THE METABOLISM OP THE BODY. 



431 



the seat of a complex metabolism, though neither the changes 

 themselves nor their purpose are well understood. 



Nevertheless, it must be admitted that to recognize this was 

 a great advance upon the view that the spleen had no impor- 

 tant function, and that this was shown by the removal of 

 the organ without 

 change in the ani- 

 mal's economy. 



But to believe 

 that there are no 

 such changes, and to 

 have clear proof of 

 it, are two different 

 things. As a matter 

 of fact, closer study 

 does show that in 

 some animals there 

 are alterations in the 

 lymphatic glands 

 and bone - marrow, 

 which organs are 

 undoubtedly manu- 

 facturers of blood- 

 cells. 



These changes 

 are unquestionably compensatory, and that other similar ones 

 corresponding to comparatively unknown functions of the 

 spleen have not as yet been discovered is owing likely to our 

 failures rather than their real absence. We dwell for a mo- 

 ment on this, because it illustrates the danger of the sort of rea- 

 soning that has been applied in the case of this and other or- 

 gans; and it shows the importance of recognizing the force 

 of the general principles of biology, and also the desirability 

 of Refraining from drawing conclusions that are too wide 

 for the premises. In every department of physiology it must 

 be more and more recognized that what is true of one group 

 of animals is not necessarily true of another, or even of other 

 individuals, though the differences in the latter case are of 

 course usually less marked. We have referred to this be- 

 fore, and shall do so again, for it is as yet but too little conr 

 sidered. 



Fib 



■Portion of spleeu of cat, showing Malpighian 

 (lymphatic) corpuscle (after Cadiat). A, artery 

 around which corpnecle is placed; B, meshes of 

 spleen-pulp, injected; C. artery of corpuscle ramify- 

 ing in lymphatic tissue. The clear space around 

 corpuscle represents a lymphatic sinus. 



