PRACTICAL APPLICATIONS 397 



properties, especially if the bacilli are injected into the veins 

 (Besredka). In preparing this serum it is a great advantage to 

 follow Besredka's process, and make use of sensitized bacilli. If 

 the unaltered bacilli are used the process presents some difficulties, 

 especially in the case of small animals. 



The serum thus prepared possesses powerful agglutinating and 

 bacteriolytic properties, and is extremely powerful as a prophylactic 

 agent. Kruse's serum protected a guinea-pig against a lethal 

 dose of the bacilli in doses of g^^ gramme, and T ^^OF c - c - f 

 Shiga's serum (activated with a suitable amount of complement) 

 would sterilize i c.c. of a twenty-four-hour broth culture of the 

 bacilli. 



Antidysentery serum has now fully proved its value in the 

 treatment of acute dysentery. According to Shiga, it reduces the 

 mortality of the disease by nearly 50 per cent. Kruse claims that 

 his serum causes a rapid diminution in the number of the stools, 

 such as is effected by no other agent, a general improvement in 

 the patient's condition, a shortening of the convalescence, and a 

 diminution of the mortality. Large doses, frequently repeated, 

 are required. 



It has probably a complex action, being at the same time 

 antitoxic and bacteriolytic, and contains opsonins and bacterio- 

 precipitins. 



In chronic cases it is of much less value, and in these forms 

 reliance must be placed on vaccine therapy. This has been care- 

 fully studied by Captain Forster and others. In Forster's patients 

 the mortality fell from 6-3 per cent, to 0*9 per cent., several cases 

 of the extremely chronic type which defies all ordinary treatment 

 for years being completely cured. He uses no opsonic control, 

 and standardizes his vaccines by determining the minimal lethal 

 dose ; this is necessary, since the various strains differ greatly in 

 toxicity. If the minimal lethal dose for a rabbit is about 0-4 c.c., 

 doses of o'i, 0*2, 03, and 0^4 c.c. are given at intervals of about ten 

 days. If symptoms of an overdose are produced, the amount given 

 at the next injection is reduced. 



Prophylactic treatment by injections of killed cultures, either 

 as they are or after autolysis or sensitization with an immune 

 serum, or injected in conjunction with immune serum, have been 

 used on a large scale by Shiga and others, with apparent good 

 results as far as the case mortality is concerned, though with less 

 obvious effect on the prevalence of the disease. This phenomenon 



