TYPHUS FEVER IN INDOCHINA. 135 



III. 



The diagnosis of the cases which have been cited was not immediately 

 apparent. We had already observed some cases of spirillar fever among 

 our Tonquinese patients, and therefore we thought ourselves justified in 

 the supposition that we were again dealing with spirillar fever, presenting 

 modified. symptoms in the natives of south Annam. However, we hesi- 

 tated to attribute a new disease, which had never previously been noticed, 

 to the spirilla. The evidence soon became so positive that we were 

 induced to think of typhus fever. 



It is true, the eruption was wanting, and we tried in vain to obtain 

 it in the experimental disease. Although failing in this, we succeeded in 

 reproducing a peculiar, cyclic fever, a well-defined disease which corre- 

 sponded exactly with the description of typhus fever. Although the 

 actual exanthem failed in our cases, it is reasonable to suppose that the 

 congested condition of the conjunctiva? was in a way a substitute. 



This is the first time this disease has been described among the An- 

 namese. Is it not possible that it has previously escaped observation 

 because of the absence of an eruption? We know that in sporadic 

 cases and in light ones the eruption generally fails. There have been 

 epidemics without eruption (Dieulafoy), and all writers are agreed in 

 pointing out eases without eruption in the most marked epidemics. 

 Netter observes that "the eruptions in typhus fever are not constant ; their 

 absence is noted in a tenth or twentieth of all cases. These facts are not 

 uncommon in the history of eruptive fevers. Dengue, for instance, 

 causes epidemics where eruptions do not appear. 



A diagnosis might also be made by elimination, after having reviewed 

 the diseases which resemble typhus fever most closely. 



The absence of Laveran's hsematozoa from the peripheral blood and the 

 spleen, the complete inefficacy of quinine, and the characteristic of the 

 chart, permit us to set aside malaria. 



The points of comparison with typhoid fever are very vague, but the 

 differences are sharply accentuated. It is true that the tongue was 

 coated, but it had not the dry and "roasted" appearance of that of typhoid 

 fever; neither were there any intestinal phenomena, but on the contrary 

 constipation. The abrupt start, the course of the chart and the crisis, 

 differentiate our cases from typhoid or paratyphoid fevers. 



Spirillar fever would not have passed unperceived at Nhatrang, where 

 it had just been studied for the first time in Indo-China. This fever 

 gives a chart with oscillations and relapses very different from that 

 presented by the disease under discussion ; besides, an examination of the 

 blood settles the question. 



Kala-Azar is too well known to-day to be confused with this disease. 



