114 



SIMPLE HISTOLOGICAL ELEMENTS. 



That fibres of any kind are ever formed by the mere conjunction 

 of nuclei, must be, for the present, regarded as very improbable. 

 Simple fibres are found as a permanent development in some false 

 membranes, so called, as shown by Fig. 52. 



CHAPTEK IV. 



CYTOLOGY. CELLS. 



THE description of the cells (and their development and function), 

 from which the tissues are originally formed, constitutes the depart- 

 ment of histology termed Cytology. 1 These are closed vesicles, 

 usually of a globular form, varying from ^ to g^ of an inch in 

 diameter, and consist of the five following structural elements: 



1. The cell-wall. 



2. A contained fluid. 



3. Granules floating in the fluid. 



4. A nucleus. 



5. A nucleolus. 



Cells showing the cell-membrane, the 

 contained granules, the nucleus, and 

 the nucleolus. 1 and 2. The typical 

 spherical form. The rest as changed 

 by pressure. 



1. The cell-wall is formed of simple membrane, and, of course, is 

 an albuminous compound, but is not fibrine. Though varying much 

 in thickness in different instances, it presents nothing peculiar. It 

 is generally soluble by acetic acid. The walls of epithelial cells, 

 however, are not thus dissolved after they become corneous, though 



1 From XUTO;, a cavity or cell, and Xoj/of, description. 



