30 



THE CELL 



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

 cells ; anl 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 

 Reticularia, 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 A), 

 where they multiply 

 very rapidly, are very 

 small, and are very 

 similar to animal 

 cells. They are only 

 separated from one 

 another by very thin 



FIG. 10. Gromta omformis. (After M. Schultze.) 



