8 



from the deficiency of words expressive of these iiniistial 

 motions and images, and from fear lest those thmgs which 

 1 had perceived both with the eye and the mind, should 

 remain obscure to the reader, 1 have committed nothing to 

 paper.* 



Many distinguished naturalists followed the coarse of 

 investigation which Miiller had successfully pursued, and 

 almost all of them drew their materials from the storehouse 

 of his observations, and as they took their facts from him, 

 so also they adopted his speculative opinions. Accordingly 

 we find the doctrine of simplification in the organization 

 both of the animal and vegetable kingdoms very generally 

 supported, and even carried to the extreme of denying the 

 existence of all organization in some classes of infusoria ; 

 and in connection with this doctrine, the theory of spontane- 

 ous generation, or the primary existence of organic animal 

 and vegetable forms from inorganic matter, was also main- 

 tained. Among those, who have advocated the doctrine of 

 a gradual developement of organisms from inorganic mole- 

 cules up to the highest and most complex organization in 

 .the animal and vegetable kingdoms, Lamarck and Oken 

 are conspicuous ; the former held to the gradual develope- 

 ment of animals as the circumstances of their condition 

 might require ; the latter considered the ocean as the great 

 storehouse whence terrestrial animals and vegetables, a 

 little metamorphosed to suit them to their terrene state, 

 were derived. 



To test this doctrine of a spontaneous generation. Prof. 

 Ehrenberg, in 1816, commenced a series of observations on 

 fungi, infusoria, and entozoa, objects that seemed more 

 especially to favor this hypothesis. In 1S19, he obtained a 

 direct and satisfactory proof of the existence of a germ in 

 every seed of fungus and mucor, and from the mass of seed, 

 which was present, the origin of those plants, from spon- 



* Ariimalcula Infusoria, Prajf. p. 18. 



