2 Ernst Schuhe [Sept. 



tein metabolism, as they were stated by Voit on the basis of experi- 

 ments on carnivorous animals, applied to the ruminants as well. 

 In Zürich, Schulze brought his researches in animal physiology to 

 an end by a thorough investigation of wool-fat. He succeeded in 

 preparing typical cholesterol in a pure State and in isolating an 

 isomer, isocholesterol. 



Since 1872 Schulze had concerned himself exclusively with phy- 

 tochemical research ; and forty years of activity in this field f ortified 

 the conclusion that plants and animals contain the same classes of 

 substances and that the chemical composition of animals is in many 

 ways identical with that of plants. 



Schulze developed new methods for the quantitative determina- 

 tion of nitrogenous substances and showed how to separate them in 

 pure forms from the complex mixtures in plant Juices and extracts. 

 With his collaborators Schulze made classical discoveries of the fol- 

 lowing nitrogenous Compounds and, by masterly methods, estab- 

 lished their Constitution : 



Glutamin, an amide of glutamic acid ; 



Arginin, guanido-ot-aminovalerianic acid ; 



Phenylalanin, yS-phenyl-ct-aminopropionic acid ; 



Vernin (identical with the guanosin subsequently obtained by 

 Levene from nucleic acid) ; 



Stachydrin, the dimethylbetain of a-prolin ; 



Lupinin, an alkaloid from lupins. 



Schulze found the following nitrogenous substances in different 

 plant materials and studied their role in plant metabolism: amino- 

 valerianic acid, leucin, isoleucin, prolin, glutamin, asparagin, Phenyl- 

 alanin, tyrosin, arginin, histidin, lysin, vicin, convicin, xanthin, hy- 

 poxanthin, guanidin, vernin, allantoin, cholin, betain, trigonellin, 

 and stachydrin. Schulze was working with the betains during his 

 last illness but, unfortunately, he was unable to complete this re- 

 search. Considerable interest was aroused by his discoveiy of the 

 presence of allantoin in plants. 



Schulze was the first to make a successful investigation of phyto- 

 lecithins ( Phosphatids) and their cleavage products. He found 

 that the lecithin in many seeds can be extracted only with hoiling 

 alcohol. For this reason he believed that lecithin exists in such 



