FAT IN THE F^CES 347 



Having familiarized one's self with the degree of digestion of muscle, starch, 

 and fat in a normal person, we are in a position to judge of the state of assimilation 

 in a patient. 



The first part of the test is the macroscopical one. For this grind up a faecal 

 mass of 1/2 to i inch diameter in a mortar, gradually adding water until it has the 

 consistence of a broth. About 1/2 c.c. of this emulsion should now be squeezed 

 out between two slides and studied against a dark surface and then when held up 

 to the light. The normal stool gives a rather uniform brownish homogeneous layer. 

 Connective-tissue remnants (indicative of gastric derangement) show as whitish 

 fibers. Undigested muscle tissue remnants as reddish-brown splotches. Fat 

 particles as whitish-yellow clumps. Potato remnants appear like sago grains and 

 mash out easily like mucus. Mucus is best noted in the fecal mass before making 

 the emulsion. In the microscopical test of this emulsion. 



We judge of muscle digestion by the intactness of the striations. 

 If a muscle remnant is only a homogeneous yellowish particle, it shows 

 satisfactory digestion. If it is rectangular, with well-defined cross 

 striations, it shows poor digestion for meat (Azotorrhcea). A loopful 

 of faeces should be smeared into a drop of Gram's solution for starch- 

 digestion determination. Normally there should be no blue-staining 

 starch granules. 



Soaps are gnarled bodies everted like the pinna of an ear, while soap crystals 

 are comparatively coarse and do not melt on application of gentle heat as do the more 

 delicate fatty acid crystals. Neutral fat is in round or irregular globules. The best 

 stain for fat is Sudan III (saturated solution of Sudan III in equal parts of 70% 

 alcohol and acetone). 



Mix up the fasces with dilute alcohol (50 to 70%) and then add a drop of the above 

 solution and apply a cover-glass quickly. The fat globules show as orange or 

 golden-yellow bodies. 



By rubbing up a small portion of the faeces in 36% acetic acid, applying a cover- 

 glass and heating over a flame until the preparation shows bubbles, we convert the 

 soaps and other fat combinations into free fatty acids which show as more or less 

 numerous highly refractile bodies which show a crystalline structure as the prepara- 

 tion cools. By practice one learns the amount of such globules to expect with differ- 

 ent fat contents in stools. 



Steatorrhoea, or the presence of fat in abnormal quantities in the 

 faeces, is shown by the pale, bulky, greasy stools as well as in the micro- 

 scropical examination. 



Average for normals in i gm. dried fasces: 



