392 The Philippine Journal of Science ms 



is difficult to explain, particularly in countries where the incidence 

 of infection in animals is very high. 



The habits and customs of coachmen in Manila, for example, 

 and the close housing of man and horses and other animals, give 

 the most favorable opportunities for the spread of the disease 

 to man. If there is a natural immunity in man against the infec- 

 tion, this immunity certainly has a very irregular distribution 

 and must be very strong in a large percentage of people, entirely 

 absent in a few, and of moderate degree in practically none. 

 Variation in virulence in the various strains of the bacillus does 

 not answer the question because the disease practically always 

 is fatal in horses, and, when man becomes infected, the disease 

 usually is a particularly virulent one and cases of mild infection 

 are almost unknown. 



Pathologically the most striking peculiarity of B. w,allei infec- 

 tion is the marked predilection of the organism for joints, 

 lymphatics, and cutaneous tissue. In practically every instance 

 there is a more or less extensive suppurative arthritis and sup- 

 purative lymphadenitis and a more or less extensive distribution 

 of suppurative skin lesions. 



Inflammatory areas and abscesses in other tissues and organs 

 of the body frequently develop toward the end of the disease, 

 but the principal and early and constant lesions are as above 

 mentioned. 



Symptoms. — The period of incubation is unkno\Mi. The onset 

 is similar to that of a number of severe acute infections ; usually, 

 it is rather sudden with chill or chilly sensations with fever and 

 indefinite aching pains. In some cases there is a prodromal 

 period of indefinite symptoms and a more gradual development of 

 fever. In still other cases the onset resembles that of pneumonia 

 very closely, and it may not be possible positively to diiferentiate 

 the two conditions until the absence of the expected consolidation 

 is noted. 



The fever usually runs a more or less irregularly remittent 

 course, varying from 38° to 40° or even 41° at times. 



The pain at first may be more or less general in character, 

 similar to that usually seen in dengue. More often, however, 

 from the first and in all cases after the disease is fully established 

 the pains localize in the joints — particularly the larger joints — as 

 the elbows, knees, ankles, etc. 



The joints rapidly become swollen and painful and the skin 

 glistening, as is seen in rheumatic fever. Still later, fluid accu- 

 mulates, and in the course of a few days suppuration is found 



