THE CELL DOOTKINB. 79 



Pringsheim had also shown, in 1,854, that no such 

 memhrane as a primordial utricle existed, hut that 

 all. within the cellulose wall of the living vegetable 

 cell was protoplasm and cell fluid, however complex 

 its composition. 



" He admitted that in the cortical layer of the pro- 

 toplasma a distinct arrangement into layers often 

 occurred, and these he distinguished as the cutaneous 

 and granular layers of the protoplasnia, but he de- 

 nied that the primordial utricle could be differen- 

 tiated as a membrane from the subjacent protoplasm. 

 If, in animal cells, partly from their relatively small 

 size, and partly from their greater average wealth in 

 protoplasraa, it is more rarely possible to make a 

 sharp demarcation between a cortical layer of pro- 

 toplasm and a cell fluid, there' nevertheless exists a 

 difference in the constitution of the former, such 

 that a cutaneous layer, destitute of or scantily sup- 

 plied with granules, incloses the remaining more 

 granular material. The white blood cell may serve 

 as an example. This is, however, very different, from 

 a proper membrane."* 



Ungerf (1855), had been struck with the close 

 similarity of the mobile phenomena of the Poly tha- 

 lamic with those of the processes of protoplasm 

 stretched across the. cavity of many vegetable cells. 

 Although he had not personally investigated the for- 

 mer, he became convinced from Schultze's description 

 that a resemblance amounting to identity existed 



* Duffin, A. B., On Protoplasm. Quart. Jour. Mio. Soi., N. 

 S., vol. iil, 1863, p. 252. 

 + Unger, op. cital., p. 280. 



