1134 



BACTERIOLOGICAL METHODS 



Fig. 43. — Tubercle ba- 

 cillus slant culture on glyc- 

 erin-agar, several months 

 old. — (Siilt, after Curtis.) 



is not conclusive, the other two inocu- 

 lated guinea-pigs should be kept 2 weeks 

 longer then dissected and examined like 

 the first. Occasionally there is abscess 

 formation at the point of inoculation but 

 this need not necessarily interfere with the 

 tubercular development in the glands and 

 in the deeper tissues. 



It is frequently possible to isolate the 

 bacillus of tuberculosis (from sputum, 

 glandular tissues, meat pulp, centrifugal- 

 ized sediments of milk, cream, etc.) by 

 special manipulation and the use of special 

 culture media. The following method 

 is suggested. Spread two or three drops 

 of the material (concentrate, sediment, 

 crushed, suspected tuberculous meat ex- 

 tract, etc.) evenly over the surface of two 

 or three glass slips and place the smear 

 preparations in the drying oven at 100° C. 

 for 15 min., however, not before the ma- 

 terial on the slips is well dried at the room 

 temperature. Tubercle bacilli are quite 

 resistant to dry heat and will withstand 

 the temperature of 100° C. for from 30 

 min. to I hr. The exposure to that tem- 

 perature for 15 min. will kill most of the 

 bacteria associated with the tubercle germs 

 and will in fact kill some of these. At 

 the end of 15 min. take the glass slips 

 from the drying oven and by means of a 

 small sterile spatula or scalpel, scrape the 

 dried suspected material over the surface 



