The Orcjfinititn find its Chcnitstrtj 107 



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

 of some particular species, or possibly variety, or even 

 individual. 



A. P. Mathcws, 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 starfish Axterias forbexii. 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 

 Mat hews 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 Comparative 



Chemistry* 



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

 chemist ry are being inevitably drawn together by the very 



* Since this chapter was written J. Loeb's The Organism as a Whole 

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

 the author is being carried, as it seems to me, unconsciously perhaps, 

 toward the organi.Miial and natural history standpoint. One piece of 

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

 Loeb gives us a chapter with the title The Cficniirnl />'</.v/,v of Gfeivus and 

 S/xrit.f. 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 

 lie 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. T/K' clu'inixt /.s- follniriiKj the iialnrnHst and 

 ri'fitihif/ /hi' hiltcr'n nirl1nnl$ in i-frlain parti&tlttfi Ix-tjund din/thin;/ he 

 liiin.fi'lf ix ciifnililc 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- 



