I SB 618 L8 .n3 Copy 1 UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 405 Joint Contribution from the Bureau of Plant Industry. WM. A. TAYLOR, Chief, and the Bureau of Animal Industry, A. D. MELVIN, Chief Washington, D. C. PROFESSIONAL PAPER December 5, 1916 LUPINES AS POISONOUS PLANTS By C. D. MARSH and A. B. CLAWSON, Physiologists, Drug-Plant and Poisonous-Plant Investigations, Bureau of Plant Industry, and HADLEIGH MARSH, Veterinary Inspector, Bureau of Animal Industry CONTENTS Part I.— Introduction . . . Part II.— Experimental Work Pago 1 Page Part ni.— Discussion and General Con- clnsiona Literature Cited WASHINGTON GOVERNMENT PRINTING OFFICE i9ie Monograph D. Of D. DEC £3 me Washington, D. C. PROFESSIONAL PAPER December 5, 1916 LUPINES AS POISONOUS PLANTS. By C. D^Marsh aiul A. B. Clawson, Phijaiologisls, Drmj-Planl and Poisonous-Plant Investigations, Bureau of Plant Industry, and Hadleigh Marsh, Veterinary In- spector, Bureau of Animal Industry. Part I.— Introduction Summary of knowledge of lupines as poisonous plants Distribution of lupines Common names of lupines Alkaloids of lupines Ictrogen Part 11.— Experimental work Pharmacological investigations by Soll- mann Field experiments with lupines Laboratory experiments with extracts of lupine seed upon mice Part III.— Discussion and general con- clusions Failure to poison sheep in 1910, 1911, and 1912 Lupine not a cumulative poison Page- Part III.— Discussion, etc.— Continued. Toxicity of dillerent siwcies of lupine 30 Toxicity of lupine leaves for sheep 30 Toxicity of lupine seed for sheep 31 Toxicity of lupine pods for sheep 32 Toxicity of lupine fruit for sheep 32 Symptoms 33 Pathology 36 Comparison of " lupinosis " and poisoning of sheep by American lupines 36 Remedies 38 Range conditions under which sheep are poisoned 39 Treatment of range animals to avoid poisoning 41 Summary -12 Literature cited 43 PART I.— INTRODUCTION. SUMMARY OF KNOWLEDGE OF LUPINES AS POISONOUS PLANTS. EARLY HISTORY AND LATER STUDIES. The lupines have been known from very ancient times, and are mentioned by many authors, e. g., Theophrastus, Marcus Fortius Cato Censorius, and Pliny. The last-named author (ed. 1856, pp. 49-50, 452-453)^ treats of the lupine at length, especially with reference to its use as a green manure. Several species have been used as culti- vated crops in Europe, more especially for the reclamation of sandy soils. It has been used also as a fodder crop, and the seeds ground Note.— This paper will be or special interest to the stockmen of the West. 1 Bibliographic citations in parentheses refer to " Literature cited," p. 43, 52191°— Bull. 40&-16 1 ^ i.^^^ 2 BULLETIN 405, U. S, DEPARTMENT OF AGRICULTURE. ^j^ \^ into meal have been used both for domestic animals and as food for man. In Germany the land utUized for lupine, according to the latest available statistics, is 346,753.3 hectares; on 200,000 hectares of this amount it is cultivated as a green manure. The poorer people among the Greeks and Romans and the Cynic philosophers made use of lupine meal in bread. The bitter principle was recognized not only as disagreeable, but as injurious, and the seed was especially prepared in order to get rid of this property. Among the Greeks the seeds were cooked until soft, to remove the outer skin, then placed in sacks in shallow places on the seashore to wash out the bitter prin- ciple. Afterwards the seeds were dried, ground in a hand mUl, and baked into a poor bread. Only the poorest people used this meal unmixed, but others mixed it with other kinds of meal, making a more digestible flour. (Landerer, 1852.) Because the lupines were planted in Maina and there used for food, the people in that region were known as ''Lupinophagi." Lupine meal was also used by the ancient Egyptians, and is stUl used in Andalusia, Corsica, and Pied- mont. (Cornevin, 1893, p. 314.) In modern times lupine meal, after a process of "Entbitterung," has been used to some extent as food for animals. As a medicine, lupine seeds have been used since ancient times. Pliny (ed. 1856, p. 452-453) enumerates 35 different uses. The main uses, however, seem to have been as a cathartic and as a vermi- fuge. For the latter it was used as an external application as well as internally. BeUini (1876) reports in detail cases of poisoning in man from using a decoction of lupine as an enema. He states that Averrhocs and Hofman pointed out the poisonous properties of the plants, and that Paullus, 1708, reports a case of poisoning of a boy by an enema. The reference to Averrhoes and Hofman could not be verified, as apparently they only mentioned the plants as a vermifuge. The symptoms mentioned by Bellini are dyspnoea, defective sight, dilated pupils, and stupor. These symptoms, as will be seen later, compare fairly well with those of poisoning by the lupine alkaloids. Isolated cases of poisoning by lupmes were noted as early as 1860, but it was in 1872 and the foUowmg years that heavy losses of sheep occurred in northern Germany. Wliile there is evidence that some animals are poisoned by the alkaloids, most of the cases, and prac- tically all of the losses, have been from the use of lupine hay and are caused, as will be seen later, by ictrogen. The occasional poisonmg of cattle and horses reported in Europe appears to have been from the use of the seed and is alkaloidal poisoning. Sheep are also poisoned in this way, but the great losses which have stimulated the extensive investigation of the subject have been by ictrogenic poison- ing of sheep. LUPINES AS POISONOUS PLANTS. 3 In America tlie first published report of losses of sheep is l)y Chesnut (1899, p. 404-405), and this report with the papers of Wilcox (1899), Chesnut and Wilcox (1901, p. 100-110), and Slade (1903), comprise all that has been pubhslied up to the present time. Other authors have mentioned the subject, but their material is all taken from tlie reports of Wilcox, and Cliesnut and Wilcox. The first general account of lupuio poisoning in America is by Wilcox (1899). A much more extended account is given by Chesnut and Wilcox (1901, p. 100-110), with details of cases and symptoms. Wilcox notes that mature plants are the more poison- ous, and Chesnut and Wilcox definitely state that the toxic principle is mainly in the pods and seeds and that lupine hay should be cut after the seeds are shed. Both WUcox, and Chesnut and Wilcox apparently consider the poisoning of sheep in America as similar to the disease called "lupinosis" in Germany, although Chesnut and Wilcox (1901, p. 109) state that the ''chronic form of the disease" has not been recognized in America. Sollmann, hi an impubhshed report of a laboratory study of American lupmes, a report made under the direction of the Bureau of Plant Industry, which wUl be discussed more fully later, states that he failed to find evidence of the presence of ictrogen and gives details of the symptoms produced by the alkaloidal substances extracted by him. His work was not connected with field investigations, but the results, viewed in the fight of present knowledge, clearly indicate the probability that the field cases of poisonmg by lupme in America are not cases of "lupinosis" m the sense in which the temi is used in Europe, but are the result of alkaloidal poisonmg. The field mvestigations reported in this paper establish without a doubt the fact that, so far as ob- served, all cases of poisonuig of range slieep by lupines must be con- sidered as due to the alkaloids and not to ictrogen. These field investigations are in entire harmony with tlie preliminary laboratory study by Dr. SoUmann, althougli carried on in an independent way without reference to the precedmg results obtained in the laboratory. ANIMALS POISONED BY LUPINES. Wliile the losses of domestic animals have been mainly of sheep, other animals also are poisoned — horses, cattle, goats, swine, and fallow deer — and laboratory experiments on small animals indicate that none are immune to the effects of the toxic substances. Wilcox (1899) states that in Montana a few horses have been poisoned, and Chesnut and Wilcox (1901 p. 100-110) give specific instances. Poisoning of horses on the range or in pastures is not common, but is known to occur. Dammann (1902) states that cattle are affected by the alkaloid, and cases of the poisoning of cattle on the range have been reported in America, although the cases are not very weU authenticated. 4 BULLETIN 405, U. S. DEPAKTMENT OF AGRICULTURE. LOSSES FROM LUPINES. The losses from "lupinosis" in Europe have in some years been very great. In 1880, in Pomerania the loss of sheep was 5.89 per cent (Comevm, 1893, p. 316). It is stated that in some herds in northern Germany the loss was as great as one-half to three-fourths of the total number. The known losses in America are very heavy. Chesnut and Wilcox (1901, p. 106) teU of one case, among others, in which out of 2,000 sheep trailed over a region covered with a large quantity of lupine 1,000 were sick and 700 died. In another case 1,150 died out of 2,500 (p. 104). Losses of several hundred are not at all uncommon, and occasionally the deaths may be nearly 50 per cent of the whole number. More complete knowledge of the losses has been obtained in Montana than in any other State, because Montana has been under close observation for many years, and it is very possible that this State suffers more than others, but more or less similar conditions are found in other western States m which the mountain regions are used for sheep grazing. It is probable that the lupines rank as a close second to Zygadenus in causing losses of sheep. DISTRIBUTION OF LUPINES. While lupines are found m the eastern United States rather spar- ingly, and are there represented by only three species, in the Western States there is a large number of species, and these frequently grow in large masses, so that sometimes they are cut for hay. They form an important factor in the number of forage plants. Horses seem to be especially fond of them and wiU sometimes eat the green plants with great greediness. Of the species of lupines in America, only a few have been used in this investigation. One of these, Lupinus sericeus, is illustrated in figure 1. A thorough systematic study of the genus is in progress by the Bureau of Plant Industry, and further work is being prose- cuted for future publication, dealing with the characteristics of the different species from the standpoint of chemistry and pharmacology, as well as from the standpoint of field experimentation. COMMON NAMES OF LUPINES. The lupines are known under a large number of common names. Among these are sundial, old-maid's bonnets, Quaker's bonnets, Indian beans, wild beans, blue pea, and blue bean. In some sections the name loco is used, but this is generally by those who do not know the true locoes. LUPINES AS POISONOUS PLANTS. 5 ALKALOIDS OF LUPINES. No investigations of the alkaloids of iVinerican lupines have been published, but the European lupines have been the subject of ex- FiG. 1.— Lupine (Lupinus sericeits). tended study, and the literature, especially of the chemistry of the alkaloids, is very large. Cassola (1834) attempted to isolate the alkaloid of Lupinus alhus, but probably did not obtain the pure alkaloid. Landerer (1852) 6 BtTLLETTlSr 405, U. S. DEPARTMENT OF AGRTCTTLTtTKE. obtained a substance that showed a begmnmg of crystallization, which he called lupmin. Beyer (1871), found an alkaloid in lupine from a study of Lujnnus luteus. Baumert issued a series of papers from 1881 to 1889. Baumert (1886) summarizes the knowledge to date and announces definitely the presence of two alkaloids in Lujnnus luteus, lupmin (C21H40N2O2), and lupinidin (CgHigN). Schmidt (1897), Davis (1897), Callsen (1899), Schmidt (1904), and Bergh (1904) summarize and bring the subject to date with extensive additions to the detailed chemistry of the alkaloids. Schmidt (1897) states the alkaloids as lupinm (C21H40N2O2), lupmin (CgH^jN), ''dextro- rotatory-lupanm " (C15H24N2O); and inactive lupanin (CgoH^gN^O,) . These are found in the lupines examined, as follows: Lupinus angustifolius dextrorotatory-lupanin. Lupinusalbus rdextrorotatory-lupanin. Unactive lupanin. Lupinus luteus {IT^!"^; Uupinidm. Lupinus niger flupinin. Uupinidin. Lupinus perennis dextrorotatory-lupanin. Lupinidin is identical with spartein C15H26N2 (Muenk, 1914, p. 394). CaUsen (1899) gives an extended account of the chemistry of the alkaloids of Lupinus angustifolius and L. perennis. Willstatter and Fourneau (1902) give experimental evidence that the formula of lupinin is C10H19ON. Schmidt (1904) and Bergh (1904) in extended papers discuss further the alkaloids and state that another alkaloid is found in Lupinus perennis, oxylupanin (C15H24N2O2). Liebscher (1880), Lowenthal (1888), and Eaimondi (1891) give details of the pharmacology of the lupine alkaloids. The action of all is practically the same but differs quantitatively. Liebscher states tliat lupinidin is 10 times as active as lupinin. There is a direct paralysis of the medulla and cord, the respiratory center being first paralyzed, and then the vasomotor. This is accompanied by weakening of the heart. There is a fall in blood pressure, a slowing of the pulse, and dilation of the pupils. Death is produced by asphyxia, with which are associated convulsions. There is no cm-are action. The dose required to produce any symptoms is ordinarily fatal. The alkaloids are less poisonous for mammals than for cold-blooded animals. Small repeated doses pro- duce no effect, nor do they estabhsb a condition of tolerance. ICTROGEN. Early in the investigation of the poisoning of domestic animals in northern Europe by lupines, causing the disease which came to be known as "lupinosis," it was observed that these were not cases of poisoning by the recognized alkaloids of the lupines. Lupinosis has LUPINES AS POISONOUS PLANTS. 7 a definite line of symptoms distinctly different from those produced by the alkaloids, especially characteristic being a hepatitis, which pro- duces a jaundice exhibited in the conjunctiva and visible mucous membranes of the Uving animal. Kiibn (1880), Roloff, (1883), Arnold and Lemke (1881), as well as others, found that the intoxica- tion known as lupinosis could not be produced by alcoholic extracts, but was produced by the marc of the seeds; if the poisoning were alkaloidal, tlie reverse would be the case. Dammann (1902, p. 343) states that the plant often becomes more toxic on keeping. More- over, while the alkaloids are always present the ingredient producing lupinosis is inconstant. The plants raised on some fields always produce poisoning, wliile on others they are harndess (Raimondi, 1891). It was. found (Dammann, 1902, p. 342) that the substance producing the disease is insoluble in alcohol, ether, glycerine, and fatty oils, and is soluble with difficulty in water. It is not readily destroyed by dry heat, but steam under pressure makes it harmless. This h\T)othetical substance was called ictrogen by Kiihn (1880) and lupinotoxin by Arnold and Schneidemiihl (1883). It has only been recognized by its physiological action. Ictrogen is not considered to be a product of the metabolism of the lupine, but to be the result of the growth of microorganisms upon the plants. Tliis explanation is not based, however, upon any experi- mental evidence, but is reached by a process of eUmination of other possible theories. This is the theory advanced by Dammann (1902, p. 341-343). Other theories of the cause of lupinosis have been advanced. For example, Ziirn (1879) propounded a theory that the disease is produced by microorganisms in or on the lupine leaves; in other words, that lupines do not cause the disease, but simply serve as a carrier. This theory has not been taken very seriously by others, while the theory that the disease is produced by ictrogen and that this substance is produced through tlie action of some unknown micro- organisms upon the lupines is quite generiilly accepted as the most probal)lo explanation. PART II.— EXPERIMENTAL WORK. PHARMACOLOGICAL INVESTIGATION BY SOLLMANN. SCOPE OF THE WORK. A series of experiments upon Montana lupines, identified as Lupinus sericeus, L. leucopJiyllus, and L. cyaneus, was conducted by Dr. Torald Sollmann, under the general direction of V. K. Chesnut, then in charge of the work on poisonous plants in the United States Department of Agriculture, and following is a report of the results. Eighteen animals, rabbits and guinea pigs, were fed upon pods and seeds \\Hth no results, none of them eating enough to produce toxic effects. 8 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTUEE. Extractions were made of the seeds and pods, and impure alkaloids were obtained. The experience in this work leads to the suggestion of the following method of extraction: Moisten the powdered drug with alcohol containing 1 per cent of HCl; pack in percolator; macerate with alcohol; percolate with alcohol until the percolate gives only small turbidity with Mayer's reagent. Mix the percolate with sand and evaporate the alcohol. Treat the residue repeatedly with warm water, until it gives off only a slight reaction with Mayer's reagent. To the united filtrate add Mayer's reagent to complete precipitation. Wash the precipitate, suspend it in a little water, and decom- pose with HjS; filter. Evaporate the filtrate to a small voliune, add an excess of Ca(0H)2, filter, exhaust the precipitate and filtrate separately with ether, as quickly as possible, neglecting the last traces. Evaporate the ether. Treat the residue with absolute alcohol acidu- lated with H2SO4. Let stand 24 hours. The precipitate will contain the lupinidin, the filtrate the other lupine alkaloids. These will require further purification. CHARACTERS OF THE ALKALOmS. Physical characters. — The physical effects of the aklaloids make it likely that they are similar to those occurring in the European species. Several of these characters were observed in the course of the isolation of the alkaloids. The (impure) alkaloids were obtained as brown oily liquids of a strongly alkaline reaction and a strongly bitter taste. They were easily soluble in water and in alkalies. They were slightly soluble in petroleum ether. No crystals were obtained. During their sepa- ration a strong odor resembling conin, characteristic of lupinidin, was perceptible, especially when strong soda was added. The isolated alkaloids were almost odorless, but again developed the odor very strongly when 10 per cent soda was added. Chemical characters. — Strongly heated, they boiled and evolved dense, white fumes. Strong sulphuric acid, cold or heated, alone or with formaldehyde or bichromate, gave only browning. Strong nitric acid also gave no characteristic reactions. Precipitation reactions. — -The alcoholic solution gave partial pre- cipitation with sulphuric acid. The dilute neutral aqueous solutions of the chlorid or sulphate behaved as follows : NaOH (1 per cent): Slight precipitate. NaOH (strong): Precipitate, partly soluble n excess of the soda. (NH4)0H: No precipitate. NaaCOj: No precipitate. Mercuric chlorid: Amorphous precipitate, easily soluble in excess of HCl. The precipitate was incomplete, giving further precipitate with Mayer's reagent, and also the lupinidin test with alcoholic sulphuric acid. Picric acid: Fair amorphous precipitate. Tannin: Precipitate, soluble in excess. lodin in KI : Good amorphous precipitate. Pot. f errocyanid : No precipitate. Pot. bichromate: No precipitate. LUPINES AS POISONOUS PLANTS. 9 Nature of the alkaloids. — The alkaloids were not obtained sufficiently pure to make definite characterizations possible. Their close agree- ment with those obtained from the European species in physiological action and fatal dose make it very probable that they are closely related, if not identical. Lupinidin was fairly well identified by the conin odor, by the insolubility of the double clilorid formed y\\ih. mer- cury, and by the insolubility of the acid sulphate in absolute alcohol. The precipitation by these reagents was not complete, so that there must be other alkaloids present, presumal)ly lupinin and lupanin. This portion of the work needs further elaboration. The yield of crude alkaloids in the extraction was as follows: Specimen IV: Lupinus sericeiui, parasitized pods, 0.02 per cent from alkaline ex- tract; 0.133 per cent from watery extract. Specimen V: Lupinus cyaneus, seed, 2.462 per cent. Gerhard found from 0.5 to 1.2 per cent in the European lupines. TOXICITY OF THE EXTRACTS. The various extracts, prepared as described, were admmistered to rabbits and guinea pigs, by mouth, stomach tube, and hypodermi- cally. The symptoms were practically identical, and will be described later. It was found : (a) That the toxic principles must be alkaloidal rather than ictrogenic. (6) That the fatal dose of the drug (as extracts) to ral)l)its by stomach, in the case of the seeds of Lupinus sericeus and L. leucophyllus, vva-s between 30 and 50 grams per kilogram, with the seeds of L. cyaneus between 70 and 100 grams per kilogram, and with empty pods of L. seria'us and L. cyaneus over 100 grams per kilogram. (c) That the fatal dose of the crude alkaloids (in the purest lomi in which they were used, from Specimen V) lies, for rabbits, gastric administration, between 1.2 and 2.4 grams per kilogram; for rabbits, hypodeniiic admirdstration, between 0.123 antl 0.246 grams per kilogram (agrees with Lowenthal's (1888) figures for lupinitlin and lupanin, viz, 0.2 and 0.4); for guinea pigs, hypodermic administration, between 0.052 and 0.1 gram per kilogram. {d) That the alkaloids are five to ten times as toxic for rabbits when given hypo- dermically as when given by the stomach tube. (c) That guinea pigs are about twice as susceptible to the poison, when given liypo- dermically, as rabbits are. (/) That repeated administration of the poison to animals did not increase their 8U.sceptibility, as is shown by the fact that rather prolonged feeding was not fatal, and that no tolerance is produced in this manner, as is shown by rabbits 77 and 78 A. The animals in either case, after having been injected repeatedly, died from the last dose, although these doses were not very greatly above the fatal limit. SYMPTOMS OF LUPINE POISOMNG. It will be iisefid to describe the typical course, which occurs with only minor variations when any of the extracts are administered. The symptoms set in with a general depression. The animal is very quiet, sits flat with ears laid back; the respiration is rapid, labored, and irregular. The temperature is not altered in a constant manner. After a time it is noted that the animal, while apathetic 52191°— Bull. 405—16 2 10 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. if left alone, is quite excitable when disturbed. The reflexes are heightened. The movements are brusque and exaggerated. The depression gradually deepens; the animal partly loses control of its hind legs, so that these tend to drag. Often the animal Hes on its belly, the head on the floor and legs spread out. It is still able to walk. It soon loses this ability and sits or lies stiU. When disturbed, it reacts with shivering, and becomes more and more convulsive. Stimulation now produces more or less violent spasms, the first spasm being strongly tetanic. The animal may assume the strychnin posi- tion, with legs stretched out, and back arched in; or it may rise on its feet, the back arched upward. The spasm soon becomes clonic and incoordinated, the animal pawing the air in an aimless manner. This is followed by relaxation, and the animal remains quiet unless disturbed, which disturbance would cause another spasm. After a time the convulsions occur spontaneously. In milder cases there may be no general convulsions, but twitching of isolated muscles— of the face, ears, neck, back, and extremities. The head may swing in a rhythmical pendulum movement. The respiration during this convulsive paralytic condition is slow, shallow, and irregular. The pupils are variable, but need not be dilated (which speaks against the view that they are asphyxial; the mucous membranes are also a bright pink). Many animals urinate copiously. The animals may remain on the abdomen or recover a sitting postute for some time after the onset of the convulsions, but after a time they fall on the side. The respiration becomes gasping. Asphyxial convulsions set n, and the respiration stops from half a minute to 1 minute before the heart. The depressant and convulsive symptoms agree with those de- scribed by Lowenthal (1888), Gemma (1882), and Raimondi (1891) for European lupine alkaloids. It is not possible to make any general statement as to the time required for the development of the different symptoms, since this is extremely variable. It is remarkable, however, that a consider- able time may elapse before any pronounced symptoms appear, and this even when the solutions are administered under the skin. It is to be noted that doses which are little below fatal produce only very slight symptoms. Recovery may occur from any stage and is usually so complete that the animal gains on its original weight. The intoxication leaves no post-mortem lesions, gross or microscopical. OPERATIVE EXPERIMENTS WITH LUPINE ALKALOIDS. The effects on blood pressure, respiration, etc., were studied on five dogs, anaesthetized with morphin and ether, and arranged for tracings. The alkaloidal extract of Specimen V (seeds of Lujnnus LUPINES AS POISONOUS PLANTS, 11 cyaneus) was injected into the femoral vein, in progressively increas- ing doses. Tlie dose is calculated as grams of drug (not of alkaloid) per kilogram of body weight. Arranged by doses, the effects were briefly as follows : SMALL DOSES OP 0.1 TO 0.4 ORAM PER KG. Respiration : First quicker and deeper; then somewhat slowed; irregular, and shallow. Carotid blood pressure: Rise, fall, rise, normal. Heart : Rate somewhat quickened; strength somewhat diminished. TOXIC DOSE.S OF 0.5 TO 0.75 GRAM PER KG. Respiration: First quickened and deeper; then somewhat slowed, irregular, and shallow; may stop. (Carotid blood pressure: Rise, then great fall; effect of sciatic stimulation le.ssened. Heart: Rate first slowed, then quickened; when vagi were cut, slowed; strength, weakened. VERY LARGE DOSES OF 0.9 TO 6.25 GRAMS PER KG. Respiration: For a few moments deeper; then very shallow and stops. Carotid blood pressure: First slight rise, then great fall. Heart: Rate first slowed, then quickened, then stopped; strength weakened. Convulsions may occur from 1 gram up. DISCUSSION OF EFFECTS. Respiration. — The respiration shows a short stimulation (increase of rate and depth), followed by depression (slowed, irregular, shal- low); with the larger doses it stops before the heart. The action is probably on the centers, for it occurs after section of the vagi, and when stoppage has occurred it can not be revived by asphyxia, slap- ping, or stimulation of the sciatic, or injection of saline. No recovery occurs from even a just fatal dose after an hour of artificial respiration. The respiratory center is the first vital center to give out completely. Blood pressure. — This shows a short, moderate rise, followed by a more lasting fall, which is quite marked with the larger doses, even those which are not fatal. ^^Uthough tlie changes often coincide with respiratory changes, the two are not interdependent, for they may occur independently, and blood pressure changes occur even during artificial respiration and are not influenced by the latter. Whether the changes were central or peripheral was not investigated directly; but, from the fact that when vasomotor paralysis exists stimulation of the sciatic is sometmies efl'ective and sometimes ineffective when asphyxia is efl'ective, it is rendered very probable that the action is central. The vasomotor paralysis may precede, coincide, or follow that of respiration. It may be partial or so nearly complete that the pressure smks to some 20 millimeters with a good heart action. Tlie heart rate. — With toxic doses there is first slowing, then quick- ening; with minimal and maximal doses, there is usually quickenuig only. Tlie slowing and secondary quickening occur equally well when the vagi are divided ; they are therefore at least partly periph- eral. They are not always accompanied by changes in the strength 12 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. of the heart, hence they are probably not muscular. Further, when the heart is quickened by large doses, electric stimulation of the vagus has but little effect. The drug may therefore be said first to stimulate and then depress the vagus end mechanism. It may have a similar action on the vagus center. Strength of the heart. — This is affected only by rather large doses, but it is then always depressed. Experiment 87 shows that the life may be kept up with a complete vasomotor paralysis, if the heart beats well. This tends to show that the stoppage of the heart, which forms the final cause of death, must be due to paralysis of its muscles. This is confirmed by the fact that it can not be revived by injection of normal saline. Convulsions. — Convulsions were observed in but two of the five cases. This may be due to the anaesthetic or to the difficulty of securing proper dosage. When observed, however, they preceded respiratory distress and were not connected with any change in blood pressure, so that it seems that they are produced by a direct central action. Slceletal muscle. — The existence of convulsions in the last stages, as well as the result of stimulation of peripheral and of the sciatic, show that muscle and nerve are not paralyzed. Cause of death. — The following vital functions are eventually paralyzed by the lupine: Respiratory center; vasomotor center; cardiac muscle; the last named being the last to become paralyzed and being the final cause of death. SUMMARY. The results of the investigations are in many respects incomplete and emphasize the need of a more exhaustive chemical and pharma- cological study of the American lupines. They have shown, how- ever, that these lupines contain alkaloids which are toxic or fatal if a sufficient ciuantity of the plant is consumed, but which are harmless if the consumption is below a certain limit. Up to this point the lupines may be a useful food if due precautions are observed that the limits are not surpassed. These alkaloids could also be largely removed by leaching with water. The ictrogen, which is especially feared in Europe, was not found in any of the American samples. It would be of great importance to determine whether this ictrogen is uniformly absent, for if it is not, much more stringent precautions would be necessary. CONCLUSIONS. 1. Feeding with the lupines does not produce any symptoms in rabbits and guinea pigs, as a sufficient quantity is not taken in this manner. 2. The injection of extracts, by stomach or skin, is fatal if suffi- ciently large doses are used. LUPINES AS POISONOUS PLANTS. 13 3. No ictrogen was found in any of the six specimens, 4. The toxic constituents are alkaloidal and seem to agree with those of the European species. 5. These alkaloids produce a stimulation and then a paralysis of the following structures: The respiratory and vasomotor centers, some convulsive centers, the vagus end mechanism, and perhaps the vagus center. Large doses given intravenously paralyze the heart muscle. The convulsions do not appear to be purely asphyxial. 6. Pronounced symptoms are seen only when almost fatal doses are given; smaller amounts do not produce any conspicuous effects. When death does not occur acutely, there are no late effects. Re- peated administration has no influence on the action. 7. The cause of death is paralysis of respiration. Death occurs, with hypodermic administration, in 12 minutes to 2.^ hours; when given by stomach, in 10 minutes to 3^ hours. The symptoms set in only shortly before deatli. 8. The fatal doses for rabbits by the stomach, figured for the original drugs, are as follows: For .the seed of Lupinus sericeus and L. leucophjllm, between 30 and 50 grams per kg.; for the seed of L. cyaneus, between 70 and 100 grams per kg.; for the hulls of L. cya- neus, and L. sericeus, over 100 grams per kg. 9. The fatal dose of the crude alkaloid for rabbits, gastric admin- istration, lies between 1.2 and 2.4 grams per kg.; for rabbits, hypo- dermic administration, between 0.123 and 0.246 gram per kg.; for guinea pigs, hypodermic administration, between 0.062 and 0.1 gram per kg.; for dogs, intravenous administration, about 0.012 gram per kg. 10. The fatal dose for rabbits is between 5 and 10 times as large when the alkaloids are given by the stomach as when given intrave- nously. Guinea pigs are more susceptible to the alkaloids than rabbits when the solutions are administered hypodermically. 11. In the treatment of the poisoning, artificial respiration was found useless. Good results were obtained with potassium perman- ganate, diuretin, and tea. FIELD EXPERIMENTS WITH LUPINES. Field experiments with domestic animals have been carried on for six years — in 1909, 1910, and 1911 at Mount Carbon, Colo., and in 1912, 1913, and 1914 at Greycliff, Mont. Two species, Lupinus cnmatus and L. myrianthus, were used at the Mount Carbon station. At Greycliff most of the work was done with two local species, i. leucopsis and L. argenteas, but two feedings were made with L. leucophyUus collected in Idaho in the Caribou National Forest. Not only were different species used, but feedings were made of different parts of the plants and also with the plants at different stages of growth. 14 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. B rH Id c^ S o-d .6-5 O^ ^|:i:S^ § S ti 1^ •g'S 6)3 I it; 3 ; ^•o = ggoH oo O.Q.P, ft 13 p2 !; c^ '-' §3 S S 8 :3 Is s?5 Oo Om §§ gs :3 :3 000 S|SSf -:2s § § 1.8 I g LUPINES AS POISONOUS PLANTS. 15 . . . * pt .5 o o 0-.0 «■> 0x000 00 tOiO U5 CO w I- »6 Jc ^ "5 CO e^ 10 ec CM o5 oc . ; cc ci gj ic c^ « 3 m o> § cS siS S3 1^1 •tf CM c S'O _o_o-i: S 'C'D'O'C'O'O'O'CO'O'D'C'CTSS SE2 o22o 01 "^ - . "- dS d^ dg- ©■O (Cia j^T! ^ I ►:?^ :< << • S C» OQ < — 0000 « ' d k. « E I !§ & fcs ^5 - ill if' C O "5 ox '- • . bjb • bi) b£ M tiic bjb'* 3 '3333 = 1 Is 11 OC' CM IC OS . X5CM -< tec t^iomioSio coiocoS uiccM-^rtOc'cocM-Jx — CM! s? lii 3s 0000 8iS2 S2S S2: o o i^ « -i< ■« « SS«SSS3Sf:SSSS-5S SS 525 55 5 5S 52 ff-g SS S §^ ^S ST* S^"^ p^ ;:;:;:: :'^ ; : : : : :'~' S: ::::::: o : : : : ; : o > > .-; "til '.'.'.'.'.'.'.'. ti:i S '.','. '. ', \ bc 2?5S2D.;i«g|^f Sugars SSS^ 000 o^ 00000000 OJ3-2 0000 I 8 U ;3f^?; 16 BULLETIN 405, U. S. DEPAETMENT OF AGRICULTURE. flg.9 :-sa ^51 s ■ 55 5; )— 1C<< .-KM- ^ O O O O ( fed S'S. ■O "O TJ T3 O S- O T3 ® <^ :< :-5h^h^ h^ i::.^ 0.K? i22 SBS2 222S < ^^^"^d^" - d 3 "3 3 :::.•:?•••■•••■■•■•■■■.■•'.':;:::••:::!•■ 5? w >0 Cfi — C% -(< X OC 00 OS 00 o o o o ;§ 5! I II I I llllllllllllllllllllllllllllii^^^^^ ^^Siiiiiii^iisg^iiigdidi^^ ^ 52191°— Bull. 405—16 3 18 BULLETIN 405^ U. S. DEPARTMENT OF AGRICULTURE. S o illll $5 II %4^ i is gii^sSis^ss Bl- 6 6 6 6 6 6 6 6 6 6 ^--^ • iS^S I 1 :'dSo;z; ipq^ : ;o ; .3 ,2 W) tao MM MM. -MMM.MM. imi Sg § IM CO 00-^ COOrHCOt^CO^r^iOC ^CO O 0000 l^ 0> 00 lan1. Animal. Amount used. Used per 2n prams of animal. Mouse. Weight. Extract. Plant. Extract. Plant. Lupinus leucopsis: 1914 seed No. 39. No. 40. No. 41. No. 42. No. 49. No. 49. No. 50. No. 51. No. 52. No. 53. No. 54. No. 56. No. 57. No. 58. No. 59. No. 60. Orams. 24 19 22.5 21 18.5 C.c. 0.20 .15 .20 .25 .15 .5 .26 .5 .2 .25 .15 .25 .16 .25 ■M Grams. 0.24 .18 .24 .3 .18 .6 ,3 .6 .24 .3 .18 .3 .18 .3 .18 .09 C.c. Grams. 0.25 .237 . 266 .357 .25 .8 .30 .65 .25 .3 .335 .2075 .35 .168 . 1185 Death in 12J minutes 1)0 Sick; recovery. Not sicif . 1913 seed Do Lupinus luteus Do 0.2 .7 .3 .54 .21 .26 .14 None. Sick; recovery. Symptoms. Death in 3 minutes. Do 2i 23 23.5 24 27 22.5 21.5 21.5 26.75 19 Lupinus albus Do Lupinus angusti- folius. Do Death in 19 minutes. Symptoms. Death in 6J minutes. Symptoms. Lupinus leucophyl- lus: 1913 seed Do Lupinus argenteus: 1913 seed Do Do Symptoms. In regartl to mouse No. 49, it should be stated that inasmuch as the first injection of 0.15 c.c. of extract produced no results, a second in- jection of 0.5 c.c. was given shortly afterward. From the known facts in regard to lupine poisoning it is not to be presumed that there was any appreciable accumulative effect from the precedmg injection. Table 3 shows very clearly that by this method of experimentation Lupinus albus and L. angustifolius appear to be about equally toxic. L. luteus, however, is much less toxic, it being necessary to take prob- ably three or four times the quantity in order to produce results. It 28 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTURE. may be noted in passing that L. luteus is the species which is said to be responsible for the so-called ictrogenic poisoning which occurs in northern Germany. In regard to the American species, L. leucopsis and L. leucophyllus are about equally toxic and do not differ much from L. alius and L. angustifolius. L. argenteus appears to be much more toxic than the other American species examined. It should be noted that in these experiments on mice the animals died of respiratory paralysis, with marked dyspnoea, the heart some- times contmuing to beat as much as a minute after respiration had ceased. The work with extracts is of a preliminary character, and it is intended to prepare for future publication an extended study of the alkaloids and the effect of the extracts. PART III.— DISCUSSION AND GENERAL CONCLUSIONS. FAILURE TO POISON SHEEP IN 1910, 1911, AND 1912. In the early work of the field experiments it was assumed that the lupines were sufficiently toxic to poison animals in the course of ordi- nary feeding. It was thought that if the animals were confined and given little or nothing of other food material and were abundantly supplied with lupine, symptons would appear if the plants were toxic. There was little in American literature to indicate the probable dosage. Chesnut and Wilcox (1901, p. 108) state that 150 pods were fed to each of two sheep and both were fataUy poisoned. Accord- ingly, in 1910 the sheep used were confined in corrals and were fed all they would eat. One animal, sheep No. 102, between July 6 and 30, ate 128 pounds of lupine tops, including leaves, flowers, and fruit, and another, between August 25 and September 7, ate 55.5 pounds of seed-containing pods, with no iU effects other than a loss of weight. Sheep No, 105, which received the 55.5 pounds of pods and seeds, was given on some days as much as 8 pounds. The experience of 1911 was similar and with no more results. Although a large number of experiments were made in 1912, in only one case were there harmful results. This animal, sheep No. 180, was fed 0.85 pound of lupine seeds on September 15, and the next day it was found dead in the pasture. At that time, because of the large number of negative experiments, it was thought that the death of the animal must be due to some other cause than lupine poisoning. The more complete knowledge of the effect of lupine, brought out in the work of 1913 and 1914, makes it evident that this was a case of lupine poisoning. AU the other cases of 1912 were negative. In comparing the work of these years it will be noticed that in 1913 the feeding of seeds was done in a single day, and in most cases the quantity fed was eaten in a short time. This was true of sheep No. 180 in 1912, which ate the given quantity within an hour. In LUPINES AS POISONOUS PLANTS. 29 1914 the experiments were by forced feeding, so that the animal received the total quantity in a short period of time; while m 1910 and 1911 some of the animals received large quantities, but the feed- ing was distributed over a long period. Although in some cases as much as 8 pounds was fed in a single day, this was eaten in a more or less leisurely way. In 1912 two sheep, Nos. 175 and 168, were drenched with the fruit, No. 175 receiving 1.435 pomids and No. 168 4.198 pounds, and showed no symptoms, although the 1914 experiments indicated that the toxic dose of fruit is about H pomids. Sheep No. 175, however, received its luphie in three doses, between 10.30 a. m. and 3.30 p. m.; it is possible that tliis animal might have been poisoned had it re- ceived the material in a single dose, as the quantity given was close to the toxic hniit. But sheep No. 168 received 4.198 pounds, be- tween two and tlu-ee times the toxic dose as detemimed m 1914; this material was given in six doses, between 8 a. m. and 7 p. m. It seems probable that the only reason this animal was not poisoned was because of tlie lenglli of time during which the material was given. It appears to be a fan* inference that the excretory apparatus of the sheep can take care of the toxic substance of the lupuie provided the quantity given at any one time does not reach the toxic hmit. It is hoped to carry on later detailed experiments to show just how this is done — experiments for which adequate facihties have not been available thus far. It is probable, liow^evor, that this excretory work is done largely by the kidneys, since prelimmary experiments with other toxic substances upon sheep indicate that the kidneys are very efFicient in the removal of some toxic substances. It has also been shown by othei*s that the lupine alkaloids are found in the urine. The failure to get results in the earher experiments was due to the fact that the sheep did not get at any time more than the oxcretoiy apparatus could remove before the toxic limit was reached. LUPINE NOT A CUMULATIVE POISON. The lupines as poisonous plants do not have a cumulative effect. This has an important bearing on range management of sheep, for it is evident that sheep may graze contmuously on lupines with no bad results, provided the toxic limit is not reached at any one time. Inasmuch as the toxic dose is a fairly large quantity, and sheep do not ordinarily show any special fondness for the lupines, well-fed animals are not likely to be poisoned by lupmes. It is only when, for some reason, they eat an unusuall\^ large quantity that losses occur. This is discussed in more detail under "Range conditions imder which sheep are poisoned" on page 39. 30 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTURE. TOXICITY OF DIFFERENT SPECIES OF LUPINE. The field experiments give little information as to any difference in toxicity between the species of lupines. While only one of the two species used in the experiments with horses produced effects, viz, Lupinus myrianthus, the feedings of L. comatus were not conducted under exactly the same conditions, the period of feeding bemg con- siderably longer than in the experiments in which poisoning was pro- duced by L. myrianthus. The probable reasons why sheep were not poisoned on Lupinus myrianthus and L. comatus are discussed on page 28. Nearly all the experiments at Greycliff were on L. leucopsis. The field experi- ments on L. argenteus and L. leucophyUus were so few that it is not safe to make any deductions. It seems probable that in the experi- ments of feeding the seed of L. argenteus, the dosage was just a little too small, even granted that the plant is equally toxic with L. leucopsis. The experiments with mice detailed on pages 25 to 28 indicate that the European species, Lupinus alius and L. angustifolius, are about equally toxic with L. leucopsis and L. leucophyUus, while L. luteus is much less toxic, the dosage probably being at least three times as great as that for the other species. Inasmuch as the experiments on mice were few in number, too much importance must not be at- tached to the results. They are interesting, however, as giving some indication of the probable comparative toxicity of the species ex- ammed. These experiments with mice give an indication of the probable toxicity of the leaves as compared with other parts of the plants. TOXICITY OF LUPINE LEAVES FOR SHEEP. Sheep No. 243 was an undoubted case of lupine poisoning. The symptoms were typical and it received only loaves. It was impos- sible, however, to verify this by other experiments. The other ani- mals (Nos. 295, 266, 256, 290, and 306, withZ. leucopsis, and Nos. 263 and 307 with L. argenteus) were fed much more, in some cases more than tln-ee times as much, without any effect whatever. It should be added that while all animals upon the range apparently graze upon lupine with impunity, sometimes eating very large quantities, there are cases when it seems probable that lupine leaves must be toxic. For example, cases of undoubted lupine poisoning in the Absaroka National Forest, examined by Dr. Hadleigh Marsh in the summer of 1914, apparently did not have an opportunity to obtain enough of the seeds to cause the difficulty. If it could be assiuned that the leaves are sometimes toxic, these cases would be much more easily explained. Many similar cases of range poisoning have oc- curred where it was difficult to explain the loss except by assuming LUPINES AS POISOXOUS PLANTS. 31 that the lupine leaves are to.xic. Moreover, laborator}- work, con- ducted with the assistance of Mr. O. F. Black, shows clearly that there is a large quantity of the alkaloid in the loaves, although less than in the seed. A careful analysis of the cases of sheep fed with leaves offers no ex- planation for the difference in results, although many possible factors have been taken into consideration, such as difference in animals, cUffer- enco in methods of administration, seasonal change of toxicity, etc. All that can be said at this stage of the investigation is that while lupine leaves are not always injurious they are toxic, and under some condi- tions — conditions wliich can not now be defined — they cause illness and death. It is evident that no definite statement can be made as to the toxic and lethal dose of leaves for sheep. TOXICITY OF LUPINE SEED FOR SHEEP. Table 4 is a statement of the sheep poisoned by lupine seed in showing the quantity in each case which produced the result. T.\BLE 4. — Sheep poisoned by lupine seed in 1913. 913, Feed and animal. Date fed. Pounds fed per 100 pounds of animal. Result. Unground seed : No. 209 Aug. 15 Aug. 17 Aug. 15 Aug. 17 Aug. 31 Sept. 2 Sept. 6 0.561 .705 .268 ..542 .441 .245 .439 Sick: repoverv. Death. Sick: recovery. Death. Do. Sick; recovery. Do. No. 1S4 Ground seed: No. 210 No. 201 No. 1S5 No.212 No.203 Inasmuch as sheep No. 208 received 0.551 pounds of the unground seed without any toxic effect, it would appear that the dose received by sheep No. 209 (0.561 pound) with resulting illness, must have been very near the toxic limit. As the only sheep that died (sheep No. 184) received 0.705 pound, the lethal limit, so far as these experiments show, lies between 0.561 and 0.705 pound. When gi-ound seed was used, the dosage was much smaller, as would be expected. Sheep No. 212 was poisoned by 0.245 pound, and sheep No. 210 by 0.268 pound. Others were fed larger quantities without effect; for example, sheep No. 196 received 0.425 pound, and sheep No. 207, 0.423 pound, wliile several received 0.3 pound or more. Sheep No. 196, however, received its dose in 2 daj^s, whereas the others received theirs in a single day. It seems that sheep may be poisoned on as little as 0.25 pound or may receive as much as 0.423 pound without effect. 32 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. The two cases of death resulted from doses of 0.543 and 0.441 pound. The general deduction from the experiments of 1913 on ground seed was that the toxic dose was between 0.25 and 0.5 pound, and the lethal dose about 0.5 pound, with the probability tliat in the average cases the lethal dose was somewhat more, perhaps nearly 0.6 pound. It was considered that these experiments determined the dosage nearly enough for practical purposes, and in the experiments of administering ground seed in 1914, which were mainly with reference to the effect of antidotes, the dosage was intended to be heavy enough to produce serious illness, if not death. The general results showed that the estimate of dosage made in 1913 was approximately correct, and that the toxic dose is somewhat less than 0.5 pound, sometimes as low as 0.25 pound. TOXICITY OF LUPINE PODS FOR SHEEP. The number of experiments of feedmg lupine pods was not suffi- cient to determine the dosage with any exactness. Sheep No. 253 died on August 6, 1914, from eating 2.755 pounds of pods. This material had been collected previously and dried, but the weight as given is the green weight, as the loss from evaporation was known. These were pods in which the seed was not yet ripe. Sheep No. 301 died on August 28, 1914, from eating 2.041 poujids of pods which were collected after they had shed most of their seed; a few seeds, however, remamed attached to the pods. The weight given is the dry weight, as there was no way of estimating the loss of water in drying. In all the other cases much smaller quantities were fed, and no intoxication resulted. It can only be said that the pods are distinctly toxic, but the dosage is much greater than of the seeds. It may be added in this connection that in 1913 a careful compu- tation was made of the relative weights of the seeds and pods in the fruit, and that, based on the result of this w^ork, the toxic dose of pods would be 3.4 pounds. Without much doubt the toxicity of the pods varies at different seasons and probably is much reduced in the dried pods remaining attached to the plants in the late summer and fall. TOXICITY OF LUPINE FRUIT FOR SHEEP. By "fruit" is understood the pods with the contamed seeds. A considerable number of experiments were made to determine the toxicity of the fruit as compared with the seed. Table 5 gives the results of these experiments. The term "Seed heads" means the fruits and the stems bearing them. In the cases listed under "Fruit, fully developed," the pods were picked from the stems. The last four feedings under "Fruit, fully developed" were of very poor, locoed animals; consequently, the dosage (as computed LUPINES AS POISONOUS PLANTS. 33 according to weight) woiJd be distinctly different from that com- puted for the same animals iji a normal, healthy condition. Tliis may possibly explain why in the cases of Nos. 251 and 280 the dosage, computed on the basis of a lOO-poimd animal, so much exceeds the letlud dose shown in the precedmg experiments. For example, sheep No. 280 weighed 99 pounds earlier in the season, wliile at the time of the experiment it weighed only 84 pounds. If the dosage of material given September 4 were computed on the assumption that the animal had its original weight, it would reduce the amoiuit given m the table to approximately the toxic or lethal dose of the preceduig animals, and as the margin between no symptoms and toxicity is so small this animal woidd not differ materially from the othere. Table 5. — Sheep given forced feedings of lupine fruit in 1914- Fped and animal. Date fed. Pounds fed per 100 pounds of animal. Uasult. Friut, fully developed: No 292 July 16 0.882 .441 1.322 1. 7ti4 1.543 1.433 1.543 1.433 1.763 1.543 1.541 1.761 1.901 1.033 Not sick No 291 Jidy 17 Do July 18 Do. No 238 July 20 .. . Do No 269 July 23 Not sick No. 240 July 24 Svmpt()ni.s. Not sick. No 250 July 25 . . Death No 231 Aue 29 Not sick No. 235 Au|:3i::::::::;:: Do. No. 251 Sept. 2 ...... Do. No 280 Sept 4 Do. Seed head.s, hilly developed: No. 255 July 2^29 Do. It is evident from Table 5 that approximately 1 \ pounds of fuUy developed fruit will produce symptoms or death in a 100-pound sheep — that is, it takes three times as much of the fruit to poison as of the seed. SYMPTOMS. Some of the sheep poisoned by lupine, froth at the mouth, but this is by no means a universal symptom. The most noticeable and significant symptom is the character of the breathing. In the milder cases the brea tiling is heavy and labored, subsiding into a condition of coma in which the animal may contume for a long time, snoring as though in a deep sleep. If able to stand, the animal may fall over in its sleep. In the more acute cases, there are severe attacks of dyspnoea, duruig which the animtil tlu-ows itself about violently in its attempts to breathe. During these attacks the tongue and mouth become cyanotic from the congested peripheral blood ves- sels. Sometimes in these attacks of dyspnoea the animal dies in convidsions in which the limbs are extended rigidly, much as when poisoned by strychnin. In other cases the condition of coma deep- 34 BULLETIlSr 405, V. S. DEPARTMENT OF AGEICULTURE. ens until the animal dies without a struggle. The convulsive attacks of dyspnoea, however, may he considered typical of lupine poisoning. Drooping of the ears is noticeable in the early stages of the poisoning. In many cases the poisoned animal is contmually pushing its head agamst surroundmg objects. In corral cases the sheep pushes agamst the fence, lowering its head so that sometimes the animal almost stands on its head. These attitudes are shown in Plate III, figures 1 and 2. If moved from one point it may immediately push up against the fence in another place, sometimes throwing its head f,y^, Aj^ _^^ through an openmg and remaining in that position. Sometimes the head wiU be swung rhythmically from side to side. Generally when sheep become af- fected on the range they run about in a frenzied way, butting into other animals and objects. Handling the animals under such conditions excites them to such an ex- tent as seriously to interfere with their chances of recovery. When attempts were made to administer remedies by drench- ing, it was found that the animals lost more by the increased ex- citement than they gained from the remedy. If the sheep does not die in the period of excitement, it staggers until it falls, then lies in a stupor, which in the fatal cases gradually grows deeper. The pulse and respiration are very high in the acute stages of the intoxication, but later are not very different from normal, except that the pulse rate is frequently increased just before death. The intoxication produces no effect on the temperature, but in long- continued cases the temperature gradually faUs, sometimes to be- tween 98° and 99° F. The curves (fig. 2) showing the changes in 1 T^ / /?£ S/ ^W y\7 70. V 1 o ■^ 1 , __ _ ' ' — ' ' \ 1 \ T£. -M, 0£ yp/^ ^TUA =5f- \ \ — __ " ~ " " Fig. 2. — Curves showing the changes in pulse, respiration, and tem- perature of sheep No. 1S5. LITPJNES AS POISONOUS PLANTS. 35 the rate of tlie pulse, respii-atioii, and temperature of sheep No. 185 are fairly typical of the cliauges wliieh ordinarily take place. Associated w^ith the condition of excitement there is frequently more or less violent trembling. Nausea is not often exhibited. Bloating occurs in some cases, probably being more likely to occur when the sheep eat very largely of lupine leaves. Especially characteristic of lupine poisonmg are: (1) Excitement, leading to running about and butting into other objects; (2) con- vulsions, accompanj-ing the attacks of dyspnoea ; and (3) heavy breath- ing, sometimes accompanied by snoring. There is considerable variation in the length of time which elapses between the feeding of lupine and the incidence of s\Tiiptoms of poison- ing. In some cases symptoms appeared in 1 or 2 hours, while there were other cases m whicli nearly 24 houi-s passed before symptoms were noticed. It is evident that namination does not necessarily precede the symptoms; in fact, there was no evidence that rumination occurred in any of the experuuental sheep, althougli as they were not under constant observation it could not be said positively that rumi- nation never took place. It can be seen from the experuuental work tliat sheep upon the range, when poisoned by lupine, may not exhibit symptoms until they have left the source of their trouble far behind. In the autopsies, the peripheral blood vessels were found strongly congested. The left heart was usually strongly contracted, and upon the surface of the heart in most cases were petechia\ The lungs were congested, and sometimes the liver. Tlie blood vessels of the brain were somewhat congested, and generally the blood vessels of the inner waU of the ileum were more or less congested. The immediate cause of death is evidently respiratory paralysis. Death may follow very quickly after the first symptoms, or the ani- mals may live for 2 or 3 days. As noted in the description of the experiments of intraperitoneal injection of lupine extracts in mice, the animals died of respiratory paralysis, showing symptoms which were comparable with those ex- hibited by sheep. The preceding details of sjmptoms are those exhibited by sheep. The experiments with horses were so few that no complete picture can be given. The distinct symptoms noted were twitcliing of the surface muscles, constipation, duUness, and a tendency when walking to lift the fore feet high. Dr. A. D. Knowles, of Butte, Mont., has recently treated some interesting cases of lupme poisoning of horses. Dr. Knowles has made a very careful study of these cases and has done some experi- mental feeding, makuig autopsies and having microscopic prepara- tions made of the diseased organs. These horses exhibited symptoms 36 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTURE. comparable with the "ictrogenic" poisoning reported in Germany, especially noticeable being the atrophy of the liver accompanied by a yellowing of the connective tissues. While some American authors have distinguished between "acute" and "chronic" lupine poisoning, their statements appear to have been drawn from European sources, and Dr. Knowles has apparently been the first to note and record definitely cases which can be diag- nosed as instances of "lupinosis" or ictrogenic poisoning. The clear- cut evidence presented by Dr. Knowles seems conclusive and makes it probable that other similar cases will be found, although it does not seem likely that lupine causes large losses of horses in the ag- gregate. PATHOLOGY. Some typical pathological material from the autopsies was exam- ined by Dr. Formad, of the Bureau of Animal Industry. A large amount of material remains for examination, which may be made the subject of a future report. The general character of the pre- liminary report was confirmatory of the results of the macroscopic examination of the cases. There was fullness and congestion of the pulmonary capillaries. The hepatic cells showed the presence of a mild degree of cloudy swelling and some oedema. The kidneys showed a slight degree of cloudy swelling of the epithelium, and iji some cases fullness between the convoluted tubules of the cortex and overdistension of the capillaries of the medulla accompanied in places by outwandering of the leucocytes and diapedesis of the red-blood corpuscles, indicatmg a marked congestion. COMPARISON OF "LUPINOSIS" AND POISONING OF SHEEP BY AMERICAN LUPINES. The symptoms of lupinosis are described in detail by a number of European authors, e. g., Ziim (1879), Arnold and Schneidemuhl (1883), Roloff (1883). Summaries are given by Dammann (1902, p. 340-341) and Hutyra and Marek (1913, p. 524-525). The characteristic symptoms are : (a) Loss of appetite. (6) Fever in the first stages of the disease. (c) Weakness. (d) Cerebral excitement; thrusting the head against a wall and into corners. (e) Gnashing of teeth. (/) Pain in hind part of body. (g) Diarrhea; ill-smelling excrement. (h) Sometimes bloody urine, containing bile and albumen. (i) Yellowing of conjunctiva and visible parts of mucous membranes in most cases, but not in all. 0') In some cases swelling of ears, eyelids, lips, and nose. LUPINES AS POISONOUS PLANTS. 37 (it) In autopsies there is seen a citron-yellow color of the body tissues, hemorrhaj^es in various parts of the body, especially in the mucous membranes of the alimentary canal, the peritoneum, omentum, mesentery, the epicardium and endocardium, frequently fullness of gall bladder, generally an acute yellow liver atrophy, while in other cases the whole picture presents an appearance of acute phosphorus poisoning. The German authors distmguish between acute and chronic cases, the symptoms bemg the same, but ui the latter the liver exhibits chronic interstitial hiflammation, leaduig to atrophy of the organ, this beuig accompanied by nephritis and enlargement of the spleen. It will be noticed that the laboratory results obtained by Sollmann and by Clawson and Black agree very well wdth the field experiments with sheep, but differ very distinctly from the symptoms of lupmosis. The fever and jaundice which are especially characteristic of lupi- nosis have never been observed in sheep in America, either in experi- mental feedmg or in poisoning upon the range. It must be con- cluded that ictrogen is not the cause of loss of sheep on the ranges of the United States, but that the poisonhig is due to the alkaloids in the lupmes. The symptoms ui the corral experiments and hi range cases are distinctly those of alkaloidal poisonhig. The question naturally arises as to the explanation of the difference between the poisonhig of animals as exliibited in Germany and m the United States. The luphies examhicd in Germany possess alkaloids which are similar to those found m the American lupines, if not identical with them, and yet few clear cases of alkaloidal poisonhig of domestic aninnds have been reported, while in America there has been no poisonhig from ictrogen. In the absence of any determination of what ictrogen really is or how it; is formed, only a hypothetical explanation can be given. If it is granted that ictrogen is the cause of luphiosis and if the opmion is accepted, wliich seems to be held by the later authors, that ictrogen is formed by the action of microorganisms upon the lupme, a possible explanation lies hi the different conditions of the countries. The European lupines are cultivated plants, grown and handled like hay. The poisoning cases are caused by lupme that is exposed in the mass, and sometimes under conditions favorable to the growth of microorganisms. The American lupines are wdd plants, which grow in a somewhat scattered manner; they are not collected hi masses, and consequently do not have an especially favorable environment for the growth of microorganisms. More- over, it is very possible that the particular organisms which produce the toxic substance in Europe are not present hi this country; of this notliing can be said positively, for no one has yet been able to demonstrate that any specific organism or group of organisms is responsible for the hypothetical substance ictrogen. Therefore, on the supposition that there is such a substance as ictrogen, or lupino- 38 BULLETIN 405, U. S. DEPARTMENT OF AGEICULTURE. toxin, it seems possible that it would not be produced in America, at least under range conditions. The fact that there is so httle evidence that domestic animals in Europe suffer from the alkaloids of lupine may be explained by the different way in which the animals are handled. It is shown else- where in this paper that lupine poisoning of sheep on the western ranges is ordinarily associated with deficiency in the food supply. Rarely, if ever, are well-fed sheep poisoned. It may be assumed that the sheep in Germany that feed upon the lupine are staU-fed or pasture-fed and eat somewhat at leisure, so that seldom would they be Ukely to reach the toxic limit in a single feeding. In this connec- tion, however, it may be noted that some of the symptoms men- tioned by the German authors resemble those of alkaloidal poisoning, and, granted that ictrogen is the principal cause of the losses, it is possible that there is a certain amount of alkaloidal poisoning in addition. This would account for the nervous symptoms described by the German authors, for these correspond to the phenomena exhibited by western sheep suffering from the lupine alkaloids. It should be noted in this connection that the work of Dr. Knowles mentioned on page 35 seems to show that under some conditions ictrogenic poisoning of horses may occur in America. The exact relationship between poisoning by lupine alkaloids and ictrogenic poisoning is far from clear, and it is to be expected that the chemical investigations which are now being carried on by the United States Department of Agricidture will aid in clearing up this subject. REMEDIES. It was hoped that some remedy might be found by which recovery from lupine poisoning might be aided, but the results of the experi- mental work in this direction were disappointing. Whisky, gin, and atropin were tried, with no beneficial results. Caffein and Epsom salts were used to increase excretion, but without any advantage. Tannic acid and sodium bicarbonate were used as antidotes. In the publication on Zygadenus,^ there is a discussion of reasons why the use of antidotes in a drench in any ordinary method of administra- tion should not be expected to be beneficial. As in the work on Zygadenus, experiments were made of giving sodium bicarbonate in frequently repeated doses. This was tried in four cases (sheep Nos. 297, 254, 296, and 269). Sheep No. 269 received 0.772 pound of seed and died in spite of the remedy, but sheep No. 296 received 0.666 pound, considerably more than the toxic dose, and was not sick. This animal received the sodium bicarbonate every half hour, while sheep No. 269 received it at hour intervals. There seems to be little doubt, as in Zygadenus poisoning, that if the sodium bicarbonate 1 U. S. Dept. of Agr. Bui. No. 125, p. 41. LUPINES AS POISONOUS PLANTS. 39 can be administered at intervals frequent enough to (^atch the toxic principle as it enters the fourth stomach, recovery may bo aided. This is of considerable theoretical interest, and the method might be used in order to save an especially valuable animal, but, of course, range animals can not be treated in this way, for the herder may have a large number of sheep sick at the same time. It is not imusual for 200 or 300 cases to occur suddenly, and any remedy which involves the administration of more than one or two doses is useless. Herders frequently bleed sheep poisoned by lupine and claim good results. There seems no logical reason for this, however, and the experience of the WTitcrs at the field station leads them to consider bleeding as harmful rather than beneficial. RANGE CONDITIONS UNDER WHICH SHEEP ARE POISONED. It must be recognized that corral experiments, while superior to laboratory M'ork in unravehng the complex problems of plant poison- ing of domestic animals, do not cover tlio conditions of range poison- hig. It is sometimes very diflicult to decide to what extent the results of intensive corral feeding can bo used in the explanation of range phenomena. Laboratory and corral experimentation are, of course, essential in such a study, and may give, in fact do give, fundamental information. An intimate acquaintance with range conditions is, however, necessary for the practical elucidation of these problems. Such an acquaintance with range conditions is somewhat difficult for the scientific investigator to acquire. Sheep are grazed in locations situated at long distances from regidar avenues of travel or communi- cation, and they are also moving from place to place. Cases of poisoning are reported, perhai)s, some chiys after the trouble has occurred, and investigation at that time is likely to be useless. It is very difficult for the investigator so to locate himself as to be able to see these cases when they occur. These difliculties doubtless explain why there has been so little exact knowledge of the conditions sur- rounding the losses. There has been, moreover, no way of placing a correct valuation on the reports made by sheep herders and o^vners. The average sheep herder does not have a high order of inteffigence, and this has led to an miderestimate of the testimony of these men, for the fact has been overlooked that many of them are keen observers with a practical knowledge of conditions far superior to that of the average scientific investigator. The writers of this paper have had long and intimate acquaintance with the western stock ranges, but they have frequently been put to shame by the wonderful, almost instinctive, readiness with wliicli an experienced sheepman will unerringly recognize slight symptoms of disease in the members of his flocks. The writers were fortunate in being able to observe many 40 BULLETIN 405, U. S. DEPARTMENT OP AGKICULTUKE. range cases, and the conditions under which poisoning may occur seem now quite clear. It was early recognized that lupine poisoning ordinarily occurs only when hungry sheep graze upon the plants. WeU-fed bands are rarely, if ever, poisoned. This statement, it may be said in passing, can be made general and covers practically aU poisonous plants. If sheep are taken from the cars and turned into a pasture abundantly supplied with lupine, disastrous results are Hkely to occur. In July, 1914, 400 sheep, out of a band of 4,000, were lost near Lakeview, Oreg. The matter was investigated by Mr. Norman G. Jacobson, of the Forest Service, who found that the sheep had been driven 34 miles in four days with a scarcity of forage. On July 25, after a day's drive of 10 miles, they were turned into a 10- acre pasture which, investigation showed, contained httle but sage- brush and lupines, and the lupines were in pod. The sheep, of course, ate the lupines and with resulting loss. Many losses have occurred in the fall when sheep are coming down from the mountain ranges and have been caught by snow. On such occasions the fall of snow may cover the grasses, but leave the lupines exposed. Hungry sheep coming upon such an area may eat enough of the lupines to produce poisonmg. In the faU of 1913 a sheep owner in Montana lost 300 sheep in this way. An area in the Caribou National Forest was investigated where aimual losses have occurred. It was found that the sheep coming from the mountains pass through thick patches of lupine and eat it greedily. The fact that the lupines are in pod at the time of the drive makes the matter worse. In 191 1 , an especially disastrous year, one outfit lost 1,000 head in this locahty. And yet, in spite of these kno-v^Ti cases of severe loss, sheep some- times graze on lupine through a good part of the season and with no harm. Except as they are especially hungry sheep rarely, if ever, eat enough of the lupine to cause trouble. Poisoning is much more hkely to occur if sheep are hurried over a lupine area, for then in their eagerness and jealousy of each other they seize upon the lupines, which are more easily reached than the grasses. Generally speaking, it is much better to drift sheep over a lupine area than to drive them. It may be noted that sheep that are new to a locality are much more likely to eat too much of the lupine than those that are accustomed to the country. An attempt was made in 1912 to demonstrate in an experimental way that hungry sheep may be poisoned when they feed upon lupine. A bunch of 11 sheep were kept without food for 36 hours and then, durmg one day, were driven 12 to 15 miles with very little opportu- nity to eat. About 5 p. m. they were brought to a thick lupme patch and allowed to graze. They fed imtil about 8.30 p. m., when they LUPINES AS POISONOUS PLANTS. 41 were bedded down. They were up and feeding again at 12.15 a. m. and were grazing most of the time until 6.30 a. m., with the excep- tion of the hour from 4 to 5. To the disappointment of the observ- ers none of the animals was poisoned. It was noticed, however, that while a good deal of lupine was eaten they did not take to it greedily and preferred the grass, which was in fair abundance. In tliinking over the experiment later, it seemed probable that the fact tliat the sheep were allowed to feed freely, combined \vith the abundance of grass, might explain the lack of results. It was there- fore decided to repeat the experiment vnth the difference that the sheep should not be allowed to feed freely upon a lupine patch, but sliould be kept moving back and forth, the idea being that in this way they might snatch at the lupine as the most promment plant. An experiment of this kmd was tried July 31, 1914. Thirty-six sheep were corralled at night and kept in until 2 p. m. the next day with no ft)od. At 2 p. m. they were driven about a mile to a lupine patch having an abundance of pods and seed. It proved to be an unfavorable time for such an experiment, for it was very hot and tlie sheep would not feed until about 7 p. m. They grazed until about 8 p. m. and were kept on the move all this time. They were driven back to the corrals. The time of grazing was so short that it was assumed the experiment was a faUure, and tlie sheep were not ob- served duruig the night. The next morning sheep No. 241, which had been observed as one of tliose eating th(> most lupme, was found douTi, and a little later it died, the symptoms and autopsy mdicat- rng tliat it was, without doubt, a lupine victim. The outcome of tliis experiment was considered to be a confirmation of tlie general ex- planation of range poisoning as given before. TREATMENT OF RANGE ANIMALS TO AVOID POISONING. From what has been said of the conditions imder wliich range poi- soning occurs, it is evident that much of the loss can be prevented by proper management of the bands. Sheep should never be taken from the cars to a pasture having much lupine. It is cheaper to buy hay. After long drives witli insufficient forage avoid grazing grounds wliich are covered with lupine. If it is necessary to drive sheep over lupine patches, do not hurry them, but allow them to spread out and drift across. Special care should be taken in the faU, when the grass may be covered by a fall of snow. In the treatment of the flocks remember the general fact, which is applicable in regard to all poisonous plants, that well- fed sheep are not likely to eat injurious plants. Conditions under which sheep get ravenously hungry should, if possible, be avoided. Herders should recognize the fact that the pods and seeds are espe- cially poisonous and that, consequently, poisonuig is more likely to 42 BULLETIN 405, U. S. DEPARTMENT OF AGRICULTURE. occur at the time when the plants are in fruit and in seasons when the fruit is most abundant. In very dry seasons frequently little fruit is matured, while a wet season, especially a wet spring, may cause a heavy production of fruit. SUMMARY. (1) Lupines have been cultivated and used from the time of the ancient Greeks and Romans, but their poisonous properties have been recognized only in very modern times. Heavy losses of domestic animals were reported in northern Germany in 1872 and the suc- ceeding years. (2) While chemists have shown the presence of poisonous alkaloids in the lupines, the losses in northern Germany have been considered by investigators as due not to the alkaloids but to a hypothetical substance known as ictrogen. (3) An investigation by Dr. Sollmann showed the presence of alkaloids in American lupines, and pointed to the probability that most, if not all, the poisoning of live stock in America was due to these alkaloids and not to ictrogen. (4) Extended field work has verified the conclusions of Sollmann and has shown that all aerial parts of the lupines examined are poisonous, the seeds being the most toxic, then in order the pods and leaves. This has been confirmed by preliminary experiments with extracts upon mice. (5) The toxic substance is excreted by the kidneys; the intoxica- tion is not cumulative, and animals may eat comparatively large quantities with no ill results, if the toxic limit is not reached at any one time. Inasmuch as the toxic and lethal limits are nearly the same, the prognosis for poisoned animals is not favorable. (6) There is no form of remedial treatment that can be used ad- vantageously for range animals. Poisoning in most cases can be avoided, even where the plant is abundant, by careful handling of the flocks, especial care being taken to see that hungry sheep are not grazed on fields where there is much lupme. LITERATURE CITED. Arnold, Carl, and Lemke, Carl. 1881. Beitrair zur Klarstellung der Ursache dor Liipinose. In Deut. Ztschr. Thiermed., Bd. 7, Heft 4, p. 251-265. and Schxeidemuhl, Georg. 1883. Vierter Beitrag zur Klarstellung der Ursache und des Wesene der Lupinose. In Jahresber. K. Thierarzneischule, Hannover, Ber. 15, 1882/83, p. 108-116. Baumert, Georg. 1886. Ueber den "Bitterstoff," das Ictrogen und Lupinotoxin der Lupinen. In Arch. Pharm., Bd. 224, Heft 2, p. 49-59. Bellini, Ranieri. 1876. Deir avvelenamento prodotto dai pemi del lupine. In Riv. Sper. Fren. e Med. L^g., ann. 2, fasc. 5/6, p. 581-€27. Bergh, G. F. 1904. Ueber die Alkaloide der perennierenden Lupine. In Arch. Pharm., Bd. 242, Heft 6, p. 416-440, 1 pi. Beyer, Ad. 1871. Ueber einige Bestandtheilo des gelben Lupinenaamen. In Landw. Vers. Stat., Bd. 14, p. 161-176. CaLLSEN, JiJROEN. 1899. Uebor die Alkaloide der Samen von Lupinus angustifolius und von Lupinus perennis var. polyphyllus. In Arch. Pharm., Bd. 237, Heft 8, p. 566-595. Oassola. 1834. Note eur la lupinine. (Abstract by Julia-Fontenelle, with note.) In Jour. Chim. M6(\. Pharm. et Tox., t. 10, p. 688-689. For Gorman translation see Ann. Pharm. [Liebig], Bd. 13, Heft 3, p. 308-309, 1835. Chesnut, V. K. 1899. Preliminary catalogue of plants poisonous to stock. In U. S. Dept. Agr., Bur. Anim. Indus., 15th Ann. Rpt., 1898, p. 387-420, fig. 38-69. and Wilcox, E. V. 1901. Stock-poisoning plants of Montana. A preliminary report. U. S. Dept. Agr., Div. Bot. Bui. 26, 150 p., 36 pi. CORNEVIN, C. E. 1893. Des Plantes V^n^neuses et des Empoisonnements qu' elles Det^rminent. 524 p., illus. Paris. Dammann, Carl. 1902. Die Gesundheitspflege der landwirtschaftlichen Haussaugetiere. Aufl. 3, 873 p., 74 fig., 20 col. pi. Berlin. Davis, L. S. 1897. Die Lupanine der weissen Lupine. In Arch. Pharm., Bd. 235, Heft 3, p. 199-217. Gemma, A. M. 1882. Studi Sperimentali e clinici suU' azione della lupinina amorfa impura. In Gaz. Med. Ital. Lomb., v. 42 (s. 8, t. 4), no. 14, p. 147-149. 43 44 BULLETIN 405, U. S, DEPARTMENT OF AGRICULTURE. HuTYRA, Ferencz, and Marek, Jozsef. 1913. Special Pathology and Therapeutics of the Diseases of Domestic Animals. Authorized Amer. ed. from the 3d rev. German ed., J. R. Mohler and Adolph Eichhorn, editors, v. 2, 163 illus., 5 pi. Chicago. KuHN, Julius. 1880. Die Schmarotzerpilze der Lupinenpflanze und die Bekampfung der Lupin- enkrankheit der Schafe. In Ber. Physiol. Lab. u. Vers. Anst. Landw. Inst. Halle, Heft 2, p. 115-128. Landerer. 1852. Ueber den Bitterstoff aus Lupinus. In Neues Repert. Pharm., Bd. 1, Heft 10, p. 445-447. LlEBSCHER, G. 1880. Beitrag zur Klarlegung der Frage nach den Ursachen der Lupinenkrankheit der Schafe. In Ber. Physiol. Lab. u. Vers. Anst. Landw. Inst. Halle, Heft 2, p. 53-114. LoWENTHAL, JULIUS. 1888. Ueber die physiologischen'und toxicologischen Eigenschaften der Lupinen- Alkaloide. 26 p., Konigsberg. Inaugural-Dissertation. MUENK, GUSTAV. 1914. Beitrage ziu- Kenntnis der Bestandteile und Wirkungen der Lupinensamen. In Landw. Vers. Stat., Bd. 85, Heft 6, p. 293-416. Plinius Secundus, Caius. 1856. The Natural History of Pliny. Tr . . . by . . . John Bostock and H. T. Riley, v. 4. London. Raimondi, C. 1891. Sur les principes actifs et toxiques du lupin. In Arch. Ital. Biol., t. 15, fasc. 2, p. 246-253. ROLOFF, FRIEDRlfcH. 1883. Ueber die Lupinose. In Arch. Wiss. u. Prakt. Thierheilk., Bd. 9, Heft h, V- 1-54. Schmidt, Ernst. 1897. Ueber die Alkaloide der Lupinensamen. In Arch. Pharm., Bd. 235, Heft 3, p. 192-198. 1904. Ueber die Lupinenalkaloide. In Arch, Pharm., Bd. 242, Heft 6, p. 409-415 Slade, H. B. 1903. Some conditions of stock poisoning in Idaho. Idaho Agr. Exp. Sta. Bui. 37, p. 159-190, illus. Wilcox, E. V. 1899. Lupines as plants poisonous to stock. In Mont. Agr. Exp. Sta. Bui. 22, p. 37-45. Literature, p. 43-45. WiLLSTATTER, RiCHARD, and FOURNEAU, ErNEST. 1902. Zur Kenntnis des Lupinins. In Arch. Pharm. , Bd. 240, Heft 4, p. 335-344. ZiJRN, F. A. 1879. Massenerkrankung von Schafen durch den Genuss befallener Lupinen, In Vortr. Thieriirzte, S. 2, Heft 7, 29 p. (p. 251-277), 6 fig. PUBLICATIONS OF THE U. S. DEPARTMENT OF AGRICULTURE RELATING TO POISONOUS PLANTS. AVAILABLE FOR FBEE DISTRIBUTION BY THE DEPARTMENT. Zygadenus, or Death Camas. (Department Bulletin 125.) Larkspur Poisoning of Live Stock. (Department Bulletin 365.) Larkspur, or " Poison Weed." (Farmers' Bulletin 531.) Prevention of Losses of Live Stock from Plant Poisoning. (Farmers' Bulletin 720.) FOR SALE BY THE SUPERINTENDENT OF DOCUMENTS. GOVERNMENT PRINTING OFFICE. WASHINGTON. D. C. Cicuta, or Water Hemlock. (Department Bulletin 69.) Price, 10 cents. The Poisonous Action of Johnson Grass. (Bureau of Plant Industry Bulletin 90, Pt. IV.) Price, 5 cents. The Larkspurs as Poisonous Plants. (Bureau of Plant Industry Bulletin 111, Pt. I.) Price, 5 cents. The Supposed Relationship of Wliite Snakeroot to Milksickness, or "Trembles." (Bureau of Plant Industry Bulletin 121, Pt. I.) Price, 5 cents. Mountain Laurel, a Poisonous Plant. (Bureau of Plant Industry Bulletin 121, Pt. II.) Price, 5 cents. Results of Loco- Weed Investigations in the Field, Laboratory Work on Loco- Weed Investigations. (Bureau of Plant Industry Bulletin 121, Pt. III.) Price, 5 cent.s. Barium, a Cause of the Loco- Weed Disease. (Biu-eau of Plant Industry Bulletin 129.) Price, 10 cents. The Relation of Barium to the Loco- Weed Disease. (Bureau of Plant Industry Bul- letin 246.) Price, 10 cents. Menziesia, a New Stock- Poisoning Plant of the Northwestern States. (Bureau of Plant Industry Circular.) Price, 5 cents. The Loco- Weed Disease of the Plains. (Bureau of Animal Industry Bulletin 112.) Price, 35 cents. The Stock-PoisoPLQg Plants of Montana. (Division of Botany Bulletin 26.) Price, 25 cents. The Loco- Weed Disease. (Farmers' Bulletin 531;.) Price, 5 cents. Stock Poisoning Due to Scarcity of Food, (Farmers' Bulletiia 536.) Price, 5 cents. 45 WASHINGTON : GOVER.VMB.VT PKINTING OFB'ICB : 1916 ADDITIONAL COPIES OF THIS PUBLICATION MAY BE PROCURE!) 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