CHAPTER VI. 



APPLICATIONS OF RESULTS OF RESEARCHES. 



In considering the applications of the results of these 

 researches to the explanation of the developmental 

 changes in the germplasm, and of variations, fluctua- 

 tions, sports, mutations, Mendelism, the genesis of spe- 

 cies, etc., it must be borne in mind that the investiga- 

 tions (Publications Nos. 116, 173, and the present) 

 have been of a purely exploratory character and no 

 serious attempt has been made to do more than lay a 

 substantial foundation for future investigation, theoreti- 

 cal and practical. Hence, in the present chapter noth- 

 ing more than mere suggestions will be offered in the 

 applications of the results of fundamental problems of 

 biology ; nor would more here be possible, if for no other 

 reason than the enormity of the field to be covered.* 



SPECIFICITY OF STEREOISOMERIDES IN RELATION TO 

 GENERA, SPECIES, ETC. 



These researches have as their essential basis the con- 

 ception that in different organisms corresponding com- 

 plex organic substances that constitute the supreme 

 structural components of protoplasm and the major 

 synthetic products of protoplasmic activity are not in 

 any case absolutely identical in chemical constitution, 

 and that each such substance may exist in countless 

 modifications, each modification being characteristic of 

 the form of protoplasm, the organ, the individual, the 

 sex, the species, and the genus. This conception was sup- 

 ported not only by the extraordinary differences noted 

 between the albuminous substances of venom and those 

 of other parts of the serpent, f but also by the results of 

 the investigations of Hanriot, who described marked dif- 

 ferences in the properties of the lipases of the pancreatic 

 juice and the blood; of Hoppe-Seyler and others who 

 stated that the pepsins of cold- and warm-blooded ani- 

 mals are not identical; of Wroblewsky and others who 

 recorded differences in the pepsins of mammals; of 

 Kossell and his students who found that the protamins 

 obtained from the spermatozoa of different species of fish 

 are not identical ; and of various observers who have 

 noted that the erythrocytes of one species when injected 

 into the blood of another are in the nature of foreign 

 bodies and rapidly destroyed. During subsequent years, 

 and especially very recently, data have been rapidly 

 accumulating along many and diverse lines of investi- 

 gation which collectively indicate that every individual 

 is a chemical entity that differs in characteristic par- 

 ticulars from every other. To any one familiar with 

 the advances of biochemistry and with the trend of scien- 

 tific progress toward the explanation of vital phenom- 

 ena on a physico-chemical basis, it will be obvious that 

 if the conception of the non-uniform constitution of 



*The first three sections of this chapter are reproduced, with 

 some alteration and addition, from an article that was published 

 in Science, 1914, n.s., XI., 649-661. 



fResearches upon the Venoms of Poisonous Serpents. By S. 

 Weir Mitchell and Edward T. Reichert. Smithsonian Contributions 

 to Knowledge, Publication No. 647, 1886. 

 360 



corresponding proteins and other corresponding complex 

 organic substances in different organisms and parts of 

 organisms wore found to be justified by the results of 

 laboratory investigation a bewildering field of specu- 

 lation, reasoning, and investigation would be laid open 

 a field so extensive as to include every domain of bio- 

 logical science, and seemingly to render possible, and 

 even probable, a logical explanation of the mechanisms 

 underlying the differentiations of individuals, sex, varie- 

 ties, species, and genera; of the causes of fluctuations 

 and mutations; of the phenomena of Mendelism and 

 heredity in general ; of the processes of fecundation and 

 sex-determination ; of the tolerance of certain organisms 

 to organic poisons that may be extremely virulent to 

 other forms of life ; of tumor formation, reversions, mal- 

 formations, and monsters; of anaphylaxis, certain tox- 

 emias, immunities, etc. ; and of a vast number of other 

 phenomena of normal and abnormal life which as yet 

 are partially or wholly clothed in mystery. 



Some years previous to the discovery of the nature 

 of the lethal constituents of venoms, Pasteur found that 

 there exist three kinds of tartaric acid which, because 

 of different effects on the ray of polarized light, are dis- 

 tinguished as the dextro-, Isevo- and racemic-tartaric 

 acids, the dextro form rotating the ray to the right, the 

 laevo form to the left, and the racemic form not at all. 

 When these acids were subjected in separate solutions 

 to the actions of Penicillium glaucum fermentation pro- 

 ceeded in the dextro form, but not in the laevo form, 

 while in the solution of the racemic acid, which is a 

 mixture of the dextro and laevo acids, the dextro form 

 disappeared, leaving the loevo moiety unaffected. All 

 three acids have the same chemical composition and 

 chemical properties, but differ strikingly in their effects 

 on polarized light and in nutritive properties. Identi- 

 cal or corresponding peculiarities have since been re- 

 corded in relation to a large number of substances. 

 Thus, of the twelve known forms of hexoses, or glu- 

 coses, only the dextro forms are fermentable, that is, 

 capable of being used by certain low organisms as food, 

 but not all are thus available, and, moreover, those which 

 are show marked differences in the degrees of fcrmen- 

 tability. In the case of other substances Penicillium 

 may consume the laevo form, but not the dextro form. 

 Other organisms show similar selectivity's, using either 

 dextro or laevo form, or both, but in the latter case in 

 unequal degree. Even more striking instances have 

 been recorded in the actions of poisons, as, for instance, 

 dextro-nicotine is only half as toxic as the laevo form; 

 dextro-ad renal in has only one-twelfth the power of the 

 laevo form; racemic-cocaine has a quicker and more in- 

 tense but less lasting action than the lajvo form ; the 

 asparagines, hyoscines, hyoscyamines and other sub- 

 stances have been found to exhibit marked differences in 

 accordance with variations in their optical properties. 

 With other bodies belonging to this category it may be 



