716 PATHOGENIC MICROOKG VNISMS 



site of the old latrines. Dysentery appeared among this particular 

 troop unit, whereas, other troops remained free. 



Preventive measures must center chiefly upon disinfection of 

 dejecta, closure of latrines, fly-proofing of latrines and kitchens, early 

 recognition of suspicious cases with appropriate measures and 

 enforced cleanliness of food handlers and of all men before and 

 after defecation. Care of water supplies and food supplies is of 

 course indicated. It is also important to inquire into the possibility 

 of recent intestinal disturbances however mild, among the kitchen 

 personnel and others in contact with food. It is not uncommon in 

 armies to find that company cooks are suffering from mild intestinal 

 disturbances to which they, themselves, have paid little attention, 

 but which may be sources of great danger to others. 



Prophylactic Vaccination. Many different methods of prophy- 

 lactic vaccination have been attempted. Early attempts were dis- 

 couraging because of the violent reactions obtained by the injection 

 of killed broth cultures or even killed suspensions of agar growths. 



Shiga 45 carried out vaccination experiments very largely because 

 he believed that the periodical appearance of epidemics in Japan- 

 indicated the acquisition of immunity by the community. He states, 

 for instance, that in the thirty years preceding 1908, two great 

 epidemics passed through Japan from the south to the north. The 

 epidemic remained in a single region from one to three years, rapidly 

 reaching a maximum and gradually declining. After a period vary- 

 ing from ten to twenty years, these great epidemics reappeared and 

 he believed that the interval could be explained by acquired im- 

 munity. Shiga's method consisted very largely in injecting, simul- 

 taneously, killed suspensions of agar cultures with specific serum (or 

 in other words, sensitized cultures), following this first injection with 

 killed agar suspensions without serum. This had the advantage, 

 which sensitized cultures always have, of not giving the severe 

 reactions which follow the injections of cultures alone. By these 

 methods he vaccinated 10,000 Japanese in epidemic regions without 

 very striking results as far as the morbidity is concerned, but with 

 considerable lowering of the mortality. 



Castellani inoculated 0.5 c.c. of a peptone water culture, killed 

 by heating to 55 for one hour, following this, after a week, with a 

 second inoculation of 1 c.c. Most observers have worked with killed 



45 Shiga, Cent, f . Bakt., Orig., 42, 1909, 132. 



