DARWIN. Ill 



of evolution, lie hidden in every organic being. "The 

 fertilised germ of one of the higher animals, subjected 

 as it is to so vast a series of changes from the germinal 

 cell to old age incessantly agitated by what Quatrefages 

 well calls the tourbillon vital is perhaps the most 

 wonderful object in nature. It is probable that hardly a 

 change of any kind affects either parent, without some 

 mark being left on the germ. But on the doctrine of 

 reversion the germ becomes a far more marvellous 

 object, for, besides the visible changes to which it is 

 subjected, we must believe that it is crowded with 

 invisible characters, proper to both sexes, to both the 

 right and left side of the body, and to a long line of male 

 and female ancestors separated by hundreds or even 

 thousands of generations from the present time ; and 

 these characters, like those written on paper with invisible 

 ink, all lie ready to be evolved under certain known or 

 unknown conditions." 



Through a further discussion of many deeply interesting 

 facts about the intercrossing of breeds and species, and 

 about the causes of variability, we pass to the hypothesis 

 of pangenesis, which, briefly stated, supposes that the 

 cells or units of the body are perpetually throwing off 

 minute granules or gemmules, which accumulate in the 

 reproductive system, and may, instead of developing in 

 the next generation, be transmitted in a dormant state 

 through more than one generation and then be developed. 

 Combination in various degrees between these gemmules 

 is supposed to influence their appearance or non-appear- 

 ance in the offspring at various stages. 



This hypothesis certainly gives a picture of a possible 



