30 



THE CELL 



beyond a doubt the identity of sarcode with the protoplasm of plant and animal 

 cells ; and this discovery was most helpful to Max Schultze in working out his 



cell theory, and in estab- 

 lishing his theory of pro- 

 toplasm (p. 6). 



In Amoeba, lymph 

 cells, Mycetozoa, and 

 Keticularia, we have 

 learnt to recognise 

 naked cells ; those of 

 plants on the contrary 

 are almost invariably 

 enclosed by a well- 

 defined layer, which is 

 sometimes very thick 

 and firm; this is also 

 very frequently the 

 case with animal cells 

 (membrane, intercel- 

 lular substance), and 

 thus in such cases a 

 little chamber, or cell, 

 in the true sense of 

 the word is formed. 

 Young cells from the 

 neighbourhood of the 

 growing point of a 

 plant, and cartilage 

 cells from a Salaman- 

 der larva, are very 

 good examples of this. 



The cells at the 

 growing point of a 

 plant (Fig. 12^1), 

 where they multiply 

 very rapidly, are very 

 small, and are very 

 similar to animal 

 cells. They are only 

 separated from one 



Fig. lO.-Gromia oviformis. (After M. Schultze.) another by very thin 





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