BECAPITULATION 111 



offspring recapitulates the life-history of its immediate 

 parents from the time it is a single cell until it reaches 

 adult life, but the recapitulation is always associated with 

 variations in detail. These variations are very small in 

 comparison to the points of similarity, but still the recapitu- 

 lation is of the life-history of the parents with variations. 



In plants growing from buds, cuttings, and runners, 

 recapitulation is avoided, but otherwise it is a phenomenon 

 common to all multicellular organisms. Going back to 

 man, it is evident that, as the new individual has always 

 recapitulated the orderly succession of steps in development 

 that were passed through by its parents, the ancestors of 

 man must have also recapitulated the development of their 

 parents, so that in different stages in the production of a 

 man, the life-history of the development of the race from 

 more primitive forms should theoretically be reproduced 

 in every individual. This is true to some extent, but there 

 is another point which must be borne in mind. Variations 

 occur in every stage of the development. 



As evolution of the race proceeds, the environment of the 

 individual during its development must change at every 

 progressive step. The remote ancestors of man were appa- 

 rently at one time aquatic animals. The human embryo 

 passes through a stage where the arrangement of the large 

 blood vessels is similar to that which supplies the blood 

 to the gills of fishes. But at a very remote period the 

 power of absorbing free oxygen from water must have 

 become useless. The embryo within the uterus could gain 

 no advantage from the possession of gills, and this stage 

 has been so far eliminated that there is but a shadowy 

 representation of it. The same is true with regard to a 

 great many other stages in the development of the human 

 embryo. 



Now many of these variations are regressive, and it will 

 be readily realised that unless these regressive variations 

 had occurred, not only during the later stages but at every 

 step in the development of the individual, the production 



