96 SCIENCE PROGRESS. 



ment which stands in the first paragraph of Whitman's 

 work, that he believed that in cell-formation lies the whole 

 secret of organic development. There are, says Schwann, 

 two possible theories on the subject of organic development: 

 (i) The organism theory, namely, that there is an inherent 

 power modelling the body in accordance with a predominant 

 idea. (2) The physical theory, namely, that the funda- 

 mental powers of organised bodies agree essentially with 

 those of inorganic nature. Rejecting the former of these 

 two theories as being outside the domain of physical science, 

 Schwann went on to write : x " We set out with the sup- 

 position that an organised body is not produced by a 

 fundamental power which is guided in its operation by a 

 definite idea, but is developed according to the blind laws 

 of necessity by powers which, like those of inorganic 

 nature, are established by the very existence of matter. 

 As the elementary materials of organic nature are not dif- 

 ferent from those of the inorganic kingdom, the source of 

 the organic phenomena can only reside in another com- 

 bination of these materials, whether it be in a peculiar 

 mode of union of the elementary atoms to form atoms of 

 the second order, or in the arrangement of these con- 

 glomerate molecules when forming either the separate 

 morphological elementary parts of organisms, or the entire 

 organism. We have here to do with the latter question 

 solely, whether the cause of organic phenomena lies in the 

 whole organism or in its separate elementary parts. If 

 this question can be answered a further inquiry still re- 

 mains as to whether the organism or its separate elementary 

 parts possess this power through the peculiar mode of 

 combination of the conglomerate molecules or through the 

 mode in which the elementary atoms are united into con- 

 glomerate molecules." 



Is it not perfectly clear from this that Schwann fully 

 recognised that there was a further question underlying 



x Th. Schwann, Microscopical Researches into the Accordance in the 

 Structure and Growth of Animals and Plants. Translated by Henry 

 Smith. London: Printed for the Sydenham Society, 1847. 



