158 



to the Kirghese herds in the Government of Astrakan reports 

 (in the Archives of Veterinary Science) on the form of epizootic 

 diarrhoea known to Kirghiz camel owners as Tschak. This 

 is found in the valleys of the Caspian sea-board especially 

 m parts of Astrakan and is supposed to have developed only 

 within the last twenty years. In this time the character of the 

 sea-board land has changed from flats into quick-sands. Before 

 1870 only isolated cases occurred and those after heavy 

 rains followed by prolonged dryness when the stagnant rain 

 water collected into pools which if used for watering the animals 

 caused disease especially of the feeble and the young. Eank grass 

 growing after subsidence of the sea water driven up by the South 

 East winds in autumn also produces the disease. In 1881-82 the 

 epizootic and enzootic chai-acier of the affection was first noted. 

 In 1885 the disease raged violently sparing neither old nor young, 

 strong nor feeble. Sometimes the suckling young became affected 

 while the mother remained sound. In some instances whole 

 herds were swept off, in others deaths averaged 5 — 70 °/,. The 

 number affected and the recoveries varied in the case of different 

 owners. The several local outbreaks varied in fatality percentage. 

 Vedernikoff considers the disorder a severe gastro-intestinal 

 catarrh caused by eating food or drinking water strongly im- 

 pregnated with such sea salts as chlorine, sulphur, iodine, and 

 bromine compounds. Of these agents the chlorides (with which 

 Caspian water is highly impregnated) irritate the alimentary 

 mucous membrane, by absorbing liquids they increase peristalsis 

 and secretion of mucus and water, entering the blood the sodium 

 salt promotes formation of blood corpuscles but the potash salt 

 lessens this production, nitrogenous interchanges are preventedby 

 salt and digestion interfered with. The coagulability of the blood 

 is lessened and the blood pressure increased, whereby the pulse is 

 slowed, the heart's beat rendered irregular, the respiration less fre- 

 quent, and the body temperature lowered. Weakness, diminished 

 sensibility, and sluggish motions show the nervous system is in- 

 volved. The pancreas and kidneys are hyper-stimulated. The 

 sulphur compounds act like the chlorides but less markedly. The 

 brLiniidt's })roLluco more severe irrifatimi of rlie alimentary mucous 



