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ALBERT R. MANN 
 LIBRARY 
 
 New York State Colleges 
 
 OF 
 
 Agriculture and Home Economics 
 
 
 ire 
 
 Cornell University 
 
1 
 
 Date Due 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 Library Burca 
 
 J Cat, No. 1137 
 
 
 r~r, -.^ Cornell University Library 
 SB 741.G8B42 
 
 Sur ('excitation a tramantism, le paras 
 
 3 1924 002 926 651 
 
Cornell University 
 Library 
 
 The original of this book is in 
 the Cornell University Library. 
 
 There are no known copyright restrictions in 
 the United States on the use of the text. 
 
 http://www.archive.org/details/cu31924002926651 
 
Sur 1' exoitatlon a tramantism, le parasltismus 
 et I'eooulement gomneux chez les amygdales. 
 
 Arch. Neer. d. Soi. Nat. 11:184:199. 1905. 
 
 (On the response to injury, parasitism and 
 on the flow of guin, in the peach family). 
 
 by 
 
 H. YJ. BEIffimilTCE: and A. A. SAilT 
 
 Translated by 
 
 P. J. Anderson, 
 
 Fellow, Department of Plant Pathology. 
 
 February 1912. 
 5 
 
'06 Beijerinck, M. W. and Rant, A. A, 
 
 Sur 1' excitation a tramantism, le parasitismus et 
 I'ecoulement gommeux chez les amygdalees. Arch. Ueer. 
 d. Sci. Hat. 11 : 184-199. 19Q6, 
 
 Corynetim beigerinckij (probably same as Clasterosporiiun 
 amygdala arum) a parasite on the bark of the almond tree, causes 
 an abundant flow of gum when inoculated into the bark. 
 
 But in the former researches on this subject, sufficient 
 attention has not been paid to the relatj^on which exists between 
 
 r 
 
 the flow of gum and the excitation produced by wounds, noX5 be- 
 tween that excitation and parasitism. light has been thrown 
 on this subject by the experiments which the author ]^as carried 
 on with A. A. Rant and a preliminary sketch of these given in 
 this article. 
 
 In these experiments, peach and almond trees were used 
 because they are very sensitive to wounds and easily re-act 
 by an abundant flow of gum. 
 
 1. Lesions of the Oambium of the Young Green Branches . 
 
 When the young twigs of the peach were wounded to the 
 cambium, drops of gum appeared on these in less than a week. 
 The flow at the tip of the twig is weak, then for a zone of 1-E 
 decimeters it is greatest, below this it decreases and finally 
 disappears completely. This region of greatest flow seems to 
 be slightly below and not identical with the region of maximum 
 longitudinal growth. 
 
 The explanation of this is that the flow is in relation 
 to the growth of the cambial thickness, both the cambium and 
 
E 
 pro cambium, and in the parts which are distant this growth is 
 weak and since the other paranchyraatous tissues are unahle to 
 transform themselves into gum, we have no gumming here. 
 
 Those portions of the branch which have already formed 
 a cork layer do not exude gum usually when wounded in the cam- 
 bium in summer. But Ihis is not always the case, it depends on 
 the season, so that we may conclude that the flow of gum depends 
 on the physiological condition of the tissues. 
 
 Microscopical examination of the wounds shows that the 
 gum comes from the canals Just inside the cambium circle and 
 anatomically then the gum corresponds to secondary sap wood, 
 which has been arrested in its development and has become liquid 
 while it was yet in the cambial or cellular state. The for- 
 mation of ducts results from the fact that the medullary ray 
 cells of the cambium are not so easily transformed into gum as 
 the wood cells. The gummosis, however, may involve also the 
 forming medullary rays and then there are fonmed flat gummi- 
 ferous cavities or large elliptical canals. 
 
 The situation and extent of the canals depends on the 
 nature of the wound. When it is a small wound the canals 
 are in the immediate neighborhood of the wound, but when it 
 extends to the pith the canals are on the whole perephery. 
 The canals attain a length of 1-10 mm. and their extremeties 
 occupy an ellipse of which the lower focus lies on the wound. 
 Thus the traumatic excitation may be observed more above than 
 below the wound, and it extends further longitudinally than 
 laterally. 
 
 Summing up then we may say that the phenomenon depends 
 on a pathologic transformation of the embryo woody tissue 
 
3 
 caused by a traumatic excitation. 
 
 S. Lesions of the Cambium of More Mature Branches . 
 
 When branches of the trees are brought in during February 
 and March and their bases put in the water in a warm chamber it 
 will be noticed in about S-IO days that all the branches cease 
 to exude gum at the cut, but the gum flows from wounds which are 
 made in the branches, especially when these are oblique or trans- 
 verse. 
 
 Like wounds at the same time made in the open air do not 
 flow, probably because the temperature is too low to make possible 
 the biochemical process necessary to that phenomenon. On the 
 other hand when these branches are wounded in the summer, they do 
 not exude gum, either out of doors or when brought in. It will 
 thus be seen that it depends upon the physiological state of the 
 cambium in the spring time. But it is not thus when the wound 
 is infected with Coryneum, which always excites an abundant flow 
 of gum. 
 
 This is what is observed when one examines in February the 
 cambial ring near a cut from which gum has been flowing; First, 
 one notices that the cambium at that season consists of several 
 layers of cells. The line of demarkation-*- between the bark 
 and the wood is not distinct. But that which is most interesting 
 is the formation of gummiferous canals in the cambial cloak, in 
 the neighborhood and even at considerable distance from the 
 wound, composed of several (4-6) layers of cells, in the same 
 manner as we have described for the young green branches. On 
 account of the lack of differentiation it could not be definite- 
 ly determined that the canals were in the sap wood and not in 
 
4 
 the "bark, but the author was of that opinion. 
 
 In the older branches also it was observed that the 
 guimniferous tubes occupied an ellipse with the wound at the 
 lower focus. One can easily understand this when he considers 
 
 > 
 
 that the excitation is spread in the xylem with the ascending 
 sap. Aderhold's observation that the infections of Coryneum 
 of wounds made above a ring without bark gave more of a flow 
 of gum than those below the ring may be explained by the fact 
 that the descending sap carried the nourishment (which is also 
 necessary to the fungus) above the ring, but not below it. 
 
 Then we arrive at the same conclusion in regard to the 
 older branches as the younger ones; the flow of gum is due 
 to the liquefaction of the embrionic sap wood, produced by 
 traumatic excitation. 
 
 The fact that some cavities are found even in the older 
 wood is not contrary to this statement since it is probable 
 that the wood was in the embryonic state when the cavities 
 were formed. The completely formed wood never liquefies. 
 Excitations produced by poisons or burning . 
 
 Although we do not know at present just what we should 
 understand by traumat-icexcitation, yet it may be supposed that 
 it has to do with a mecrobiotic influence of the dicing cells 
 on the living cambium cells. One would expect then that a 
 violent poison intiDoduced into the cambium would act in an 
 analogous way or perhaps even more energetically, since its 
 influence would reach a larger number of cells. On© would 
 also suppose burning would cause the same result although more 
 feebly. 
 
5 
 The author used corrosive suhlimate as a poison, and in 
 
 summer ohtained results in 4-7 days: the punctures made in the 
 young branches of the peach, and infected with the poison gave 
 more of a flow of gum than one would expect simply from the 
 puncture. Since this poison ifi fatal to fungi and bacteria 
 the possibility of the gum coming from bacteria, for example 
 one of the gum producing bacteria, that is not culturable is 
 entirely excluded, although some authors have supposed this to 
 be the case. The great flow of gum caused by Coryneum is ex- 
 plained by the fact that it produces a violent poison which 
 acts like the sublimate, and produces a traumatic excitation of long 
 duration. 
 
 Old branches of the apricot, injured in July, easily 
 healed up wit h the formation of a callus when untreated, but 
 when treated with sublimate they gave an abundant flow of gum. 
 
 The wounds made by burning gave the same result, though 
 less marked; which is easy to understand, since the sublimate 
 penetrating slowly by defusion in the dieing cells destroys 
 new cells for a long time, farther and farther away. In the 
 case of the burnt places, however, which induced by focusing 
 the rays of the sun witli a lens, the area remains limited. 
 
 It is evident that in the center of this area there are dead 
 
 . surrounded by a zone of necrobiotic cells 
 cells, /these last having this characteristic, that the proto- 
 plasm is dead, but the enzymes and other enzymatic substances 
 still retain their activity. Clearly then the conclusion is 
 inevitable that the influences of these necrobiotic substances 
 on the living cells is the cause of the flow of gum. 
 
 These circumstances have lead us to believe that there 
 is a certain analogy between the transformation of the embryonic 
 
6 
 tissue into giim and the action of the catalylic enzyme called 
 oytase "by the physiologists, which is ahle to dissolve the 
 entire cells, and not the idea of the hotanists, by which they 
 have in view the liquefactions of the cell walls only and for 
 which the more specific name of cellulase, gelas© and prectinase 
 are more convenient. 
 
 The hypothesis expressed in 1886 that the enzymatic sub- 
 stance, causing the gum comes from the fungus Coryneum, is not 
 in accord with the actual facts, in that it may now be considered 
 as demonstrated that the excitation action of the fungus rests 
 in a poison and that it is the necrobiotie cells themselves 
 that secrete the agent of the gum. 
 
 The hypothesis that the catalytic enzymes coming from 
 the necrobiotie cells, is the cause of the gum, indirectly 
 corroborated by the fact that in the higher plants a cytolytic 
 body has been found, active in the formation of the traeheids 
 and vessels in the cellular meristem and in the procambium. 
 There, the transformation undoubtedly consists of a cytolysis, 
 in which the longitudinal liquified walls of the elements alone 
 reinains intact, while the material produced by the cytolysis, 
 consists at least partially, of a body of a gumming nature, 
 which may be found in the vessels. 
 
 From this then we see that the traumatic excitation is 
 nothing other than bringing into activity, a process which takes 
 place normally, and in fact in the very place where that power 
 is the most strongly developed (the secondary sap wood). The 
 gum produced under natural conditions is usually reabsorbed, 
 but even this is not always the case since it is often found 
 
7 
 
 in the completely formed vessels. 
 
 The author makes the following resume of this theory of 
 the flow of gma : 
 
 1. The normal plant produces cytolirtic substances 
 which contribute to the formation of vessels and tracheids. 
 
 2. This physiological gum, thus formed is usually 
 reabsorbed, but in certain cases may be found as such in the 
 
 cavities of the walls. 
 
 3. The flow of gum depends on the excessive activity 
 of the analogous cytolytic substances, produced by the necro«. 
 biotic cells, (necrobiosis meaning the cellular function which 
 remains after the death of the protoplasm, the enzymatic sub- 
 stances having kept their activity). 
 
 4. The poisons, as corrosive sublimate, or the 
 poison produced by Corjmeum, augment then indirectly the 
 cytolysis in the cambitun and in the sap wood. 
 
 Influence of Saprophytes on Traumatic Excitation 
 and the Flow of Gum in the Y oung Green Branches . Parasitism . 
 
 In the experiments it was found that when the young 
 branches were wounded in ^uly, the flow of gum took place for 
 only a short distance, but this zone differed greatly in the 
 various branches. 
 
 This seems to be the explanation : 
 
 The flow of gum is the direct consequence of a necro- 
 biotic process : all the causes which produce necrobiosis then 
 will cause the flow of gum. But, if simple wounds are suffi- 
 cient in certain cases to produce this effect, then other circum- 
 stnaces causing the death of the cells, should have the same 
 
8 
 effect. For example, the bacteria whicli do not produce any 
 specific poison ought when introduced into the tissue to cause 
 the death of the neighhoring cells by cutting off the 03?ygen 
 supply, and thus increase the flow of gum. He introduced 
 Dematium pullulans into wounds thus and found that the zone 
 of wounds producing guramosis was farther extended from the 
 apex of the twig, bu^ here the older portions still retained 
 their immunity which is entirely contrary to the effect pro- 
 duced by Coryneum. Also got the same results with Phyllos- 
 ticta persicae but not with the bacteria isolated from the 
 gum, but he is of the opinion that other bacteria could be 
 found which would produce the result. 
 
 (Here the author makes a degression of two pages on the 
 saprophytic flora of the higher plants). 
 
 As regards parasites he found besides Coryneum, which 
 was particularly active, Monilia fructigena and a Cytospora, 
 both of which produced the flow of gum. 
 
 The thing tjiat is characteristic of the parasites is the 
 great intensity of their poisoning influence. When infected 
 with Coryneum, the whole twig perished and the flow of gum 
 was confined to the zone of transition between the living and 
 the dead tissue. The only anatomical differences he observed, 
 however, was that the formation of the gummiferous canals was 
 more extensive when infected with Coryneum than when the poison 
 was used. 
 
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