138 LABORATORY GUIDE IN BACTERIOLOGY 



c) Inoculate intravenously with 0.5 c.c. of a 24- 

 hour-old milk culture of B. welchii. 



d) After the culture has been distributed in the 

 circulation, which takes at the most 3 minutes, kill the 

 rabbit by a blow on the back of the neck. 



e) Put the rabbit in a warm place on top of the 

 thermostat for 18 hours, or from 6 to 8 hours inside of 

 the thermostat. 



/) After this time has elapsed, perform an autopsy. 

 Note the crackling, on pressure, over the axillary or 

 inguinal regions. The rabbit is swollen to a great 

 extent. Skin the animal, without opening the abdomi- 

 nal cavity; then quickly puncture the abdominal wall 

 and bring a flame to the opening. Note that the 

 escaping gas will burn with a blue flame. Also note 

 the disorganized condition of the liver, spleen, and 

 kidney. 



g) Make capsule stains from the heart's blood or 

 organs by Welch's method (modified). The modifica- 

 tion of Welch's method is as follows: Proceed in the 

 manner indicated on p. no, and, after washing the 

 acetic acid off with the stain (carbol fuchsin or gentian 

 violet), dry with filter paper and heat the specimen for 

 5 to 10 seconds before washing. Then proceed as be- 

 fore. 



7. Special study. Staining of spores of B. tetani 

 and B. edematis from 3-day-old glucose agar cultures 

 (see p. 128). 



8. Special study. Inoculation of a white mouse 

 or guinea-pig with B. tetani or its toxin (o.oi c.c.) in 

 the hind-leg or over the root of the tail (if a mouse). 

 Note daily the condition of the animal, and when dead 



