THE EXAMINATION OE FJECES 633 



Europeans in the tropics give an average stool per diem of 130 grni. 



Natives give an average stool of 2t,t, grm. per diem. 



The reaction of a normal stool is nearly neutral to litmus, acid on 

 fasting, faintly alkaline when taking milk. In most cases of diarrhoea 

 they are decidedly alkaline. All stools should be examined as soon 

 as possible after being passed. 



Macroscopic mucus usuall}' means catarrh in the large intestine. 



Microscopic mucus usually means catarrli in the small intestine. 



Earth eaters pass pale stools which may in this respect resemble 

 obstructive jaundice. Those who eat coal-dust and take iron or bis- 

 muth have blackish stools which may resemble mekena. The stools 

 are dark blue after taking metlu'lene blue and brick \'el1()\\- after 

 ipecacuanha. 



Bile acids are recognized by Pettenkofer's reaction. 



Mix a little fiscal matter with a little sugar on a \\hite dish, add a 

 little HsSOj. A crimson colour indicates the presence of bile acids. 



To Estimate Nitrogen. 



Weigh a portion of fajcal material. 



Add 20 c.c. of ^^ H2SO4 to prevent loss of ammonia. 



Dry in a water bath. 



Complete desiccation in a drying chamber at 10° C. over H.SO,. 



Weigh out I grm. 



Mix with 25 c.c. of strong ILSOi and i grm. of sodiimi h\])(v 

 phosphate. 



Permit to stand four hours, then boil cautiously. 



The nitrogen now is converted and ammonium sulphate is formed. 



Allow to cool. 



Add 600 c.c. of water. 



Add sodium hydrate solution till strongly alkaline. 



Add a few pieces of granulated zinc to prevent bumping. 



Distill this, passing it into ^-^ H2SO4. 



Some of the acid is neutralized by the ammonia. 



Titrate the H0SO4 to estimate the amount of the ammonia distilled 

 over. 



To Estimate Fat. 



Dry faeces over H2SO4. 



Treat with i per cent, of HCl to split up the soaps. 



Add ether to dissolve fat. 



Add more ether and pour off and add to former. 



For bile pigments, bilirubin and biliverdin employ : — 



(i) Schmidt's reaction. 



Add to faeces a saturated solution of Hg perchloride. 



A bright green indicates their presence. 



