Sect. XXXIX. 5. 2. GENERATION. 403 



coloured. And thus, like the fable of the chameleon, all ani- 

 mals may poffefs a tendency to be coloured fomewhat like the 

 colours they molt frequently infpect, and finally, that colours 

 may be thus given to the egg-lhell by the imagination of the fe- 

 male parent ; which fhell is previoufly a mucous membrane* in- 

 dued with irritability, without which it could not circulate its 

 fluids, and increafe in its bulk. Nor is this more wonderful than 

 that a fingle idea of imagination fhould in an inftant colour the 

 whole furface of the body of a bright fcarlet, as in the blufli of 

 fhame, though by a very different procefs. In this intricate fub- 

 ject nothing but loofe analogical conjectures can be had, which 

 may however lead to future difcoveries ; but certain it is that 

 both the change of the colour of animals to white in the winters 

 of fnowy countries, and the fpofs on birds' eggs, mud have fome 

 efficient caufe ; fince the uniformity of their production (hews 

 it cannot arife from a fortuitous concurrence of circumftances ; 

 and how is this efficient caufe to be detected, or explained, but 

 from its analogy to other animal facts ? 



2. The nutriment fupplied by the female parent in vivipa- 

 rous animals to their young progeny may be divided into three 

 kinds, correfponding with the age of the new creature. 1. The 

 nutriment contained in the ovum as previoufly prepared for the 

 embryon in the ovary. 2. The liquor amnii prepared 'for the 

 fetus in the uterus, and in which it fvvims ; and laftly, the milk 

 prepared in the pectoral glands for the new-born child. There 

 is reafon to conclude that variety of changes may be produced 

 in the new animal from all thefe fources of nutriment, but par- 

 ticularly from the firft of them. 



The organs of digeftion and of fanguiflcation in adults, and 

 afterwards thofe of fecretion, prepare or feparate the particles 

 proper for nourifhment from other combinations of matter, or 

 recombine them into new kinds of matter, proper to excite into 

 action the filaments, which abforb or atj|act them by animal ap- 

 petency. In this procefs we muft atteim not only to the action 

 ot the living filament which receives a nutritive particle to its 

 bofom, but alio to the kind of particle, in refpect to form, or 

 Cze, or colour, or hardnefs, which is thus previoufly prepared for 

 it by digeftion, fanguiflcation, and fecretion. Now as the firft 

 filament of entity cannot be furnilhed with the preparative or- 

 gans above mentioned, the nutritive particles, which are at firft 

 to be received by it, are prepared by the mother j and depofited 

 in the ovum ready for its reception. Thefe nutritive particles 

 muft be fuppoied to differ in fome refpects, when thus prepared 

 by different animals. They may differ in fize, folidity, colour, 

 and form j and yet may be fufficiently congenial to the living 



filament! 



