722 THE POPULAR SCIENCE MONTHLY. 



new generations by fission, and abdicate their individuality in favor 

 of a greater or less number of new individualities. It is also to be 

 seen in those organisms on whose surface a new organism is formed 

 by the process of budding. Here the disintegration is perfect, or 

 nearly so, but in the higher organisms the disintegration affects only 

 an insignificant portion of the parent. 



Why this special disintegration ? Biology can give no answer, 

 unless we suppose that the genesis of individuals belongs as a genus to 

 a class of facts including all the phenomena of general disintegration 

 which attend growth, and which mark the gradual decline of the or- 

 ganism. This supposition finds its wai'rant in the fact that, as a 

 general rule, reproduction does not take place until growth and struct- 

 ural development approach their term, when the molecular forces of 

 the physiological units find themselves in equilibrium with the forces 

 of the orojanism as a whole, and with the foi-ces from without. Disin- 

 tegration would now set in, or, to speak more exactly, disintegration 

 would now begin to show an excess over integration, for, ever since 

 the earliest vital phenomenon, disintegration has constantly accom- 

 panied integration. Among the various modes in which the decline 

 of the organism is gradually brought about, there is one which re- 

 sembles all the others, inasmuch as it constitutes a loss to the indi- 

 vidual, but which differs from them in that it gives rise to new organ- 

 isms. In a large number of cases among individuals of the lower 

 orders of organisms, units combined in a certain group, and carrying 

 away with them, as we have seen, their own proper tendency to find 

 the equilibrium of their forces in arrangements similar to those in 

 which they were originally integrated, become detached, and form 

 the centre of a new integration. But in a very large number of or- 

 ganisms, and in all higher organisms of both the organic kingdoms, 

 reproduction takes place by the mixture of two products, the one 

 germinal, the other spermatic, coming from slightly different physio- 

 logical units. In virtue of a property found in the simplest organic 

 elements, and still more markedly present in the complex organic ele- 

 ments of living things, the mixture of substances which differ little 

 from one another gives rise to products that are less stable than their 

 constituent elements. Accordingly, the result of this mixture, name- 

 ly, the fecundated germ, is farther fi-om the state of equilibrium than 

 wei'e the units emitted by each of the parents, in the shape of germi- 

 nal and spermatic cells. The faint tendency which existed in each 

 of these groups to produce evolutional phenomena is intensified with 

 the instability of the mixture. From this we may infer, if not the 

 impossibility, at least the difficulty of an agamic genesis, and the 

 necessity of a genesis by concurrence of different sexes. This con- 

 clusion, derived from the law of equilibrium, which itself flows from 

 the law of persistence of force, seems to be hardly in agreement with 

 facts, since unquestionably there exists such a thing as agamic gene- 



