Chap. XXYII. OF PANGENESIS. 361 



of perfectly characterised lemon-peel. With peas, several 

 observers have seen the colour of the seed-coats and even 

 of the pod directly affected by the pollen of a distinct 

 variety. So it has been with the fruit of the apple, which 

 consists of the modified calyx and upper part of the flower- 

 stalk. In ordinary cases these parts are wholly formed by 

 the mother-plant. We here see that the formative elements 

 included within the male element or pollen of one variety 

 can affect and hybridise, not the part which they are properly 

 adapted to affect, namely, the ovules, but the partially-developed 

 tissues of a distinct variety or species. We are thus brought 

 half-way towards a graft-hybrid, in which the formative 

 elements included within the tissues of one individual com- 

 bine with those included in the tissues of a distinct variety 

 or species, thus giving rise to a new and intermediate form, 

 independently of the male or female sexual organs. 



With, animals which do not breed until nearly mature, and 

 of which all the parts are then fully developed, it is hardly 

 possible that the male element should directly affect the 

 female. But we have the analogous and perfectly well-ascer- 

 tained case of the male element affecting (as with the 

 cjuagga and Lord Morton's mare) the female or her ova, in 

 such a manner that when she is impregnated by another 

 male her offspring are affected and hybridised by the first 

 male. The explanation would be simple if the spermatozoa 

 could keep alive within the body of the female during the 

 long interval which has sometimes elapsed between the two 

 acts of impregnation; but no one will suppose that this is 

 possible with the higher animals. 



Development. — The fertilised germ reaches maturity by a 

 vast number of changes : these are either slight and slowly 

 effected, as when the child grows into the man, or are great 

 and sudden, as with the metamorphoses of most insects. 

 Between these extremes we have every gradation, even within 

 the same class; thus, as Sir J. Lubbock has shown, 28 there 

 is an Ephemerous insect which moults above twenty times, 

 undergoing each time a slight but decided change of structure ; 

 and these changes, as he further remarks, probably reveal to 



28 ' Transact. Linn. Soc.,' vol. xxiv., 1863, p. 62. 



