558 THE BACILLUS OF QUARTER ILL 



gives rise to trifling symptoms and confers a certain degree of immunity ; a 

 second inoculation 7 days later completes the immunization. 



On these facts Leclainche and Vallee have based the following method of 

 vaccination. 



Pure cultures are sown in Martin's broth and after incubating for 58 days are 

 distributed in glass ampoules, which are then sealed and heated in a water bath at 

 70 C. : this is the first vaccine. The second vaccine is prepared in a similar manner 

 but the ampoules are not heated. This method does away with all need for powdering 

 the vaccines and yields a vaccine of which the dosage is simple. 



Vaccination with these pure vaccines is hot unattended by danger, and in a later 

 paper Leclainche and Vallee recommend the administration of a dose of immunizing 

 serum as a condition precedent to the inoculation of the pure attenuated virus 

 (vide infra). 



Note. Animals vaccinated against quarter ill with pure vaccines are not 

 immune to malignant oedema (Leclainche and Vallee). 



Roux and Chamberland however had stated that guinea-pigs rendered immune 

 to quarter ill are often immune to the bacillus of malignant oedema, and Diinsch- 

 mann having obtained an antiserum for quarter ill affirmed that it neutralized 

 fatal doses of the bacillus of malignant oedema. These results were due to the fact 

 that the cultures used by the authors for preparing the immunizing vaccines were 

 impure ; they immunized the annuals against both infections at one and the same 

 time. 



3. Toxin. 



(i) Roux showed that broth cultures sterilized by filtration through porce- 

 lain or by heating at 115 C. contain slightly toxic soluble products which on 

 inoculation into animals produce a certain degree of immunity. He was 

 able to immunize guinea-pigs by inoculating them with a total quantity of 

 40 c.c. of the sterilized cultures administered on three separate occasions 

 at intervals of 2 days. 



(ii) Diinschmann obtained a toxin which killed guinea-pigs when given 

 intra-peritoneally in doses of 2 c.c. The bacillus was grown in meat pulp 

 (p. 566) for 7 days ; the fluid was then expressed, filtered through porcelain 

 and inspissated in vacua over sulphuric acid. 



(iii) Leclainche and Vallee have shown that the Bacillus chauvcei when 

 grown in Martin's broth produces a powerful toxin the inoculation of which 

 is not followed by any incubation period. The toxicity reaches its maxi- 

 mum about the fifth day of incubation and then diminishes. The decanted 

 fluid is so rapidly fatal to laboratory animals that the bacillus has not time 

 to develop. Three or four drops of such a culture inoculated into the 

 cerebral hemispheres of a guinea-pig lead to a fatal result in a few hours : a 

 dose of 2-5 c.c. inoculated into the ear vein of a rabbit kills the animal in 

 from 5 minutes to 5 hours : 10 c.c. injected into the jugular vein of a horse 

 is fatal in about 6 minutes. 



The toxicity diminishes in presence of air : free aeration destroys the toxin in 

 48 hours. The toxin is not completely destroyed by heating at 115 C., but by 

 heating at 70 or 75 C. its chemiotactic properties which before were negative 

 become positive. A large proportion of the toxin is held back on filtration, but the 

 filtrate is still fatal to experimental animals : guinea-pigs die a few hours after 

 the inoculation of 5 c.c. of the filtrate into the peritoneal cavity, and in smaller doses 

 symptoms of intoxication appear in 7-9 days and the animals die from cachexia. 



Eisenberg has confirmed Leclainche and Vallee's experiments. A six-day- 

 old culture in Martin's broth containing normal rabbit serum, after being 

 decanted and centrifuged, killed rabbits in a few minutes when 1 c.c. was 

 inoculated into a vein. This toxin is almost destroyed by heating at 60 C. 

 and is neutralized by the serum of a vaccinated rabbit. 



