SECRETION AND EXCRETION. 



179 



prevented him from speaking ; it was enormously enlarged and 

 burst open, jaws swollen, &c., &c. Over one hundred leeches had 

 been applied to reduce the inflammation. 



CHAPTER X. 



SECRETION AND EXCRETION. 



WE have seen, in the preceding chapters, that there are arrange- 

 ments for circulating the blood and for keeping it pure. The great 

 object in these arrangements seems to be, that the substances re- 

 quired in the different parts of the system may be separated from 

 the blood in a proper state. There is a class of bodies, known by 

 the name of glands, whose office appears to be principally to form 

 different secretions. Thus, the liver is a gland, which is said tq 



