22 PROTOPLASM. 



debris of living organisms which have passed away. Nu- 

 merous minute living forms are, however, still found on it. 



Dr. Wallich is of opinion that each coccosphere is just 

 as much an independent structure at Thalassicolla or Col- 

 losphcera, and that, as in other cases, " nutrition is effected 

 by a vital act," which enables the organism to extract from 

 the surrounding medium the elements adapted for its nutri- 

 tion. These are at length converted into its sarcode and 

 shell material. In fact, in these lowest simplest forms, we 

 find evidence of the working of an inherent vital power, and 

 in them nutrition seems to be conducted upon the same 

 principles as in the highest and most complex beings. In 

 all cases the process involves, besides physical and chemical 

 changes, purely vital actions, which cannot be imitated, and 

 which cannot be explained by Physics and Chemistry. 



Chemistry of Protoplasm. 



From what has been said already, it must be obvious 

 that the chemistry of the complex matter now termed pro- 

 toplasm, embraces, i, the chemistry of the formed matter, 

 and 2, the chemistry of the active, living, growing, matter, 

 of the organism. By chemical analysis we can ascertain the 

 composition of the first, and can learn many facts con- 

 cerning its elementary chemical characters ; but it is obvious 

 that chemistry can teach us little with regard to the com- 

 position of the living matter, for we kill it when we attempt 

 to analyze it ; and in truth we analyze not the living matter, 

 but the substances resulting from its death. Of course any 

 one may say that the inanimate substances he obtains were 

 the actual things of which the living matter was composed, 



