RESOKPTIVE DIGESTION. 99 



through a vicarious secretion of a digestive fluid, a soluble 

 ferment, by the proper tissues of the body. 



We will take for illustration the familiar process of the 

 resorption of the .roots of the temporary teeth. This is a 

 physiological process, as all other resorptive processes are. 

 It is brought about by the action of certain cells which have 

 become known as osteo- or odontoclasts. It has been claimed 

 that the osteoclasts are really osteoblasts, that have changed 

 their function from that of builders of bone to absorbents of 

 bone. The distinction is not important in this lecture. These 

 may be only the ordinary connective tissue cells of the part in 

 immediate proximity with the part to be removed, which have 

 temporarily taken on new functions, the secretion or elabora- 

 tion of a soluble ferment for the removal of the roots of those 

 teeth which are no longer wanted. These cells perform this 

 act in an indirect manner. It is plain that these roots are not 

 removed by any mere mechanical force. These cells have no 

 physical power of gnawing into them. They secrete a soluble 

 ferment, or analogous body, which digests them, breaks them 

 down, and fits their material for entrance into the blood 

 streams by osmosis, just as solid ingesta in the stomach is 

 broken down and fitted to enter the circulation by osmosis. 

 There seems to be no foundation for the notion that the re- 

 sorbed product of these roots may not form proper pabulum 

 for the building up of other tissues; that the absorbed product 

 is necessarily excreted. Resorption is not a process for the 

 forming of waste products. 



As this process has been pretty closely studied, we will 

 examine it a little further. From decay and other accident 

 the temporary teeth are very liable to lose their pulps, which 

 very often, we may say generally, results in the formation of 

 alveolar abscess at the apex of their roots. If such an abscess 

 exists at the time the resorption should take place, such re- 



