86 CLINICAL MICROSCOPY AND DIAGNOSIS. 



1. Test for propeptones (or albumoses), by adding 

 to 5 cc. of the filtrate, a saturated solution of sodium 

 chloride, when any propeptone is precipitated. The 

 more turbid the fluid becomes, the greater the quantity 

 of propeptone. If no precipitate falls, a drop of acetic 

 acid (10% solution) may be added when, if present, 

 propeptone falls. This addition will only be required 

 in the absence of free acid. 



2. Test for peptones by adding to the filtrate, after 

 propeptones have been precipitated and filtered out, an 

 equal quantity of caustic soda solution and a few drops 

 of 1% solution of copper sulphate. A violet red or purp- 

 lish color (biuret) is produced, if peptone is present. 



(9) Starch should be so far changed in the gastric 

 contents as not to give either the reaction for starch or 

 for erythro-dextrin. Test for these, by adding to sev- 

 eral drops of the filtrate, a drop of tincture of iodine. 

 Starch, if present, will give a blue reaction, erythro- 

 dextrin, a purplish red. 



3. Microscopical examination. 



Portions of the unfiltered contents are examined 

 under the microscope, with the low and high lenses and 

 with the oil immersion lens. By this means we deter- 

 mine the nature of any food fragments, (starch granules, 

 milk and fat globules), the presence of blood, pus, 

 epithelium, and bacteria, including sarcinae and yeasts. 



Any fragments resembling portions of a new growth 

 may be sectioned and examined in the usual manner. 



Cultures may be made on the various laboratory 

 media to separate out and identify any bacteria present. 



