PREFACE. 



IX 



tiouship to the stereochemic modifications of the forms 

 of protoplasm which produce them. In other words, one 

 may lay down the dictum that each and every form of 

 protoplasm existent in any organism is stereocliemically 

 peculiarly modified in specific relationship to that organ- 

 ism, and that, as a, corollary, the products of synthesis 

 will be modified in conformity with the molecular pecu- 

 liarities of the protoplasm giving rise to them. It fol- 

 lows, therefore, that if the plastids of any given plant 

 be of different stereochemic structure from those of 

 others, the starch produced will show corresponding 

 stereochemic variations, and hence be absolutely diag- 

 nostic in relation to the plant. Abundant evidence will 

 be found in the pages which follow in justification of this 

 statement. Moreover, if such differences are diagnostic, 

 it is evident that they constitute a strictly scientific basis 

 for the classification of plants. 



" The research on starches was undertaken with three 

 primary objects in view: First, to determine if the hy- 

 pothesis underlying the hemoglobin investigation would 

 be supported by the stereochemic peculiarities of other 

 complex synthetic metabolites ; second, to add materially 

 to our knowledge of one of the most important substances 

 in the life-history of both plant and animal kingdoms; 

 and third, to throw open fields of investigation which 

 offer extraordinary promise, particularly in adding to our 

 knowledge of the all-important properties of protoplasm." 



Since the beginning of these researches, facts 

 have been accumulating steadily along various chan- 

 nels of investigation which are in support of the 

 propositions: That all vital phenomena are or will 

 be found "to be explicable upon a physico-chemical 

 basis ; that the line of demarcation between chemical 

 and biochemical laws and phenomena is fast disap- 

 pearing ; that it is becoming recognized that the 

 genesis of living matter, individuals, sex, varieties, 

 species, and genera is being resolved to studies of the 

 genesis of chemical compounds and interactions, and 

 of the laws and applications of physical chemistry; 

 and that the specificities of stereoisomerides in rela- 

 tion to various tissues, organs, and organisms is one 

 of the most extraordinary and fundamental phe- 

 nomena of living matter, and inseparable from 

 specificities of molecular constitutions and vital char- 

 acteristics of various forms of protoplasm. 



In the introduction of the Hemoglobin memoir 

 references were made to certain differences that have 

 been noted in corresponding substances, plant and 

 animal, in relation to biological classification ; and in 

 the corresponding chapter of the Starch memoir many 

 instances were cited of various substances, inorganic 

 and organic, that appear in stereoisomeric forms and 

 exhibit marked physical, nutritive, and toxic differ- 

 ences in accordance with peculiarities of molecular 

 configuration. Among such substances, those of bio- 



logic origin are of preeminent interest because of 

 their direct or indirect dependence upon protoplasm 

 for their existence and peculiarities, and many in- 

 vestigations bearing upon them have been carried 

 out (during especially the last decade) that are of 

 such particular importance in their bearings upon 

 the objects of these investigations as to demand here 

 at least casual notices. It has already been noted 

 that some years ago Hoppe-Seyler and others found 

 chat the pepsins of warm-blooded and cold-blooded 

 animals are not identical, and that Wroblewsky and 

 others recorded differences in the pepsins of differ- 

 ent animals. Now, it is of interest to note that these 

 differentiations have been added to by Hedin (Zeit. 

 f. physiolog. Chemie, 1911, LXXXII, 187; 1911, LXXIV, 

 242 ; 1912, LXXXII, 175), who found in comparative 

 studies of remduogens from species of different gen- 

 era that either renuase or antirenuase can be pre- 

 pared at will from the same renninogen, and that the 

 aiitireunase is inhibitory to the reunase of the same 

 species but not to the reimase of other species, there- 

 fore showing distinct generic specificity. Moreover, 

 it is probable, as Hediu pointed out, that the in- 

 vertases from different yeasts, bacteria, molds, etc., 

 are not identical. Scherman and Schlesinger (Proc. 

 Soc. Exp. Biol. and Med., 1915, xn, 118) have re- 

 ported that the amylases from pancreas and malt 

 are not identical. Malt amylase they found to be 

 most active in a somewhat acid solution, while the 

 optimum solution for pancreatic amylase is slightly 

 alkaline, and the amylase of pancreas was less than 

 half as active as that of malt. The investigations of 

 Dudley and Woodman (Biochem. Jour., 1915, ix, 

 97) indicate that the casein of sheep differs from 

 that of the cow ; and the studies by Dakin and Dudley 

 (Biochem. Jour., 1913, xv, 271) in digestion, 

 Schmidt (Proc. Soc. Exp. Biol. and Med., 1917, 

 xiv, 104) in immunization, Ten Broeck (Biolog. 

 Chem., 1914, xvn, 369) in antigenic tests, and 

 Underwood and Heudrix (Biolog. Chem., 1915, 

 xxn, 453) in toxicity experiments have shown that 

 ' racemic " casein is not identical with casein. 



The specificities of the hemoglobins and starches 

 in relation to the animal or plant source, as set forth 

 in the preceding memoirs, has had abundant support 

 by various biologic reactions (complement-fixation, 

 agglutinin, precipitin, anaphylactic). It seems evi- 

 dent that all of these reactions or tests have a bic- 

 chemic basis ; that they are dependent upon peculiari- 

 ties of chemical constitution or structure of protein 

 molecules ; and that they are " group " reactions in 

 the sense that they are restricted to the same or to 

 similar proteins of the same individual or closely 



