The Orgnmsm and its Chemisfr?/ 107 



upon as just trypsin, but must be regarded as the trypsin 

 of some particular species, or possibly variety, or even 

 individual. 



A. P. Mathews, more regardful of the source of his scien- 

 tific blessings, that is, of the material on which he works, 

 as well as of other essentials, is explicit and informs us that 

 the eggs of the sea-urchin Arbacea punctulata, differ 

 markedly in their physiological properties from those of 

 the stai*fish Asterias forbesii. The differences in "physi- 

 ological properties" noticed consist in the greater stability 

 of the sea-urchin egg as manifest in its resistance to oxida- 

 tion, low rate of respiration, and relative insensibility to 

 stimuli inducing artificial parthenogenesis. These differences 

 Mathews finds to be correlated with the possession by the 

 sea-urchin egg of considerable quantities of the widespread 

 substance cholesterol, and the absence either wholly or in 

 part, of that substance in the starfish egg. 



The Coalescence of Natural History and Comj)cirative 



Chemistry* 



It seems then from all this that natural history and bio- 

 chemistry are being inevitably drawn together by the very 



* Since this chapter was written J. Loeb's The Orc/anism as a Whole 

 has been published. It is gratifying to find in this book evidence that 

 the author is being carried, as it seems to me, unconsciouslj'^ perhaps, 

 toward the organismal and natural history standpoint. One piece of 

 such evidence may Ije appropriately noticed at this point. It is that 

 I.oeb gives us a chapter with the title The Chemical Basis of Geims and 

 Species. This seems to show that now, since specificity is coming down 

 to a chemical basis, taxonomy is assuming a reality and significance in 

 this author's mind which it did not have formerly. But attention should 

 be called to the fact that knowledge of the chemical differentiation of 

 taxonomic categories has not made their reality one whit more posi- 

 tive than it was before. The chemist is following the naturalist and 

 refininy the latter's methods in certain particulars beyond anything he 

 himself is capable of. "In certain particulars," I say, because in certain 

 other particulars the naturalist is still far in advance of the chemist. 

 Thus the naturalist knows beyond a trace of uncertainty innumerable 

 "specific differences" among plants and animals which the chemist, as 

 a chemist, can not yet so much as touch. In fact, the lack of compre- 



