COMPARATIVE HISTOLOGY AND PHYSIOLOGY OF THE SPLEEN. 311 



artificial anaemia does not stimulate the spleen to haematopoietic activity. Muir * pro- 

 duced anaemia in two rabbits with similar results. One rabbit was bled to the extent of 

 2 "2 per cent, of the body weight ; the red corpuscles fell as low as 2,846,000 from 

 6,181,000 ; but nucleated red cells did not appear in the blood, nor did he find any in 

 the spleen on examining it in the fresh condition. He was good enough to give me the 

 spleen for examination. 



Each Section of the Spleen shows a portion of one or sometimes of two giant cells. 

 Erythroblasts and nucleated red cells are present in very small numbers. The follicles 

 contain many leucoblasts, and there are numerous small lymphoid cells or uninucleated 

 leucocytes in the pulp. Fairly large numbers of coarsely granular protoplasmic cor- 

 puscles, some of which are vacuolated, are found in the pulp, and a few in the follicles. 

 Numerous pigment-holding cells occur both in the follicles and pulp, and ■ large masses 

 of coarse granules are present in the splenic veins. 



These facts tend to show that, if blood formation in the spleen does not follow the 

 production of artificial anaemia, the giant cells do not appear in it in any consider- 

 able numbers, and that, with few erythroblasts and nucleated red cells in the spleen, there 

 are very few giant cells present in it. 



And the occurrence of giant cells in large numbers in the spleen of dogs rendered 

 anaemic, and of young animals actively forming blood, cannot, I consider, be explained 

 on the theory that the giant cells are phagocytes ; while the fact that I have never found 

 red blood- corpuscles within the giant cells is to me negative evidence strongly against 

 that theory. 



PART III. 



Methods — Bibliography — Description of Figures. 



Chapter VI. 

 Methods. 



The spleens were invariably obtained as fresh as possible. 



Of the three principal methods of hardening employed, that of the Physiological 

 Laboratory of the University of Edinburgh has given, on the whole, the best results. 

 Small portions of the spleen are placed in methylated spirit for twenty-four hours, then 

 in a mixture of Muller's fluid and methylated spirit (in the proportion of three of the 

 former to one of the latter by volume) ; the fluid is changed on the fourteenth day ; on 

 the twenty-ninth day the tissue is transferred to methylated spirit, previously washed 

 well in water to remove the bichromate salt, and after a fortnight in alcohol the tissue 

 is ready for section. Flemming's strong solution (chrom-osmic-acetic acid), followed by 

 alcohol, gave very good results, but his weak solution produced alteration in some of the 



* Mum (47), p. 497. 



