i8i6 



THE CHOLERAS 



flies and other insects. Care should be taken that good milk is 

 procured. No uncooked vegetables or salads should be used; fruit 

 must be sparingly indulged in, and unripe fruit, especially melons, 

 must be avoided. Balfour advises that jellies in particular should 

 not be used during a dangerous season. Weak tea and lime drinks 

 made with boiling water should be used as beverages. 



All cases of illness, but especially diarrhoea, must be promptly 

 treated by a medical man. 



With regard to prophylactics, eucalyptus oil in lo-minim doses 

 twice daily has been strongly recommended by some authors, but 

 the most usual prophylactic is a protective inoculation, which was 

 first introduced by Ferran in Spain, and has been studied and 

 improved by Haffkine and Gamaleia; by Tamancheff, who added 

 0'5 per cent, carbolic acid to the sterilized prophylactic; and by 

 Strong and others. 



Vaccines. — Haffkine originally used two prophylactics— a weak 

 and a strong — ^with the idea that the strong would produce too 

 violent a local reaction ; but this proving to be wrong, only the strong 

 is now used. This prophylactic is prepared by intensifying the 

 virulence of the vibrios by passing them through a series of rabbits, 

 and then growing on agar, from which the growth is washed off by 

 sterile broth which is made up to 8 c.c, of which one is injected 

 hypodermically into the flank as a dose. There is some local reac- 

 tion in the form of redness, swelling, and pain, and some general 

 febrile reaction. The result is that after an initial diminution of 

 the resistance against the disease this becomes considerably increased 

 after the fifth day. Haflkine's statistics show that it diminishes by 

 one-tenth the liability to the disease, and increases the chance of 

 surviving if attacked. Thus, according to Powell, in 6,549 

 vaccinated there were 198 cases and 124 deaths, and in 5,778 

 vaccinated there were 27 cases and 14 deaths. Vaccination 

 confers a partial immunity, which is said to last about fourteen 

 months, after which it diminishes, and finally disappears. Re- 

 vaccination is, therefore, necessary after this period. 



Strong's method is to spray agar which is contained in large flat- 

 sided flasks with a twenty-four-hour-old culture of the vibrio in broth, 

 and then to incubate the flasks at 37° C. for twenty hours, and to 

 suspend the subsequent growth in sterile water, which is first heated 

 to 60° C. for one to twenty-four hours, then incubated at 37° C. for 

 two to five days, and then filtered through a Reichel candle. Two 

 c.c. (the equivalent of 10,000 units of immunity in a rabbit) of the 

 filtrate, which must be sterile, are inoculated. This prophylactic, 

 which is said to be capable of being kept for a year, produces no 

 local reaction, and but slight general reaction, and increases the 

 bactericidal and agglutinative powers of the serum considerably. 

 Strong considers that it contains receptors separated from the 

 vibrios, and that it probably acts by increasing the bactericidal 

 and antitoxic powers of the epithehal cells of the mucosa of the 

 alimentary canal. 



