332 THE TUBERCLE BACILLUS 



to be eliminated therein for long periods." It is obvious from these experi- 

 ments that the vaccination of milch cows with living bacilli is undesirable. 

 Other experiments by this observer also seem to indicate that this method 

 of vaccination is not free from danger. In " seven out of eleven heifers 

 (ages 6-10 months) tubercle bacilli of various types which had been inocu- 

 lated in large doses into the sub-cutaneous tissues had found their way into 

 the milk sinuses of the undeveloped mamma " and in four cases at least 

 appeared to have undergone multiplication since their arrival there. There 

 is therefore reasonable probability that the first milk of some of these animals 

 would have contained living tubercle bacilli. 



[Immunization with living tubercle bacilli, whether human or bovine, is 

 therefore not free from risk.] 



Thomassen injected 2-3 eg. of fresh tubercle bacilli from an human source grown 

 on glycerin-potato into the jugular vein of calves ; as a rule, the animals were 

 resistent to a subsequent inoculation of bacilli of bovine origin but the animals 

 might succumb to the vaccinating inoculation and in those that recovered it was 

 possible that, the disease might subsequently recur. Thomassen preferred to give 

 increasing doses (1 mg. at the first inoculation, 10 mg. a month later and finally 

 20 mg.). The results were good but not constant. It was not uncommon to find 

 that in vaccinated animals which had failed to react to the test inoculation, the 

 bronchial glands, though normal in appearance when the animal was killed a few 

 weeks later, produced 'tuberculosis on inoculation into guinea-pigs. [Cobbett (for 

 the English Commission) found that human tubercle bacilli inoculated into calves 

 remained alive for prolonged periods, in lesions so minute as to be hardly visible.] 



Hutyra had good results with a similar method (inoculation of a recent 

 potato culture of tubercle bacilli of human origin). 



Baumgarten obtained very favourable results by simple sub-cutaneous 

 inoculation of human tubercle bacilli of standard virulence. According to 

 the author there was a non-specific, local, inflammatory lesion. 



(iii) Koch and others immunized calves by inoculating them with an 

 attenuated bacillus of bovine origin. The inoculations were made into the 

 jugular vein, 10 mg. on the first occasion and 25 mg. 3 weeks later. 



It did not appear to be a true vaccination but a more or less brief increase of 

 resistance to the action of the bovine type of bacillus. An heifer which had been 

 vaccinated did not react to the test inoculation and remained in apparent good 

 health but died 14 months later while suckling a calf. Lactation would appear to 

 re-awaken a latent infection (Pepere). 



[Pregnancy appears to render the sex-organs peculiarly susceptible to 

 tuberculosis. Cobbett (for the English Commission) records that three out of 

 six heifers inoculated when pregnant with bovine tubercle bacilli developed 

 tuberculosis of the uterus. In none of the three was the generalized disease 

 very acute, and in one (in which the mammary gland also was affected) there 

 was very little tuberculosis elsewhere. The non-pregnant uterus, he con- 

 tinues, has never been found affected in calves suffering from general tubercu- 

 losis however severe.] 



Klemperer endeavoured to treat persons suffering from tuberculosis by 

 inoculating them with tubercle bacilli of bovine type. He is said to have 

 noticed improvement in the condition of the patients but his experiments 

 are not conclusive. Similarly the inoculation of bacilli of the human type 

 into tuberculous cows appeared to have no curative action. 



(iv) Vallee succeeded in vaccinating cattle against the effects of the injec- 

 tion of tuberculin and in conferring some degree of immunity against living 

 cultures by inoculating them intra-venously with dead tubercle bacilli from 

 which the fat had been extracted. 





