CONFORMITY TO TYPE 253 



and aggregate themselves into buds and the sexual elements; 

 their development depending on their union with other nascent 

 cells or units. They are also believed to be capable of trans- 

 mission in a dormant state, like seeds in the ground, to successive 

 generations." 



"In a highly organized animal, the gemmules thrown off from 

 each different unit throughout the body must be inconceivably 

 numerous and minute. Each unit of each part, as it changes 

 during development, and we know that some insects undergo at 

 least twenty metamorphoses, must throw off its gemmules. But 

 the same cells may long continue to increase by self-division, and 

 even become modified by absorbing peculiar nutriment, without 

 necessarily throwing off modified gemmules." 



" All organic beings, moreover, include many dormant gemmules 

 derived from their grandparents and more remote progenitors, 

 but not from all their progenitors. These almost infinitely numer- 

 ous and minute gemmules are contained within each bud, ovule, 

 spermatozoon, and pollen grain. Such an admission will be 

 declared impossible; but number and size are only relative diffi- 

 culties. Independent organisms exist which are barely visible 

 under the highest powers of the microscope, and their germs must 

 be exceedingly minute. Particles of infectious matter, so small 

 as to be wafted by the wind or to adhere to smooth paper, will 

 multiply so rapidly as to infect within a short time the whole body 

 of a large animal. We should also reflect on the admitted number 

 and minuteness of the molecules composing a particle of ordinary 

 matter. The difficulty, therefore, which at first appears insur- 

 mountable, of believing in the existence of gemmules so numerous 

 and so small as they must be according to our hypothesis has no 

 great weight. The units of the body are generally admitted by 

 physiologists to be autonomous. 



"I go one step further and assume that they throw off repro- 

 ductive gemmules. 



"Thus an organism does not generate its kind as a whole, but 

 each separate unit generates its kind. It has often been said by 

 naturalists that each cell of a plant has the potential capacity 

 of reproducing the whole plant; but it has this power only in 

 virtue of containing gemmules derived from every part. When a 

 cell or unit is from some cause modified, the gemmules derived 

 from it will be in like manner modified. 



" If our hypothesis be provisionally accepted, we must look at all 

 the forms of asexual reproduction, whether occurring at maturity 

 or during youth, as fundamentally the same and dependent on 

 the mutual aggregation and multiplication of the gemmules. 

 The regrowth of an amputated limb and the healing of a wound is 

 the same process partially carried out. Buds apparently include 

 nascent cells, belonging to that stage of development at which 

 the budding occurs, and the cells are ready to unite with the 

 gemmules derived from the next succeeding cells. 



"The sexual elements, on the other hand, do not include such 

 nascent cells; and the male and female elements taken separately 

 do not contain a sufficient number of gemmules for independent 

 development, except in the cases of parthenogenesis. 



