pl- VH. 
 Ganong, W. F. 
 
 1889. The economic moUuska of Acadia. Reprinted from Bulletin no. viii. Natural History 
 Society of New Brunswick. St. John, N. B. 
 
FOOD VALUE OP SEA MUSSELS. 1 27 
 
 GooDE, G. Brown. 
 
 1884. The fisheries and fishery industries of the United States. Sec. i, Natural history of aquatic 
 
 animals, 709 p. — U. S. Fish Commission, Washington. 
 1887. The fisheries and fishery industries of the United States. Sec. v, vol. 11, History and 
 methods. Mussel fishery, p. 615-622. U. S. Fish Commission, Washington. 
 Gould, A. A. 
 
 1870. Report on the invertebrata of Massachusetts, 2d ed., edited by W. G. Binney. viii4-524 p., 
 12 pi. Boston. 
 H.^RDiNG, Charles W. 
 
 1883. The utilization of localities in Norfolk and Suffolk suitable for the cultivation of mussels 
 
 and other shellfish. Bulletin U. S. Fish Commission, vol. 11, 1882, p. 83-88. 
 Herdman, W. a. 
 
 1894. Report upon the methods of oyster and mussel culture in use on the west coast of France. 
 Report for 1893 of the Lancashire Sea-Fisheries Laboratory, p. 41-80, pi. i-iii. 
 King, William. 
 
 1 89 1. Mussels and mussel culture. Northumberland Sea Fisheries Committee, p. 1-8. New- 
 castle-on-Tyne. 
 Leeour, Marie V. 
 
 1907. The mussel beds of Northumberland Sea Fisheries Committee. Report on the Scientific 
 Investigations for the year 1906, p. 28-46. Newcastle-on-Tyne. 
 M'Intosh, W. C. 
 
 1885. Notes from the St. Andrews Marine Laboratory (under the Fishery Board for Scotland). 
 
 L On the British species of Cyanea and the reproduction of Mytilus edulis Linn. Annals 
 and Magazine of Natural History, vol. xv, p. 148-152. 
 MiLNER, R. D. 
 
 1903. The cost of food as related to its nutritive value. Reprint from Yearbook of U. S. Dept 
 of Agriculture for 1902, p. 387-406. 
 Moore, H. F. 
 
 1907. Survey of oyster bottoms in Matagorda Bay, Texas. Bureau of Fisheries Document No. 610. 
 86 p., 13 pi., I chart. 
 Peck, J. L 
 
 1894. On the food of the menhaden. Bulletin U. S. Fish Commission, vol. xiii, 1893, p. 113-126, 
 
 pi. 1-8. 
 1896. The sources of marine food. Ibid., vol. xv, 1895, p. 351-368, pi. 64-71. 
 Petroff, Ivan. 
 
 1884. Report on the population, industries, and resources of Alaska. House of Representatives, 
 
 Miscellaneous Document for 2d sess. of 47th Congress, 1882-83, vol. xiii, no. 42, pt. 8. 
 
 QUATREFAGES, A. DE. 
 
 1854. Souvenirs d'un Naturaliste. Paris. 
 Scott, A. 
 
 1901. Note on the spawning of the mussel. Ninth Report of the Lancashire Sea Fisheries Labora- 
 tory for 1900, p. 36-39. Liverpool. 
 Shackell, L. F. 
 
 1909. An improved method of desiccation with some applications to biological problems. Journal 
 of Physiology, vol. xxiv, no. iii, p. 325-340. 
 SiMMONDS, p. L. 
 
 1879. Commercial products of the sea. viii-l-484 p., illus. New York. 
 Verrill, a. E., and Smith, S. I. 
 
 1873. Report upon the invertebrate animals of Vineyard Sound and the adjacent waters, with 
 an account of the physical characters of the region. Report of U. S. Fish Commission 
 for 1871-72, p. 295-778, pi. i-xxxviii. 
 
128 BULLETIN OF THE BUREAU OF FISHERIES. 
 
 ViRCHOW, RuD., and Lohmeyer, Carl; Schulze, Fr. Eilk., and Martens, E. v. 
 
 1885. Beitrage zur Kenntnis der giftigen Miesmuscheln. Archiv fiir pathologische Anatomie und 
 Physiologic und fiir klinische Medicin, bd. 104, p. 161-180. 
 WoLKF, Max. 
 
 1885. Die Localisation des Giftcs in den Miesmuscheln. Archiv fiir pathologische Anatomie und 
 
 Physiologic und fiir klinische Medicin, bd. 103, p. 187-203. 
 1885. Die Ausdehnung des Gebietes der giftigen Miesmuscheln und der sonstigen Seethiere in 
 Wilhelmshaven. Ibid., bd. 104, p. 180-202. 
 Williamson, H. Charles. 
 
 1907. The spawning, growth, and movement of the mussel {Mytilus edulis Linn.), horse mussel 
 {Modiolus modiolus Linn.), and the spoutfish {Solen siliqua Linn.). Twenty-fifth Annual 
 Report of Fishery Board for Scotland for 1906, pt. iii, p. 221-254, pi. xvi. 
 Wilson, John. 
 
 1887. On the development of the common mussel {Mytilus edulis Linn.). Fifth Annual Report 
 of Fishery Board for Scotland for 1886, p. 247-256, pi. 12-14. 
 Wolle, Francis. 
 
 1894. Diatomaceae of North America, xiii-f 15+47 P-. 112 pi. Bethlehem, Pa. 
 
Bull. U. S. B. F., 1909. 
 
 Plate XIX. 
 
 '. / 
 
 ft. ■■,;• . 
 
 . '■ " :. 
 
 i . ■ 
 
 * 
 
 ■ 'k ■ 
 
 ». 
 
 ■A- 
 
 GC 
 
 PR AR Mth U 
 
 PM PAd GAM By\FrV LP A Ad 
 
 3 
 PAd GP L LP AAd 
 
 I —Interior surface view of the mantle of a male mussel. X lo. 
 
 2.-Interior surface view of the mantle of a female mussel. X lo. ci-i,*i ^.,ia,-o-^H 
 
 ■? —Lateral view of a mussel with the shell and mantle of one side removed Slightly enlarged. 
 
 4 -Lateral view of a female mussel with the shell and mantle of one side and the foot, gills, 
 and abdomen removed to show the main canals of the genital system. Slightly eniargea 
 
 Abbreviations: A, abdomen; AAd, anterior adductor muscle; A R, anterior retractor muscle; 
 By, byssus; F, follicle containing male genital products; Ft, foot; G, gills; GC, genital 
 canals; GP, genital papilla; L, liver or digestive gland; LP, labial palps; M, mantle; Mth, 
 mouth; O, ova remaining in the mantle after spawning (4 cc); PAd, posterior adductor 
 muscle- PM, pallial muscles; PR, posterior retractor muscles; S, shell; U, umbo. 
 
BuivL. U. vS. B. F. , 1909. 
 
 Pl^xVTE XX. 
 
 Orgauisnis constituting the food of mussels. X i, 
 
 Diatomacese (modified from WoUe). 
 
 1. Biddutphia rhombus (Ehrenberg) W. Smith. 
 
 2. Amphora proteus Gregory. 
 
 3. Tabellaria fenestrata Kiitzing. 
 
 4. Surirella ovalis var. ovata Brebisson. 
 
 5. Rhabdonema adriaticum Kiitzing. 
 
 6. Navicula didyma Ehrenberg. 
 
 7. Navicula lanceolata Kiitzing. 
 
 8. Navicula lyra Ehrenberg. 
 
 9. Rhabdonema arcuatum Kiitzing. 
 
 10. Navicula splendida var. puella Ad. Schmitz. 
 
 11. Biddulphia favus (Ehrenberg) H. V. H. 
 
 12. Actinoptychus undulatus Ehrenberg. 
 
Bull. U. S. B. F., 1909. 
 
 Plate XXI. 
 
 Organisms constituting the food of mussels 
 
 Diatomaceie (modified from Wolle). 
 
 13. Nitzschia sigma var. sigmatella Grunow. 
 
 14. Melosira sculpta Kiitzing. 
 
 15. Nitzschia sigma Grunow. 
 
 16. Grammatophora marina Kiitzing. 
 
 17. Rhizoselenia setigera Brighter. X 38. 
 
 18. Pleurosigma balticum W. vSmith. 
 
 19. Pleurosigma elongatum \V. Smith. 
 
 20. Pleurosigma decorum W. vSmith. 
 
 21. vStephanopyxis appendiculata Ehrenberg. 
 
 22. Synedra gallionii Ehrenberg. 
 
 23. Hyalodiscus snbtilis Bailey. 
 
 24. Pleurosigma angulatum W. Smith. 
 
 25. Coscinodiscus excentricus Ehrenberg. 
 
Bull. U. S. B. F., 1909. 
 
 Plate XXII. 
 
 Organisms constituting the food of mussels. Protozoa. (All figures except 7 after Calkins.) 
 
 1. Exuvisella marina Cienkowsky. X 780. 
 
 2. Glenodinium compressa Calkins. X 822. 
 
 3. Ceratium fusus Ehrenberg. X 315, 
 
 4. Distephanus speculum Stohr. X 960. 
 
 5. Exuvialla lima Ehrenberg. X 780. 
 
 6. Peridinium divergens Ehrenberg. X 636. 
 
 7. Prorocentrum micans Ehrenberg. X 375- 
 
 8. Tintinnopsis davidoffi Daday. X 354. 
 
 9. Tintinnopsis beroidca Stein. X 900- 
 
 t 
 
Bull. U. S. B. F., 1909. 
 
 Plate XXIII. 
 
 ^~oit '-. 
 
 '■■'■y 5 X 
 
 
 ^ n 
 
 (tN tvv/j*t, 
 
 i^ar a 
 
 ^m 
 
 
 M'® 
 
 
 
 
 
 ^ ^^2'^^ 
 
 
 y? rt a d I' 
 
 
 
 ~rQJj^ 
 
 ? iiji 
 
 ^A^^r_,. 
 
 H :^<6 
 
 
 ^. t-.C t-T 
 
 
 ^ ?J.ti oj ^ 
 
 
 ^ ■;■> ^>,_ 
 
 
 oi P rtTJ 
 
 
 ^1^1 
 
 
 
 
 
 
 ^t^^^; 
 
 
 •g-c-og 
 
 
 .s S.5:c 
 
 
 •S2i3'= 
 
 
 
 
 ■Ccna M 
 
 
 S " 5 b« 
 3 « 5 t: 
 
 
 "^icSg 
 
 
 II t"^ 
 
 
 
 "^."TOiti 
 
 'Pli 
 
 r.«ii« 
 
 
 
 '\L 
 
 -£l^l 
 
 ^ 
 
 ^kI^ 
 
 ^^m 
 
 ■^.-^i^ 
 
 OT 
 
 ISII 
 
 >T> 
 
 «t^:^-< 
 
 isi 
 
 
 coco 
 
 .£.§.2.2 
 o o o o 
 
 Oj u 11 U 
 
 C o o o 
 
Buix. IT. S. B. F., 1909. 
 
 Platk XXIV 
 
 ^ A^^^T ^^,'ZL-S "'^»Wak. 
 
 . — A imissel Ijed at Menemsha Pond, Marthas Vineyard, Massachusetts, exposet] at low tide. 
 (Photographed by Dr. K. W. Miner.) 
 
 2.— Dredging for mussels. This vessel operates on the ocean and liavsfroni Princes Bay to Fire Island, and 
 gathers from 200 to 250 bushels a day. ( Photograph by courtesy of Mr. George A. Carman.) 
 
Bull. U. S. B. F., 1909. 
 
 Platr XXV 
 
 
 !•— A heap of imissel shells, the result of a few days' work. (Photograpli liy courtesy of Mr. Ceorg 
 
 A. Carman.) 
 
 . — A heap of shells from mus,sels which have been pickled for the New York market. The shells ar 
 used as cultch for seed oysters. (Photograph by courtesy of Mr. Cieorge A. Carman.) 
 

I