Protective vaccinations 491 



orses treated for a long period with cultures of the plague bacillus 

 nd with the toxin of the same organism. Treatment is begun by 

 njecting plague coccobacilli killed by heat (70 C.). These injections 

 re made into the veins, with the object of avoiding the local lesions 

 ~hich are observed after the subcutaneous introduction of micro- 

 rganisms. When the horses have been rendered refractory by this 

 reatment with dead micro-organisms, the next step is to inject (also 

 ato the veins) small quantities of living cultures. The doses of these 

 ultures are gradually increased, and end by conferring upon the animal [514] 



very strong immunity, which is strengthened by injections of 

 roducts of cultures passed through a Chamberland filter. 



Calmette and Salimbeni 1 injected prophylactically more than 

 00 persons menaced by plague at Oporto. These comprised the 

 octors and the staffs of the laboratories of hygiene and of the 

 isinfection services, the firemen who removed the sick persons and 

 he dead, the families of those who were attacked, the members of 

 he French colony, etc. Into each person 5 c.c. of serum was injected 



ow the skin of the abdomen. These vaccinations in some cases 

 aused nettle-rash, eruptions similar to those so often observed after 

 he injection of the other kinds of serums. Of the total number in- 

 ected two persons contracted plague : the unfortunate Doctor Camera 

 Pestana and his assistant. The former succumbed to the disease, but 

 he second only contracted a very mild form of it. The study of 

 hese 600 cases, as well as of experiments on animals, demonstrated 

 hat the immunity conferred by the antiplague serum is set up 

 mmediately after its injection but is not of long duration. It is 

 >robable that it lasts for 8 or 10 days, or at furthest a fortnight only. 



Similar results were obtained at Glasgow. Van Ermengem 2 , who 

 las published a report on the epidemic in this town, mentions that 

 more than 70 persons in good health were inoculated with the serum ; 

 ?ach one received 10 c.c. beneath the skin of the belly. Of these 

 70 persons one was attacked with a fairly mild plague 8 days after 

 he vaccination, and another, a housekeeper, was attacked, 9 days after 

 he injection, with a congestion of the cervical glands induced by the 

 plague bacillus. Both cases recovered. All the other vaccinated 

 >ersons, in spite of constant exposure to the plague infection, 

 remained unaffected. Van Ermengem was of opinion that the two 



1 Ann. de VInst. Pasteur, Paris, 1899, t. xin, p. 902. 



2 Bull. Acad. roy. de med. de Belg., Bruxelles, 1900, 27 Octobre. 



