DIGESTION OF POOD. 351 



it is infinitely better to admit ignorance than attempt to ex- 

 plain by principles that do violence to our fundamental con- 

 ceptions of life processes. To introduce " ferments " to explain 

 so many obscure points in physiology, as the conversion of 

 peptone in the blood, for example, is taking refuge in a way 

 that does no credit to science. 



Without denying that endosmosis, etc., may play a part in 

 the vital processes we are considering, we believe a truer view 

 of the whole matter will be ultimately reached. In the mean 

 time we think it best to express our belief that we are ignorant 

 of the real nature of absorption in great part ; but we think 

 that, if the alimentary tract were regarded as doing for the 

 digested food (chyle, etc.) some such work as certain other 

 glands do for the blood, we would be on the way to a truer con- 

 ception of the real nature of the processes. 



It would then be possible to understand that proteids, either 

 in the form of soluble or insoluble substances, including pep- 

 tone, might be taken in hand and converted by a true vital 

 process into the constituents of the blood. 



If we were to regard the kidney as manufacturing useful 

 instead of harmful products, the resemblance in behavior would 

 in many points be parallel. "We have seen that physical expla- 

 nations of the functions of the kidney have failed, and that it 

 must be regarded even in those parts that eliminate most water 

 as a genuine secreting mechanism. 



We wish to present a somewhat truer conception of the 

 lymph that is separated from the capillaries and bathes the 

 tissues. 



We would regard its separation as a true secretion, and not 

 a mere diffusion dependent wholly on blood-pressure. The 

 mere ligature of a vein does not suffice to cause an excess of 

 diffusion, but the vaso-motor nerves have been shown to be 

 concerned. The effusions that result from pathological pro- 

 cesses do not correspond with the lymph — that is, the nutrient 

 material — provided by the capillaries for the tissues. These 

 vessels are more than mere carriers ; they are secretors — in a 

 sense they are glands. We have seen that in the foetus they 

 function both as respiratory and nutrient organs in the allan- 

 tois and yelk-sac, and, in our opinion, they never wholly lose 

 this function. 



The kind of lymph that bathes a tissue, we believe, depends 

 on its nature and its condition at the time, so that, as we view 



