EVOLUTION IN BIOLOGY. 283 



In the latter part of the seventeenth century, the 

 doctrine of epigenesis, thus advocated by Harvey, was 

 controverted, on the ground of direct observation, by 

 Malpighi, who affirmed that the body of the chick is 

 to be seen in the egg, before the punctum sanguineum 

 makes its appearance. But, from this perfectly correct 

 observation a conclusion which is by no means war- 

 ranted was drawn ; namely, that the chick, as a whole, 

 really exists in the egg antecedently to incubation ; and 

 that what happens in the course of the latter process 

 is no addition of new parts, " alias post alias natas," 

 as Harvey puts it, but a simple expansion, or unfold- 

 ing, of the organs which already exist, though they 

 are too small and inconspicuous to be discovered. The 

 weight of Malpighi's observations therefore fell into 

 the scale of that doctrine which Harvey terms meta- 

 morphosis, in contradistinction to epigenesis. 



The views of Malpighi were warmly welcomed, on 

 philosophical grounds, by Leibnitz,* who found in them 

 a support to his hypothesis of monads, and by Male- 



* " Cependant, pour revonir aux formes ordinaires ou aux atnes raate- 

 rielles, cette duree qu'il leur faut attribuer a la place de celle qu'on avoit 

 attribute aux atomes pourroit faire douter si elles ne vont pas de corps en 

 corps; ce qui seroit la me'tempsy chose, a peu pres comme quelques philo- 

 sophes ont cru la transmission du mouvement et celle des especes. Mais 

 cotte imagination cst bien eloignee de la nature des choses. II n'y a point 

 de tel passage ; et c'est ici ou les transformations de Messieurs Swammer- 

 dam, Malpighi, et Leeuwenhoek, qui sont des plus excellens observateurs de 

 notre terns, sont venues a mon secours, et m'ont fait admettre plus aise- 

 ment, que Panimal, et toute autre substance organised ne commence point 

 lorsque nous le croyons, ct que sa generation apparente n'est qu'une de"- 

 veloppement et une esp^ce d'augmentation. Aussi ai je remarque" que 1'au- 



