978 



few giant-cells are disting;iiisliable, for the greater part, to all appear- 

 ance, normal. Generally the nmnber is not larger than de Kekvily 

 (1912) assigns for the spleen of the normal adult cat. He gives the 

 numbers 2 per cm' to 20 mm", so it seems to be rather fluctuating. 



Quite the same ma}' be noted in the spleen of a kitten 46 days 

 old. The number of the giant-cells seems to be rather smaller in 

 this case. Anyhow the appearance does not differ from that of an adult 

 cat's spleen. It is evident, then, that the giant-cells do not disappear 

 completely, as indeed de Kervily has been able to demonstrate for 

 the spleen of the majority of adult mammalia. In the Leyden 

 laboratoiy 1 also have been enabled to detect giant-cells in all sorts 

 of mammals except man. 



The answer to the original question was now found -. the giant- 

 cells disappear from iUe cat's spleen through degeneration and dis- 

 solution, especially in the 2'"^ week after birth and in the large veins. 



This does not tit in with Wright's view. As early as 1906 

 Wright described a process of extrusion also in the spleen of the 

 kitten, but this process he holds to be a formation of blood- 

 platelets. The process described by me is certainly not formation 

 of bloodplatelets but a degeneration. May it be possible that Wright 

 has observed what I have seen, but that he gives a different inter- 

 pretation? The process described by me leaves no room for another 

 explanation. 



Wright's description is about as follows: 



The megakaryocytes form pseudopods, which they send out into 

 the small capillaries. These pseudopods are stained less intensely at 

 the margin and have a granulated appearance. Small pieces are now 

 constricted off, they are the thrombocytes. Wright does not mention 

 the age of the kitten upon which he experimented. Of this process 

 he gives fourteen micro|)hotographs, which are anything but clear, 

 but still they resemble my findings too closely to conclude that they 

 are widely different from Wright's. He obtains these appearances 

 b}' means of a special staining method of his own device with the 

 exclusion of all others. As far as I know, Ogata (1912) is the only 

 one who corroborates Wright's histological findings, in spite of 

 Schridde's failure (1907) to demonstrate a similar pi-ocess in man. This, 

 Ogata asserts, was because Schridde was obliged to work with post 

 mortem material, whereas Wright and himself were enabled to work 

 with "lebenswarm fixierten Praparaten". As to the latter I was in 

 the same condition. In this connection it seems strange that Ogata 

 could not get good preparations when using Wright's method, and 

 succeeded when applying the ScHRiDDE-azure Il-eosin method. Further- 



