1 882.] Organic Physics. 561 



though perhaps the more vigorous assimilative energy at that 

 period of life may render both the coherent and the free cell 

 formation very active. In mature life the cessation of growth 

 seems to indicate a loss of the coherent energy. The great mass 

 of the new cells are perhaps budded out as free individuals into 

 the lymph, while only enough remain coherent to keep up the 

 integrity of the tissues. In old age even this fails, and the body 

 shrinks. It is becoming disintegrated by the growing pieponder- 

 ance of free over coherent cell formation. It is not improbable 

 that the increasing thickness and density of the tissues may have 

 some influence upon this result. Nutriment reaches them less 

 readily, and the new cells are more advantageously situated in 

 the free than in the coherent state. 



Thus the independent life of the cells becomes, as life goes on, 

 less and less subordinated to the needs of the body. Each cohe- 

 rent cell buds off minute gemmules, or organic units, which 

 quickly assimilate nutriment from the rich plasma surrounding 

 them, and grow into amoeboid cells. These buds may be, in 

 many cases, very minute, for corpuscles will arise in an apparently 

 homogeneous blastema. Some writers argue that this blastema 

 is structureless, but it is not easy to credit that it is destitute of 

 the germs of organized structure. These may be excessively 

 minute masses of molecules, invisible gemmules derived from the 

 tissues, but they must be present as centers and controlling agents 

 of the organized corpuscles which quickly appear. We are, 

 therefore, forced to believe that the colony of coherent cells which 

 forms the body as a whole, gives rise to a colony of free individ- 

 uals, which swim off and develop in the surrounding fluid, pre- 

 cisely as the budded offspring of a lowly organized animal float 

 away to develop as independent individuals. The body continues 

 to absorb nutriment, but the products of its nutrition flow away 



0r ganisms. Cessation of individual !itbbecomJs necessary from 

 the ^creasing tendency of the body to resolve itself into its 



If n«> w we hastily review the process of reproduction through- 

 out the range of animal life, we shall find it to favor the hypothe- 

 cs here proposed. Everywhere there seems a struggle between 

 the opposite tendencies of new germs to remain coherent and to 

 become independent. The result undoubtedly strictly depends 



