33^ llc'uiricli RittJuuiscii [April 



neutral sah snliuiun and were nnaltered in elcnienlar\- cumposition. 

 Linie attention was, howex-er. paid \n this later work, although bis 

 pa])ers were filled witli int'orniatiun that has proxed morc helpful 

 in de\"el()i)ing" nur present knowledge of the ehemistrv uf proteins 

 in general than has mosl of that ftn'nished l)\' bis critics. 



Aniong the many proteins which he acenralely described were 

 several that could easily be obtained in well-formed crystals, a fact 

 which. at that tinie. was of great importance in i)rotein chemistry. 

 Thns. in 1881, he described a crystalline protein of the hemp-seed 

 and the method for its preparation, which is essentially that now in 

 nse. For more than twenty years this protein remained almost 

 unknown although in recent years, under the name of edestin, it 

 has been employed in hundreds of i)hysiological experiments in con- 

 nection with a great variety of problems in protein chemistry. As 

 a result of bis later w^rk he proved that wide difTerences exist 

 between different food proteins; and he was the first to direct at- 

 tention to this fact, and to discuss its probable bearing on their 

 relative value in nutrition. 



Ritthausen's studies were not confined solely to the \-egetable 

 proteins, as is evident from bis extensive bibliography which ap- 

 pears at page 339. He made man}- im-estigations of other con- 

 stituents of seeds. obtaining \icin and convicin from vetch seeds, 

 and discovered in the cotton-seed " melitose " now known as 

 raffinose. 



If we are to judge Ritthausen's work fairly we must remember 

 that it was begun under the influence of Liebig's erroneous assump- 

 tion that only a few forms of protein existed ; that at that time 

 organic chemistr}- was in its infanc}-; that few methods were known 

 by which jjroteins could be isolated from the tissues containing them, 

 or by which the different proteins could be separated from one 

 another and be purified : that the only means for preventing the 

 changes caused by bacteria and enzymes were low temperatures ; 

 and that the facilities for conducting such investigations were very 

 limited. "Ko the writer, who has had a long experience in this same 

 field. under the vastly more favorable conditions pre\'ailing a gen- 

 eration later, it is astonishing that Ritthausen accomplished so much, 

 and that the data he secured were in the main so accurate. What- 



