The Organism and Its Cliemistrij 83 



substances of simple constitution is of profound biological 

 significance. Apart from its biological bearings as the sim- 

 plest type of immunity reaction, it throws vivid light, and 

 its further study must throw fresh light, on the potentiali- 

 ties of the tissue laboratories." 8 



Different Organisms as Different Chemical Laboratories 



But this glance in the exclusively descriptive way, at the 

 chemical foundations of the organism in the various stages 

 of its life, in no wise satisfies the modern natural history 

 standpoint. As indicated in the remarks introductory to 

 this chapter, that standpoint is comparative as essentially 

 as it is descriptive. The moment this methodological plank 

 in the natural historian's platform is reached, the insuffi- 

 ciency is seen of the conclusion that some individual organ- 

 isms are * manufacturing chemists or even that all are. 

 Taken thus the result is altogether too general. The most 

 cursory observation leads to the recognition that if every 

 organism be a producer of chemical substances, not all 

 organisms can be producers of the same substances, and 

 that the extent and nature of the diversity of products 

 would be interesting and important from both scientific and 

 practical considerations. Now the comparative method in 

 /oology has its roots in the every day knowledge that ani- 

 mals and plants are to some extent different from one 

 another. Applying this method consistently and with suffi- 

 cient rigor for the present inquiry, the problem formulates 

 itself as follows : How far do the readily observable re- 

 semblances and differences between organisms reach down 

 into their chemical make-up? Does the present state of 

 advancement of biochemistry warrant the supposition that 

 for every well-established similarity and for every well-es- 

 tablished difference between organisms, both as to individuals 

 and species and as to structure and function, there is a 

 corresponding chemical similarity and difference? 



