386 PPIYSIOLOGY, CHEMISTRY, AND MORPHOLOGY. 



But here we enter the very obscure domain of the origin and develop- 

 ment of life. You know how much the determining causes of heredity 

 and evolution have been discussed, and how the Darwinian laws, 

 although remaining fundamentally the same, have been profoundly 

 modified as far as regards the conditions of their development. Wliile, 

 for example, it would seem that we must not admit the hereditary 

 transmission of acquired characters in animals, the study of the 

 development of plants tends to change our too absolute ideas as to 

 the relations between autogeny and phylogeny and to give to evolution 

 a periodic character established by hereditj',' and by the influence of 

 time and the environment. 



At all events it is always organization, independently of the causes 

 by which it was or is determined, that fixes and molds the activities 

 of an organism, although, in the causal succession of i)henomena, 

 functional differentiations i)recede morphological differentiations, and 

 are sometimes manifested in a tissue whose details can not be shown by 

 our present means of investigation. Besides, even tlie so-called amor- 

 phous protoplasm is developed little by little into a very complex 

 whole, and it is even thought that it may be considered as a colony of 

 microorganisms.^ 



The cell, according to this theory, loses its fundamental character of 

 morphological unity and is supposed to be made up, like a higher 

 organism, of a multitude of very much smaller units that probably 

 differ from each other. Finally let us, with these, go beyond the woild 

 actually cognizable by the senses, let us imagine an internal weft made 

 up of unities still more minute and more simple that bear the same 

 relation to organized forms as molecules do to inorganic matter. The 

 structure of these elements and the morphological relations that unite 

 them ought not, however, to be considered as the bed through which 

 flows the torrent of life, but as the mechanism which elaborates and 

 develops its manifestations. 



We know, besides, that the morphological element has no stable 

 basis, and that it even becomes modified according to the various func- 

 tions it has to perform. Thus it is that the anatomical changes of an 

 element may sometimes inform us as to the condition of its nutrition, 

 whether it has been in action or remained long at rest, and whether 

 there are developing within it those mysterious processes by which a 

 cell prepares for reproduction. From all this it clearly results that by 

 the study of conditions and of the morphological modifications that 

 determine, accompany, or follow a functional act, much more than by 

 chemical researches, we can perhaps some day explain many a weighty 

 problem of physiology, if not those fundamental processes character 



'M. E. Heckel. "La Pdriodicitc dvolutive des auiruaux et des vegdtaux," Revue 

 scientifiquc, T. LII, page G49, 1893. 



' R. Altmaiiu. "Die Genese dcr Zelle." Beitriige zur Physiologie. Carl Liulwig's 

 Festschrift, Leipzig, 1887, page 235. 



