92 THE CELL DOCTRINE. 



come very small by successive segmentation (diame- 

 ter .008 millimetre, .00031396 of an inch), these little 

 bodies take the name of embryonic cells. 



According to M. Robin, these cells dissolve. 

 From the fusion results a blastema, in the midst of 

 which nuclei make their appearance. This is known 

 as genesis. It is the second and most frequent mode 

 of the formation of anatomical elements. It is char- 

 acterized by the appearance of an anatomical ele- 

 ment in a fluid termed blastema, in which the 

 element did not previously exist. 



3d. Epigenesis. When the embryonic cells dis- 

 solve, the embryo-plastic nuclei are produced by 

 genesis in the blastema which results from their 

 fusion. Then little cone-like prolongations of trans- 

 parent matter are observed at the extremities of the 

 nuclei, giving rise to the fusiform bodies, which are 

 the connective tissue corpuscles. This mode of for- 

 mation by growth upon another element is known 

 as epigenesis, and is the mode in which connective 

 tissue is developed. The prolongations of these fu- 

 siform bodies constitute the non-elastic fibres or 

 white fibrous tissue element of connective tissue. 

 Sometimes the substance deposited by epigenesis 

 upon the nucleus has several prolongations, forming 

 a stellate cell or connective tissue corpuscle. These 

 fusiform and stellate cells are likewise known as 

 embryo-plastic or jibro-plastic bodies, and this latter 

 term is a most common one in French histology. 



The elastic fibres of connective tissue are likewise 

 formed by epigenesis, but upon special nuclei, and 

 the prolongations are insoluble in acetic acid. 



