112 CORRELATIONS OF PARTICULAR ORGANS 



few of them. In the first place it would be desirable 

 to find out where the defensive ferments arise, and 

 whether they can be met with inside the individual 

 cells themselves. It is, for instance, conceivable that 

 the walls of the intestine, and perhaps also the cells 

 of the liver, are always provided with definite fer- 

 ments for the purpose of further reducing- substances 

 which, though insufficiently decomposed, pass 

 through the gut epithelium ; and it is very probable 

 that the leucocytes play an important part in this con- 

 nection. They circulate rapidly through the w^hole 

 organism. They are to be looked on as protective 

 organs, which, to use a metaphor, overlook every- 

 thing with a view to finding out whether order 

 prevails. Some products are eliminated by being 

 absorbed into the body of the leucocytes (phago- 

 cytosis) ; others are attacked by their ferments, and 

 so broken up, and deprived of their characteristic 

 structure. Finally, as mentioned before, the separate 

 organs have to be considered, particularly the 

 kidneys. 



But the most important advantage of the methods 

 we have described is, that they will enable us to 

 study the reciprocal dependence of individual organs. 

 Suppose, for instance, we remove the thyroid gland ; 

 we then anticipate that another organ, some of whose 

 functions depend on this gland, Avill have its meta- 

 bolism interfered with, and will in consequence give 



