263 



At the present day things are changed. Recklinghausen 

 has pointed out that fixed cells exist in the cornea. Accord- 

 ing to Max Schultz, yelk-cleavage corresponds to a contraction 

 of the active cell mass. How, then, would the fixed non- 

 contractile cells divide ? Recklinghausen attempted the 

 solution of this question, and pointed out that fixed cells in 

 the process of inflammation acquire a certain degree of 

 activity. At the present day it has been proved by evidence 

 that they may become quite active. The question, howevei*, 

 has not been much simplified. The fixed are the older cells, 

 the active the younger cells. Do the old cells, then, we 

 inquire, become young again ? 



If facts do not assist us we need not undertake the dis- 

 cussion of this question. But facts do exist, and we must, at 

 least, sift these if we cannot give an explanation. 



In certain epithelial cells we have learnt to recognise an 

 endogenous generation. The young brood is slowly extruded 

 from the vesicular membranous envelope. Here the cell has 

 not thus become young, but a portion of the cell mass has 

 divided itself into segments, and has deserted the mother 

 mass. 



Whether the segment lying in the interior of an epithelial 

 cell of this kind — that is to say, the portion which serves as 

 the origin of pus-corpuscles — does not in its physiological 

 condition perform any movements, for the reason that it is en- 

 closed, or because in this state it is wanting in capability, is an 

 open question. It is only certain that a portion of a formed 

 element, intended for certain functional ends, has become 

 converted into an active body capable of acquiring another 

 shape. 



I have followed directly, in the tongue of the frog, a transi- 

 tion of this kind. With care the metamorphosis can also be 

 made out in the ramifying corneal cells, and capillary vessels 

 may be observed to throw out processes. 



We see thus that form-elements that serve distinct func- 

 tional ends, and which under certain physiological conditions 

 present very slight if any changes of external form, may under 

 special influences become active. 



The amoeboid movements recently investigated do not 

 distinctly correspond to the physiological ends of simple 

 form-elements. 



By putting these facts together, we see that several struc- 

 tures, in consequence of the process of inflammation, are 

 deprived of their functional ends, and are reduced to a con- 

 dition in which there is a tendency to procreation, that is to 



