144 CONTENTS OF THE INTESTINAL CANAL. 



faeces varies according to the nature of the food, there is always a 

 relative excess of magnesia. In 100 parts of ash Fleitmann found 

 21-36 of lime with 10'67 of magnesia, and Porter 26'46 of lime 

 with 10' 5 4 of magnesia. Hence the ratio of the magnesia to the 

 lime in the excrements is as I : 2 or 2J. Alkaline chlorides 

 occur in the excrements in very small quantity (from 1'5 to 4'4^), 

 but carbonates are always present in the ash. Berzelius observed 

 that sand is always mixed with the excrements, and both Fleit- 

 mann and Porter have repeatedly noticed the same fact. 



The ash of the dung of herbivorous animals (the cow, the sheep, 

 and the horse) has been analysed by Rogers,* and, in essential 

 points, is the same as that of human excrement. It contains more 

 silica and sand, but that is easily accounted for. It is worthy of 

 remark that Rogers found scarcely any traces of alkaline car- 

 bonates in these ashes. 



Very soluble salts only enter into the solid excrements in large 

 quantity, when they excite diarrhoea ; Laveran and Millonf have 

 obtained this result with sulphate of soda and acetate of potash, 

 and I have done so with phosphate of soda. 



The presence of crystals of phosphate of ammonia and magnesia 

 in human feeces, was for a time regarded as a sign of a grave 

 disease, namely typhus; pathologists are, however, now generally 

 of opinion that such is by no means the case, and that these 

 crystals often occur in perfectly normal evacuations, although it 

 is only under specially favouring conditions that they are found 

 in large quantity. It cannot, however, be denied that, in certain 

 diseases of the intestinal canal, in which the secretions and the 

 contents of the bowels are especially prone to decomposition, as 

 in typhus, cholera, and certain forms of dysentery, these triple 

 phosphates are found in an extraordinary quantity, on examining 

 the evacuations by means of the microscope. 



We have already pointed out that, in all cases in which the 

 food passes more rapidly than usual through the intestinal canal, a 

 larger quantity of undecomposed bile is always found ; hence this is 

 the case after the use of saline and acrid purgatives, and in the 

 simplest forms of catarrh al diarrhoea, as PettenkoferJ himself 

 proved. That in jaundice, dependent on occlusion of the common 

 biliary duct, even the products of the decomposition of the bile 

 should not occur in the stools, is a fact scarcely requiring mention. 



* Ann. d. Ch. u. Pharra. Bd. 65, S. 85-99. 

 t Ann. de Chim. et de Phys. T. 12, p. 135. 

 $ Ann. d. Ch. u. Pharm. Bd. 53, S. 90. 



