29 



II was declared in the early period of tissue-cullivalion. 

 Ihal all cells cullivaled in vilro, dedifl'erenlialed lo a pri- 

 milive indilTerenl cell lyi)e; il can Iherelore he slated as 

 a very impoiianl and I'undanienlal fad thai ecloderin and 

 mesenchyme do nol change Iheir characler. This seems 

 lo indicate thai i)r()l)al)ly the physiological character of 

 Ihc cells also should remain constant. This fact, certainly, 

 gives us an opportunity to investigate the |)hysiological 

 characteristics of the various tissue cells outside Ihe body 

 and perhaps elucidate the more or less antagonistic cytologi- 

 cal inlei-actions between the various types of tissue cells in 

 the organism. 



The problems to be investigated by the tissue-cultivaliou 

 method are unlimited and. as mentioned before, if used in a 

 l)roper critical manner, it is the most rational method for the 

 study of physiology and pathology. During the short time 

 that this method has been propagated into the many different 

 lines of biology, many more or less hazardous conclusions 

 have been brought out. nu)stly built on very imjierfect 

 technique. 



The histogeny of the various intercellular substances, such 

 as the different fibrillae of the connective tissue, the substan- 

 ces which link the cells together in cartilage and bones, etc.. 

 will find a good method for investigation in the tissue cul- 

 tivation. The old question of the origin of the connective, 

 tissue fibrils was taken up by Bait sell ^)*^)'-') and later by 

 M. Lewis 3^9^ by the tissue-culture method. Bait sell re- 

 presents the idea that the fibrils have their origin in the 

 plasma and can be reproduced without the presence of living 

 cells, but by mere mechanical factors; he explains it as a 

 transformation of the amicronic fibrin particles in the plasma 

 and i)robably under the influence of the different enzymes 

 in the blood. It is known from the chemistry of colloids 

 that different mechanical factors have a denaturing effect 

 on the colloidal solutions and without doubt the same phe- 

 nomenoi is dealt with here. On the contrarv M. Lewis 



