38 JOSHUA ROSETT 



here encountered are not to be considered as the same as those 

 called vital. Because a Traube's copper ferrocyanide cell 

 enlarges in much the same general manner as does a germinating 

 Vaucheria zoospore, this is not to be taken as evidence that the 

 zoospore with its resulting filament is composed of a copper 

 ferrocyanide membrane with a solution of copper salt on the 

 inside! It is clear that the chemical substances involved in 

 the living cells are entirely different from those of the artificial 

 model, and yet the latter does unquestionably serve to illustrate 

 some of the physico-chemical principles that are probably 

 effective in cell formation. 



Failure to emphasize this point in an adequate manner — the 

 point that artificial precipitation cells are like living ones only 

 with regard to the general nature of certain forces involved, 

 and to certain superficial characteristics of their mechanical 

 structure — seems to have been to blame for some features of 

 the present attitude of cytologists toward the study of these 

 artificial growths. Opposed on the one hand by the vitalists, 

 with their slogan of ignorabimus, as far as the molecular physics 

 and energetics of protoplasmic phenomena are concerned, and 

 on the other by the extreme mechanists, who are forever attempt- 

 ing the explanation of protoplasmic phenomena in terms that 

 are far too simple, the study of these interesting and suggestive 

 processes has had but few followers. They lie in a realm still 

 almost unentered either by physico-chemistry or by physiology. 

 Such writers as Leduc,^ for example, by emphasizing inordinatelj^ 

 the likenesses and ignoring the unlikenesses between the "won- 

 derful" phenomena of organic growth and the equally ' 'wonder- 

 ful" ones of physico-chemical growth, have done much to in- 

 culcate the current prejudice of biologists against this promis- 

 ing line of study. 



On the other hand, the dense ignorance of molecular physics 

 that still prevails among writers in experimental biology — the 



^ Leduc, S., Th6orie physico-chimique de la vie et generations spontanees. 

 English translation by W. Deane Butcher, entitled The mechanism of life. New 

 York, 1911. See also an article by W. Deane Butcher in Archives de Plasmologie 

 G^nerale, Brussels, 1912. 



