The increase in population, large as it has been under Russian rule, would have been still greater but for the prevalence of intermittent fever. That this scourge is connected with irrigation is beyond doubt, for the western districts, where water is scarce, are comparatively free from it; while in Tajand 30, and in Merv 85, per cent. of the applications for medical relief were due to intermittent fevers.[666] The conditions prevailing in the irrigated tracts are precisely the same as those in Central Bengal, which is in process of being slowly depopulated by malarial fevers. In both countries we have a waterlogged subsoil, due in the one case to excessive rainfall and inundations from the rivers; in the other, to the presence of a network of irrigating channels. The lesson to be learnt by administrators of both provinces is the necessity of providing drainage. Smallpox was as fatal in Transcaspia as malarial fever. Epidemics recurred almost annually, and 50 per cent. of the children were slain or disfigured by the pest. One of the first steps taken by the Russians was to introduce vaccination. They encountered a vast amount of prejudice, especially among the priesthood, but the value of the boon conferred on suffering humanity by Jenner has long been recognised. Vaccination is decidedly popular, and as a consequence smallpox is almost unknown.[667] Enteric fever, which is increasing in an alarming ratio in Indian garrisons, is rare in Transcaspian cantonments, and unknown elsewhere in that province. Epidemics of cholera are also uncommon. The last took place in 1892, when the infection was introduced from India by way of Herāt. It ravaged Meshed, the capital of Khorāsān, in May, and reached Askabad on the 1st June, having travelled 100 miles in eighteen days; thence it followed the line of rail, causing a mortality of 1859 out of 3471 attacks. The health of the Russian troops in Central Asia is, as might be expected, less satisfactory than that of the civil population. The annual admissions to hospital during the six years ending with 1895 were no less than 705 per mille; the deaths, 12.5; while 20.2 were discharged as unfit for further service. Thus the loss by death and incurable disease to the Russian army serving in Transcaspia exceeds 3 per cent. annually.