The Structure and Functions of the hfemolymph Glands and Spleen. 43 



Average weight of body .... 185 grammes, 



Average weight of spleen . . . 0,702 grammes. 



Average weight of glands . . . 0,081 grammes. 



These results apply to the tame rat only, the weight of the glands 



in the wild rat is very much increased proportionately, even as much 



as three or four times. 



I have been unable to find any relation between the total weight 

 of the glands and that of the spleen in different rats. For example 

 in the case of an abnormally small spleen, the hœmal glands showed 

 no signs of enlargement, as would certainly be expected if the function 

 of haemal glands was subsidiary to that of the spleen. The evidence 

 given by the experiments of Vincent [17 c] is in accordance with these 

 observations: in a number of Splenectomy experiments upon dogs, he 

 was unable to dedect any hypertrophy of the hsemal lymphatic glands, 

 even after a period of eighteen months; nor was there any appreciably 

 increased phagocytosis apparent in any of these glands. 



XI. Function of the haemolymph organs. 



The result of the present investigation has been to further con- 

 firm the view as to the blood destroying powers of hgemolymph glands, 

 and to show that the process is more widespread than has as yet 

 been suspected. It has also resulted in the conclusion that the pro- 

 cesses are identical in the spleen, haemal, haemal lymphatic and lym- 

 phatic glands.^) 



Another undoubted function of all the members of the series, is 

 the elaboration of white corpuscles. This process proceeds in the germ 

 centres, in which stages of active karyokinetic division may be 

 frequently observed. Mitosis also occurs in the general lymphoid tissue, 

 where nuclear figures are often seen. 



The glands have a further minor function, namely the destruction 

 of leucocytes. This occurs by phagocytosis in many glands, but par- 

 ticularly in those organs which are abundantly supplied by lymph. 

 Disintegration also takes place in another form. Schumacher has ob- 



*) If such processes take place in lymphatic glands, which is extremely 

 doubtful. 



