BRITISH ASSOCIATION. 57 



extending, many of the hospitals had had to restrict its use on account of the ex- 

 pense ; and the result of the recent discoveries would be that physicians, when 

 prescribing bark alone, would give the preference to young bark. 



On the Reason why the Stomach is not Digested by its own Secretion during 

 Life, by Dr. Pavy. — How is it (he observed) that the stomach, composed as it ia 

 of digestible materials, escapes being digested itself, whilst digestion is being car- 

 ried on in its interior ? The question here raised must be admitted to be one of 

 the utmost interest and importance to us all, becaui^e it touches upon the means 

 by which we escape after every meal we consume from the occurrence of an event 

 which would inevitably prove fatal to life. Hunter noticed that the stomach was 

 Busceptible of being attacked by the digestive liquid after death, and accounted for 

 its power of resisting destruction during life by reference to the ' living principle.' 

 The stomach, he says, which at one instant, that is, while possessed of the living 

 principle, was capable of resisting the digestive powers which it contained, the 

 next moment, namely, when deprived of the living principle, is itself capable of 

 being digested. In illustration, he further says, " if it were possible for a man's 

 hand to be introduced into the stomach of a living animal, and kept there for some 

 considerable time, it would be found that the dissolvent powers of the stomach 

 could have no effect upon it ; but if the same hand were separated from the body 

 and introduced into the same stomach, we should then find that the stomach would 

 immediately act upon it." This statement, however, fails to stand the test of ac- 

 tual experience. Bernard, of Paris, ingeniously contrived to introduce the hind 

 legs of a living frog through a fistulous opening in the interior of a digesting sto. 

 mach, and found that they underwent digestion, notwithstanding that the life of 

 the animal was maintained. My own experience enables me to testify to the accu- 

 racy of this result ; and further, I have found that the tip of a living rabbit's ear 

 has similarly yielded to the influence of the digestive menstruum. The " living^ 

 princi'Dle " must, therefore, be discarded, as insufficient to account for the state of 

 eecurity under which the living stomach exists. To replace the refuted influence 

 of the " living principle," it has been suggested that it is the epithelial lining which 

 gives to the stomach the immunity from destruction it enjoys diiring life. The 

 Btomach, it has been said, is lined with an epithelial layer, and this, with the mucus 

 secreted, acts as a kind of varnish in protecting the deeper parts. Whilst diges- 

 tion is proceeding, the epithelium and mucus are constantly being dissolved, like 

 the food contained in the stomach ; but a fresh supply being as constantly pro- 

 • duced, the organ is thereby maintained intact. Death taking place, and the epi- 

 thelial layer being no longer produced, the gastric juice, after acting upon and dis- 

 solving it, reaches the deeper coats, and then, continuing to exert its influence, 

 may ultimately, the temperature being maintained sufficiently favourable for the 

 purpose, occasion a perforation of the organ. This view, however, like Hunter's 

 •'living principle," fails to stand when submitted to the test of experiment ; for I 

 have found that a considerable sized patch of mucous membrane may be removed, 

 and food will afterwards be digested without the slightest sign of attack being 

 made upon the deeper coats of the organ. Indeed, it might almost be assumed 

 upon reflection, that something more constant — that some condition presenting 

 less exposure to the chance of being influenced by external circumstances than 

 that supplied by the existence of an epithelial layer, would be required to account 



