32 METAMOKPHOSES OF MAN 



organization.* Next a number of little corpuscles or 

 nucleoli make their appearance in the .mass, and these 

 becoming surrounded by the gelatinous material, con- 

 stitute as many nuclei. From each of these a delicate 

 membrane is produced, which after a while completely 

 incloses the nucleus, and thus converts it into a 

 perfect cell. Bach cell, as soon as it is fully formed, 

 is capable of developing others by a series of pro- 

 cesses, admitted by botanists generally. These pro- 

 cesses are three in number. 1st. By budding from 

 its outer walls. 2nd. By division, which may take 

 place either by constriction of the entire cell, or by 

 the formation of partitions in its interior. 3rd. By 

 the development of free cells within it, which are 

 eventually set free by the bursting of the parent 

 one. 



Schwann sought for the same state of things in the 

 animal as in the vegetable kingdom. He fancied that 

 he had discovered the similarity, and endeavoured to 

 apply botanical theories to the development of the 

 animal. Closely following Schleiden's view, he gave 

 to the primary material, which we have styled sarcode, 

 the name of Cystoblastema.f According to him, this 

 amorphous substance was transformed successively 

 into the nucleolus, the nucleus, and finally the cell 

 itself. From the latter sprung every tissue, and 

 consequently every organ in the animal body. Even 



* M. de Mirbel, our distinguished physiological botanist, de-. 

 scribes a similar substance, which he calls cambium ; but according 

 to him, the corpuscles or nucleoli of which Schleiden speaks, are 

 only minute cavities gradually enlarging and forcing back the sur- 

 rounding matrix, which when more organized forms the cell-walls. 



f Kihttiq a vesicle, and /3\aar??jua, a bud, or, figuratively, pro- 

 duction. 



