OiDlUM ALBICANS. 199 



> 

 mouth, acts, no doubt, favorably (Robin), but a decidedly acid 



decomposition and formation of lactic acid is not necessarily 

 required, for thrush-fungi are found without any acid re- 

 action. Among the causal circumstances, the peculiar properties 

 of the mucous membrane are especially not to be passed over 

 silently ; such as its loose state, its unevermess on the surface, 

 and its readiness to cast off its epithelial cells, conditions which, 

 like the separation of the membrane of the tongue, are of tran- 

 sient, but frequent, occurrence in the mouth. Add to that the 

 repose of the mucous membrane in question, which is the more 

 conducive to implantation the greater it is; next the lessened 

 moisture and occasional drying up of the mucous membrane, as 

 often happens in the upper parts of the intestinal tube, and 

 the stratification of the epithelium, which prepares the way for 

 the fungus the better the more abundant it is. Thrush is therefore 

 met with most frequently and remains longest on those places 

 of the mucous membrane of the mouth which possess the 

 thickest epithelium on the hard palate, accordingly, behind and 

 on the inner part of the lips and cheeks. The papillary bodies 

 of the mucous membrane appear likewise to stand in a certain 

 relation to the thrush-fungus, for the latter seems to have a 

 liking for the places where the papillse are thickest, such as on 

 the hard palate, on the cheeks, the lips, on the back of the tongue, 

 and on the oesophagus, though the fungus occurs sometimes in 

 the larynx, where these papillse, are not found. 



The properties of the epithelium seem mostly to deserve our at- 

 tention. Several questions must, at present, be left unanswered, 

 as to whether the coherence of the epithelial cells be at first 

 increased and afterwards decreased ; whether the thrush-membrane 

 falls off at a later period ; whether the earlier irregularity in the 

 epithelium, which facilitated the growth of the fungus, be equalised; 

 whether the later epithelial crop thrives more rapidly than the 

 fungus itself, or whether the secretion, which is at first viscous, 

 loses afterwards its viscosity. 



Catarrh is, of all diseases of the mucous membrane, that 

 which offers the above-mentioned undoubted causes of aphtha 

 most abundantly, presenting them all, whether they be of a 

 mere mechanical, local, or constitutional origin, acute or chronic. 

 It causes, at all events, changes in the arrangement of the epi- 

 thelium and in its secretions, if only because it is likely to lay 

 bare the secerning mucous membrane. Those changes which 



