IV PREFACE. 



"In accordance with the foregoing statement, it can readily be understood how environ- 

 ment, for instance, might so affect the individual's metaboHc processes as to give rise to 

 modifications of the constitutions of certain corresponding proteins and other vital mole- 

 cules which, even though they be of too subtle a character for the chemist to detect by his 

 present methods, may nevertheless be sufficient to cause not only physiological and mor- 

 phological differentiations in the individual, but also become manifested physiologically 

 and morphologically in the offspring. 



"Furthermore, if the corresponding proteins and other complex organic structural 

 units of the different forms of protoplasm are not identical in chemical constitution, it 

 would seem to follow, as a corollary, that the homologous organic metabolites should have 

 specific dependent differences. If this be so, it is obvious that such differences should 

 constitute a preeminently important means of determining the structural and physio- 

 logical peculiarities of protoplasm. 



"It was such germinal thoughts that led to the present research, which I began upon 

 the hypothesis that if it should be found that corresponding vital substances are not 

 identical, the alterations in one would doubtless be associated with related changes in 

 others, and that if definite relationships could be shown to exist between these differences 

 and peculiarities of the living organism, a fundamental principle of the utmost importance 

 would be established in the explanation of heredity, mutations, the influences of food and 

 environment, the differentiation of sex, and other great problems of biology, normal and 

 pathological. 



"To what extent this hypothesis is well founded may be judged from this partial 

 report of the results of our investigations: It has been conclusively shown not only that 

 corresponding hemoglobins are not identical, but also that their peculiarities are of posi- 

 tive generic specificity, and even much more sensitive in their differentiations than the 

 ' zooprecipitin test.' Moreover, it has been found that one can with some certainty pre- 

 dict by these peculiarities, without pre^ious knowledge of the species from which the hemo- 

 globins were derived, whether or not interbreeding is probable or possible, and also certain 

 characteristics of habit, etc., as will lie seen by the context. The question of interbreeding 

 has, for instance, seemed perfectly clear in the case of Canida and Muridce, and no difficulty 

 was experienced in forecasting similarities and dissimilarities of habit in Sciuridce, MuridxB, 

 Fdidcc, etc., not because hemoglobin is -per se the determining factor, but because, accord- 

 ing to this hypothesis, it serves as an index (gross though it be, with our present very 

 limited knowledge) of those physico-chemical properties which serve directly or indkectly 

 to differentiate genera, species, and individuals. In other words, vital peculiarities may 

 be resolved to a physico-chemical basis." 



Before and since the inception of the foregoing research, data have been slowly 

 accumulating which point more and more strongly to the extremely important 

 interrelationships that exist between the intramolecular configurations of various 

 substances that play active roles in life's processes and the configurations of pro- 

 toplasm. Hence, any progress in the application of stereochemistry to metabolic 

 processes brings us closer to an understanding of those peculiar mechanisms of 

 protoplasm which give rise to the phenomena which in the aggregate constitute 

 life in its normal and abnormal manifestations. 



Hemoglobin, next to protoplasm, is unquestionably the most important organic 

 substance of vertebrate life, and in conjunction with the stroma with which it is 

 associated is an active functionating protein, the main function of which is the 

 conveyance of oxygen from the external organs of respiration to the internal organs 

 of respiration or the tissues generally. Starch is similarly an extremely important 



