384 



MODE OF FORMATION OF GALL-STONES. [BOOK II. 



This increase in the frequency of the occurrence of gall-stones in 

 old people has been supposed by some to be due to their bile con- 

 taining an excess of cholesterin, but this explanation, as will be 

 subsequently argued, is an untenable one. As age advances and the 

 muscular activity of the body diminishes, as the habits become more 

 and more sedentary, the respiratory activity will certainly be dimin- 

 ished. If, then, there be any truth in the view that the liver is 

 rapidly and effectively drained of its bile in proportion as the 

 respiratory movements are active, and that a slow movement of the 

 bile is a primary condition for the formation of gall-stones, it will 

 follow that in old age one, at least, of the conditions favourable to 

 the formation of gall-stones exists. 



But the investigations of Charcot and Pitres 1 have shewn that 

 the unstriped muscular fibres which exist in the walls of the biliary 

 passages undergo remarkable atrophy in old age, so that the proba- 

 bility of the expulsion of any calculi which may be formed is much 

 smaller than at earlier periods of life. Thus, perhaps, we may in 

 part account both for the remarkable increase in the number of gall- 

 stones found after death as age advances, as well as for the compara- 

 tively small number of cases in which gall-stones give rise in old 

 people to attacks of biliary colic. 



But in what manner can an arrested or retarded movement of 

 the bile lead to the formation of biliary calculi ? If, in truth, such 

 a connection, as has been generally surmised, actually exists, it is, in 

 all probability, an indirect one, the retarded flow favouring the action 

 of agents which play a more direct part in the process. 



We have seen that biliary calculi in man are in the large majority 

 of cases composed mainly of cholesterin mixed in some cases with 

 calcium compounds of the bile colouring matters, whilst the con- 

 cretions formed mainly of the latter compounds are comparatively 

 rare. In order to explain the formation of gall-stones, we shall, 

 therefore, have to inquire into the circumstances which lead to the 



1 Charcot et Pitres, see Charcot, Legons sur les Maladies du Foie et des Reins, 

 p. 143. 



