THE FAECES 409 



difficult to diagnose. An experienced examiner easily recognizes the four or eight 

 nucleated cysts when the material is mounted in Gram's iodine solution. 



When a smear preparation is desired, we may smear out a fragment of mucus 

 and stain by Romanowsky's or Gram's method. The character of the bacteria 

 present appears to be of diagnostic value especially in the case of infants and young 

 children. Beautiful preparations may be made by mixing the faeces with water, then 

 centrifuging for one minute. This throws down vegetable debris and crystals. Now 

 decant the supernatant fluid, which holds the bacteria in suspension, and add an 

 equal amount of alcohol. Again centrifuge, decant, and smear out and examine 

 the bacterial sediment. 



Simply taking a small mass of faeces and emulsifying it with a wooden 

 toothpick on a concave slide in 70% alcohol then, after the sedi- 

 ment settles, taking up a loopful with platinum loop from the surface 

 and smearing out, gives a very satisfactory smear. Gram's method, 

 with dilute carbol fuchsin counterstaining, gives the best picture. 



The Boas-Oppler bacillus may be found in the stools in this way. Normally, 

 a Gram-stained stool shows a great preponderance of Gram-negative bacilli and such 

 a finding in a measure excludes cancer of the stomach. Organisms which are Gram- 

 positive as well as the Boas-Oppler bacillus are, i. Lactic acid bacilli these show 

 Gram- negative areas in the slender bacilli. 2. A type of bacillus similar in size to the 

 colon bacillus but Gram-positive and noncultivable (found in acid stools). 3. Bacilli 

 of the B. subtilis type. 



It is very important to examine the faeces for T. B. With children a diagnosis 

 of tuberculosis may be made in this way when the sputum cannot be obtained, 

 the pulmonary secretion being swallowed. The preparation on the concave slide 

 as described above should be stained for T. B. Ulcerations in intestinal T. B. may 

 show very numerous bacilli. 



To culture for typhoid, dysentery, cholera, or other bacteria, take up the material 

 in a tube of sterile bouillion and smear it out with a swab over a lactose litmus agar 

 plate or an Endo or Conradi-Drigalski plate. Before streaking the plates they 

 should be very dry on the surface. This can be best done by pouring into a plate 

 with a circular piece of filter-paper in the lid and placing in the incubator for one-half 

 hour to dry. The filter-paper absorbs the moisture. Then inoculate the surface of 

 the plate with the faecal material. Selective cholera plating media are strongly 

 alkaline. 



In summer complaints of infants and children the organisms con- 

 cerned are as a rule related to various dysentery strains of bacilli. 

 Kendall in 293 stool examinations found the gas bacillus (B. Grog, 

 capsul.) in 22 cases. The gas bacillus produces intestinal disorders 

 which are not benefited by lactose but by buttermilk (lactic acid bac- 

 teria). For diagnosis, a loopful of the faeces is emulsified in a tube of 

 sterile milk or litmus milk. The emulsion is heated to 8oC. and held 

 at this temperature for twenty minutes. After incubation for eighteen 



