12 



CELL-NUCLEI. 



[sect, 7, 8. 



According to this, the process would be a purely chemical and not a physical 

 and still less a specifically vital one. In opposition to this, however, Harting 

 (xded.Lanc.Sept.j851) recently observed a formation of pseudo-cell from 

 albumen on shaking it with quicksilver, in which case the albumen certainly 

 became solid m exactly the same manner as on merely shaking it with water 

 or other flmd {Mdsms, Bull.d.1' Ac.d.Belg. ; 1850. Harting, \. c). Besides 

 it will scarcely be necessary to assume the presence of chemical influence' 

 when by mixing together albumen and chloroform, you produce albumen- 

 membrane ; by mixing caseine of serum and fat, caseine-membrane : and by 

 mixing chondrme and chloroform, chondrine-membrane, as has been observed 

 by Panum (see Arch.f. path.Anat.iv. 2). 



2. — Of the Cells. 

 § 7. The Cells {ccllulce), also called elementary cells or nuclear cells 

 are completely closed vesicles, 0-005 - o-oi (^ - M f a line in 



average size, in which a special envelope, 

 the cell-membrane, and contents are to be 

 distinguished. The latter always consist 

 of fluid and of formed particles of this or 

 of that kind, and of a special roundish 

 body, the cell-nucleus, which again con- 

 tains fluid and a still smaller corpuscle, 

 the nucleolus, in its interior. These cells, 

 which are to be considered as being en- 

 dowed with special vital powers, and ca- 

 pable of taking up and consuming matter, 



m ^,' s ca v f ity he 5 ep w^r e , ? Jg as weli as of S rowtl1 a *d of multiplication, 

 two nuciei.-Magnified 380 times. not only solely constitute the body of the 

 higher and of most of the lower animals in the first periods of life 

 but also almost solely produce the higher elementary parts of the 

 fully formed body. Nay, even in fully grown animals, the elements 

 are met with m very many places in the simple condition of cells • 

 and, as such, participate more or less, often quite decisively, in the 

 organic functions. 



§ 8. A closer inspection of the condition of the cells shows 

 the following. Their fundamental form is that of a sphere or lens 

 which belongs to all cells in their first period of life, to many as 

 especially those situated in fluids (blood corpuscles and others) 

 constantly. The following forms appear more rarely : 1 The 

 polygonal (pavement epithelial cells). 2. The conical or pyramidal- 

 shaped (ciliated epithelium). 3. The cylindrical (cylindrical epi- 

 thelium). 4. The fusiform (contractile fibre-cells). 5 The 

 squamous (epidermic plates). 6. The stellate (nerve-cellsj The 



