280 THE INDUCTIONS OF BIOLOGY. 



a group from another part of it. Yet self-fertilization does 

 occur. Though the ovules of one plant, are generally fer- 

 tilized by pollen from another plant of the same kind ; yet 

 they may be, some of them, fertilized by the pollen of the same 

 plant. And though, among hermaphrodite animals, self-fer- 

 tilization is usually negatived by structural or functional ar- 

 rangements ; yet in certain Entozoa, there appear to be special 

 provisions by which the sperm-cells and germ-cells of the same 

 individual may be united, when not previously united with 

 those of another individual. Certainly, at first sight, these 

 facts do not consist with the above supposition. Neverthe- 

 less, there is a satisfactory solution of them. 



In the last chapter, when considering the variations that 

 may result in offspring from the combination of unlike 

 parental constitutions, it was pointed out that in an unfolding 

 organism, composed of slightly-different physiological units 

 derived from slightly- different parents, there cannot be main- 

 tained an even distribution of the two orders of units. We 

 saw that the instability of the homogeneous, negatives the 

 uniform blending of them ; and that, by the process of differ- 

 entiation and integration, they must be more or less separated ; 

 so that in one part of the body the influence of one parent will 

 predominate, and in another part of the body the influence of 

 the other parent : an inference which harmonizes with daily 

 observation. And we also saw, that the sperm-cells or germ- 

 cells produced by such an organism, must, in virtue of these 

 same laws, be more or less unlike one another. It was shown 

 that through segregation, some of the sperm-cells or germ- 

 cells will get an excess of the physiological units derived 

 from one side, and some of them an excess of those derived 

 from the other side : a cause which accounts for the unlikenesses 

 among offspring simultaneously produced. ISTow from this 

 segregation of the different orders of physiological units, in- 

 herited from different parents and lines of ancestor, there 

 arises the possibility of self-fertilization, in hermaphrodite 

 organisms. If the physiological units contained in the sperm* 



