70 BEALE'S PROTOPLASMIC THEORY. 



may become old, hardened, and cracked. If the cell 

 is destined to be cast off and perish, the bioplasm in 

 the inside is gradually consumed by its conversion 

 into formed material, and is not renewed from pa- 

 bulum. The epidermic and some other cells of the 

 higher animals are in this case. But when the func- 

 tion of the bioplast is to be continued, its substance is 

 renewed from the nutrient fluid which passes through 

 the cell wall, or other formed material correspond! ng 

 to it. On this plan, the nutrition of cells of epithelium 

 and other bioplasts of man is conducted (197). On 

 this principle substantially, in fact, all growth and 

 nutrition are conducted. When increase or multiplica- 

 tion of cells, or any other formed material, takes place, 

 it is always the bioplasm alone which grows, divides, 

 and sub-divides, and becomes surrounded by formed 

 material produced by it. The formed material is 

 always passive, and takes no part in this process, and 

 never of itself grows in, or moves in, and forms par- 

 titions. The process of subdivision of the protoplasm 

 is easy to be seen. It is shown, among others, in pi. 

 vi. of Beale's " Protoplasm," third edition. When no 

 new growth is going on, no further subdivisions take 

 place, and the consumption of protoplasm and assimila- 

 tion of pabulum remain balanced. But gradually, as 

 age advances, the consumption of protoplasm exceeds 

 the renewal, and in proportion the formed material 

 exceeds the biopla&m in quantity, so that, at least in 

 some tissues, the latter amounts only to l-100th part. 



With respect to the intimate nature of the process 

 of nutrition, it may be said to be co-extensive with 

 life itself, and the whole " investigation of it may be 



