Febkuaby 14, 1908] 



SCIENCE 



253 



convincing. However, this is not the time 

 to enter into detailed discussion regarding 

 such questions, as the chemical evidence is 

 altogether unsatisfactory and fragmentary. 

 "We must rest content at present with the 

 few suggestions already put forward, 

 understanding that our object at this mo- 

 ment is merely) to emphasize the need of 

 broader and more exact knowledge in a 

 field of investigation where chemical 

 processes are undoubtedly of paramount 

 importance. The problems involved are 

 many, and future advance is to be looked 

 for from chemists as well as from workers 

 in the fields of morphology and cytology. 



Students of heredity are inclined to be- 

 lieve, on the basis of Mendel's experiments 

 on hybridization, etc., that each individual 

 characteristic of a species is represented 

 by a definite determinant in the germ cell. 

 As Loeb has expressed it, "this determi- 

 nant may be a definite chemical compound. 

 The transition or mutation from one form 

 into another is therefore only possible 

 through the addition or disappearance of 

 one or more of the characteristics or de- 

 terminants." Look where we will and 

 such suggestions as these are ever before 

 us. We may recognize to the fullest degree 

 the value of the work which has been done, 

 and is still being carried forward so suc- 

 cessfully, on the chemical dynamics of 

 physiological processes and the important 

 bearing which the results thereby obtained 

 have upon the problems we are now dis- 

 cussing, yet there is still before us the un- 

 answered question what are these specific 

 determinants that are the carriers of 

 heredity? If their individuality is bound 

 up, as may well be believed, in the chemical 

 structure of the protoplasm, what is the 

 nature of the gi-oups involved? What the 

 character of the ions that are instrumental 

 hy their presence or absence in determining 

 processes that are so fundamental in the 

 perpetuation of species or in the produc- 



tion of modifications? Biological chemists 

 may well work with enthusiasm on such a 

 subject, and while it may be that one 

 person's thoughts, for example, will lead 

 him to a study of organic structure, 

 another may be led with equal force to in- 

 vestigate the influence of positive and 

 negative electrons on protoplasmic ac- 

 tivity, each equally impressed with the 

 value of his work in its possible bearing on 

 the solution of the problem. Indeed, 

 there is, I think, perfect assurance that 

 both lines of work are called for if there is 

 to be found positive answers for the many 

 questions constantly arising relative to the 

 subject of heredity and the transmission of 

 specific characteristics. The problem is 

 indeed intricate, or so appears at present, 

 and we can only hope for success by fol- 

 lowing up every line of approach that 

 presents itself. 



The topics on which I have ventured to 

 touch in this brief presentation are a small 

 fraction only of those which will arise in 

 the minds of most biological chemists in 

 thinking of our present-day problems. 

 The number is indeed legion. Problems 

 of many kinds confront us of varying de- 

 grees of importance, and on their solution 

 depends our rate of progress. The spirit 

 of investigation is abroad and it is our 

 duty, as it should be our pleasure, to ex- 

 hibit all possible zeal in advancing knowl- 

 edge of bio-chemical processes. Oppor- 

 tunities in this country have greatly 

 increased of late. The time was, and only 

 a few years ago, when it was a rarity to 

 find a laboratory of physiological chem- 

 istry attached to a university. Now, such 

 laboratories are to be seen on all sides, and 

 men of power are being trained to carry 

 on investigation in this attractive and 

 promising field of work. Further, the 

 great research institutions recently estab- 

 lished. The Carnegie Institution of Wash- 

 ington, The Rockefeller Institute for 



