TYPHUS FEVER, TRENCH FEVER, ETC. 957 



provision for the circulation of air by proper vent holes will yield 

 good results. In the so-called " Canadian" type of hut the heat is 

 applied from below by digging a hole in the floor of the hut which 

 connects with the outside through a small tunnel, in which a furnace, 

 constructed in a variety of ways, can be placed, and a glowing coal 

 fire maintained. According to Bacot 53 and others it has been found 

 that nits protected by a single layer of khaki cloth are killed in 

 fifteen minutes at 52 C. The heat of such huts must be carefully 

 controlled, a matter which can be done either by thermometers or, 

 as advised by Bacot, by hanging in various places small tubes 

 containing paraffin or stearin, with a melting point of 60 or over. 

 Excellent methods of applying the various forms of disinfestation 

 by heat are those which were originated by Dr. Richard Strong 

 in Serbia, in which disinfestation trains with a shower bath car, 

 a steam sterilizing car made of a converted refrigerator truck, were 

 drawn by an engine, which supplied the steam for the disinfestors, 

 the hot water for the baths and the motor power. 



THE RICKETTSIA BODIES 



In 1910 during their work in Mexico, Ricketts and Wilder 

 observed small ovoid bacterium-like bodies in the intestinal canals 

 of lice which had fed on typhus cases. They described them as 

 showing polar staining, with slightly stained or entirely unstained 

 centers and as having the general appearance of very small 'bacilli. 

 Similar observations were made by Prowazek and by Sergent, Foley 

 and Vialatte in 1913, though the identity of the bodies seen by 

 these observers with those of Ricketts and Wilder was not, at first 

 clear. Most of the original observations were made on typhus 

 material, but subsequently Wolbach saw similar appearances in the 

 endothelial cells and vessel walls of animals infected with Rocky 

 Mountain Spotted Fever which he believed to be probably identical 

 with diplococcus-like structures described in the blood in the same 

 disease by Ricketts a few years earlier. Still later bodies of the 

 same general appearance were noticed in lice taken from Trench 

 Fever cases and in lice collected from the bodies of normal human 

 beings. The peculiar staining properties, frequently intracellular 

 position, minute size and pleomorphic structure of these peculiar 

 bodies suggested to many of these workers the possibility that they 



63 Bacot, Brit. Med. Jour., 2, 1917, 151. 



