PART II 



GENEEAL PAET 



ALTHOUGH I have devoted much time to the study of the 

 numerous works upon the structural relations of protoplasm, 

 it seemed to me at first, after much reflection, almost advisable 

 not to enter into a critical and historical examination of the 

 subject, but to simply communicate my observations and 

 the conclusions drawn from them. On the one hand, this 

 subject has already frequently been treated in great detail 

 from the point of view of its gradual development; on the 

 other hand, I am somewhat doubtful as to the value of 

 detailed expositions of this kind, especially in a question 

 which is as yet so little ripe for final treatment ; besides 

 which, the great productiveness of the present time puts 

 every one's power of assimilation to a severe test, so that 

 brevity appears to be the ideal to be striven after. 



Nevertheless, even at the risk of not being read, I 

 made up my mind, after all, to give a compressed summary 

 of the gradual development of the structural question. I 

 have, as already stated, worked conscientiously through the 

 works accessible to me, so far as I was able, without, how- 

 ever, wishing to set up any claim to completeness ; this is, 

 as a matter of fact, scarcely possible, especially for more 

 recent times, in which such floods of literature have been 

 poured out dealing with the subject. Since, moreover, we 

 are in no way concerned with reporting carefully upon 

 every single work in which anything is said concerning the 



