ACID INTOXICATION IN ASIATIC CHOLERA. 71 



The injections were made intramuscularly at intervals of about two weeks 

 over a period of four and a half months. Determinations were made of 

 the protective power of the serum for guinea pigs against intraperitoneal in- 

 oculation of the vibrio emulsion killed with sodium hydroxide. The serum was 

 tested before the injections were begun and at the end of the period of immuniza- 

 tion, but no definite increase in this protective power could be detected. Three 

 to 5 cubic centimeters of horse serum, either before or after treatment of the 

 animal, when digested for thirty minutes with the minimal lethal dose of the 

 cholera suspension (usually 1 to 2 cubic centimeters for intraperitoneal injec- 

 tion) were sufficient to completely protect guinea pigs of 300 grams. Sera of 

 much higher efficiency have been obtained, notably that of Salimbeni(12) 0.002 

 cubic centimeter of which neutralized twice the lethal dose of cholera toxin. 

 The behavior of the horse itself showed little evidence of immunity. The sub- 

 cutaneous injections produced a local swelling and some rise in temperature. As 

 the injections were continued there was only a slight diminution in this reaction. 

 Finally, the minimal lethal dose by intravenous injection of the killed cholera 

 material was determined upon normal horses. Three months after the last sub- 

 cutaneous injection and after the horse had been under treatment for nine months, 

 the intravenous injection of the minimal lethal dose, al^put 4 cubic centimeters, 

 produced a fatal result in twelve hours, , 



The serum was used intravenously in 300 cubic centimeter quantities 

 in 1 to 10 dilution in 0.5 per cent sodium bicarbonate solution. No more 

 than two injections were made in any given case ; therefore the maximum 

 amount of the anticholera serum for any patient was 400 cubic centi- 

 meters. Favorable results have been reported with larger amounts, 

 such as 1,040 to 1,390 cubic centimeters. (10) A very limited number 

 of cases were treated with serum. Only those patients were selected 

 in which the general symptoms were severe and the state of collapse 

 was extreme. Six of these cases in the bicarbonate series were of this 

 type. Two died in collapse without any definite response to the injec- 

 tions. The four remaining recovered, but without any pronounced dif- 

 ferences from extreme cases which recover imder sodium chloride 

 treatment. However, the recovery of four of these six patients was 

 unexpected and a control series with normal serum seemed advisable, 

 but practically no cases were available. Only one patient was tested. 

 He was admitted in complete collapse, and the toxaemia, though well 

 marked, was not extreme. In all 600 cubic centimeters of normal 

 horse serum were injected and a total of 12 liters of fluid. There was 

 only a slight response to the injections. On the third day there were 

 three moderately large hsemorrhages from the bowel, and death oc- 

 curred on the fourth day. 



Autopsy showed extensive oedema of the left lung with adhesions bf the 

 pleura. Multiple haemorrhagic infiltrations extending to the serous coat were 

 found in the small intestine. These areas measured about 1 centimeter in 

 diameter; they were most numerous just above the ileo caeeal valve and grad- 

 ually disappeared in the upper fourth of the intestine. 



