MICROBIAL DISEASES OF MAN AND DOMESTIC ANIMALS 851 



alone without the vaccination, Major Russell estimated that in 1913 there 

 was "only one one-hundred-and-sixty-seventh of the loss of time from 

 duty because of typhoid fever." 



Antityphoid inoculation was of inestimable value in the great war. 

 Exact figures cannot be given, but as an indication of what might have 

 occurred without it, the fact has been mentioned that a small portion 

 of the French army which in the early critical days had to be hurried 

 to the front without inoculation, developed as many cases of typhoid 

 fever as had occurred in the British army during the whole Boer war. 



ASIATIC CHOLERA* 

 Microspira comma 



The disease is endemic in parts of India whence epidemics have 

 spread throughout the world. America has been visited by several 

 epidemics and at the sea ports more frequently, chiefly New Orleans. 



The disease occurs naturally only in man. The incubation period 

 is from part of a day to ten days, usually about three days. 



In its most characteristic form the disease begins with few or no 

 prodromata. It is marked by fever, sudden onset of purging and 

 vomiting followed by cramps and severe depression. Evacuations 

 finally become almost a colorless liquid, "rice-water stools." The 

 cramps may occur in the whole muscular system most frequently in 

 the legs and are often extremely painful. A stage of complete collapse 

 finally occurs. There are, however, many variations from these 

 typical cases. The mortality is usually given at from 45 to 50 per 

 cent. 



After death there are found extensive acute degenerative changes in 

 the kidneys; the gastro-intestinal tract shows marked changes in the 

 lining membrane which may be necrotic, sodden and in some places 

 stripped away. 



The cholera vibrios may sometimes be seen in enormous numbers in smears from 

 typical stools. For a positive diagnosis, however, the organism must be cultivated. 

 The usual method is to inoculate a i per cent peptone solution from the stool, in- 

 cubating at 37 for from four to eight hours and sowing plates from the very surface 

 of the liquid, either of gelatin or alkaline agar or both. The vibrios are 3/i to 5/11 

 long by about o.^p. wide, and are curved slightly like a comma or sometimes in a 

 half circle. These comma forms are best seen in broth cultures. The ends 

 are usually rounded. In young cultures the organisms are usually arranged 



* Prepared by Edward Fidlar. 



