538 DEVELOPMENT OF THE SIMPLE TISSUES, BY S. STRICKER. 



well as all the glandular organs that project from the intestine. 

 The relations of the first rudiments of the urino-genital appa- 

 ratus to the middle germinal layer have already been given by 

 Waldeyer, see vol. ii., p. 192, et seq. 



DEVELOPMENT OF THE SIMPLE TISSUES IN THE EMBRYO. 



In regard to the origin of the cells, little remains to be 

 added to that which has been already stated in vol. i., p. 35, of 

 this Manual. I have, however, devoted much attention to 

 the process of cell division, and have found that it may be 

 observed with tolerable facility in inflamed tissues. It is 

 only requisite to maintain the tissues under observation in 

 conditions that are favourable to their vitality.* The results 

 thus obtained by direct observation are identical with the 

 conclusions that have long been arrived at theoretically. The 

 account formerly given, however, does not appear to be quite 

 accurate. It is not necessary that a cell should assume the 

 form of a finger biscuit before it divides. It divides either 

 with the constant performance of amoeboid movements, the 

 body of the cell, owing to these movements, separating into 

 two masses, united by a thin thread which ultimately 

 ruptures, or the cell forms a ball-like mass, in which a line 

 of division becomes visible, that sometimes disappears, and 

 then again reappears, and so on, till finally the line becomes 

 defined, in such cases we are led to the conviction that 

 division has really taken place when one or both parts 

 resume their amoeboid movements, and finally separate from 

 each other. The cells, however, as a rule, do not part com- 

 pany; they divide, and the cement existing between them 

 alone indicates that the division is complete. 



The examination of the process of cell multiplication in 

 inflamed tissues has led to certain modifications of the cell 

 theory. It has demonstrated that cells which have already 

 attained such an age that amoeboid movements can no longer 

 be observed in them (fixed connective-tissue corpuscles) may 

 under certain circumstances (as inflammation and its conse- 



* Strieker, Stndien. 



