ANATOMY AND PHYSIOLOGY 



isms, as the blood corpuscles. Particularly in the case 

 of cells that change their shape markedly, moving 

 about in consequence of the streaming of their sarcode, 

 did it seem certain that no cell wall is present, or that, 

 if present, its role must be insignificant. 



And so histologists came to question whether, after 

 all, the cell contents rather than the enclosing wall must 

 not be the really essential structure, and the weight of 

 increasing observations finally left no escape from the 

 conclusion that such is really the case. But attention 

 being thus focalized on the cell contents, it was at once 

 apparent that there is a far closer similarity between 

 the ultimate particles of vegetables and those of ani- 

 mals than had been supposed. Cellulose and animal 

 membrane being now regarded as mere by-products, 

 the way was clear for the recognition of the fact that 

 vegetable protoplasm and animal sarcode are marvel- 

 lously similar in appearance and general properties. 

 The closer the observation the more striking seemed 

 this similarity; and finally, about 1860, it was demon- 

 strated by Heinrich de Bary and by Max Schultze that 

 the two are to all intents and purposes identical. Even 

 earlier Remak had reached a similar conclusion, and 

 applied Von Mohl's word protoplasm to animal cell 

 contents, and now this application soon became uni- 

 versal. Thenceforth this protoplasm was to assume 

 the utmost importance in the physiological world, be- 

 ing recognized as the universal " physical basis of life," 

 vegetable and animal alike. This amounted to the 

 logical extension and culmination of Schwann's doc- 

 trine as to the similarity of development of the two ani- 

 mate kingdoms. Yet at the same time it was in effect 



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