609 



cells, the amitotic method of further multiplication would appear to be 

 the only possibility. 



The presence of occasional mitoses in the ciliated cells of the 

 epididymis of the horse remains a disturbing element to my hypoth- 

 esis, namely, that amitosis in ciliated cells results from the absence 

 of the centrosome, lost in the formation of cilia; and in extended 

 form, that amitosis follows disturbance of normal activity or the 

 integrity of the centrosome.^) 



It would simply be arguing in a circle to suggest that, since the 

 prevailing method of division also in the epididymis of the horse is 

 amitotic, the non-motile cilia here also develop from basal granules, 

 and that the exceptional mitoses result in consequence of virile cen- 

 trosomal remnants persisting after the cilia have been formed. This 

 is more probably the case, but in view of the observations of Fuchs 

 (1902) on the human epididymis which purport to show the absence 

 of basal granules in these cells, it seems safer for the present to regard 

 the phenomenon of amitosis in the cells of the epididymis proper, 

 where non-motile cilia (brush borders) are the rule, perhaps lacking 

 basal bodies in some forms, as due to the extreme specialization in- 

 volved, indirectly affecting the centrosome.^) In occasional instances 

 the conditions of the specialization may be insufficient to effect the 

 centrosome to the extent of incapacitating it for further function. 



The nature of the proliferative stimulus (the growth energy) is 

 more probably the same, whether the division proceeds by mitosis 

 or amitosis. Under normal centrosomal conditions cell multiplication 

 is accomplished mitotically. And incidental untoward or restraining 

 influences upon the centrosome would seem to limit proliferation to 



1) The presence of multiple amitoses in the non-ciliated cells of the 

 ducts of the lobster testis, likewise seems to contradict the hypothesis, and 

 suggests that the direct method of cell-division in the efferents ducts of the 

 testis is correlated with the specific function or location of these cells. 



2) FüCHS illustrates the ciliaothehumanvas epididymis as prolongations of 

 the filar mass of the protoplasm (concerned with discharge of secretion), in con- 

 trast to those of the vasa efferentia (mouse) which are attached to basal 

 granules. But von Lenhoss6k has shown that motile cilia (intestinal cells 

 of Anodonta) are also continuous with the filar mass beyond the basal granu- 

 les. Moreover, in my own preparations of the epididymis of the horse ter- 

 minal bars and basal granules are clearly discernible. In view of this data 

 Fdchs' distinction seems the less tenable. Non-motile as well as motile cilia are 

 more probably developed by intervention of basal granules derived from of the 

 centrosome. 



Anat. Anz. Bd. 43. Aufsätze. 39 



