OUTBREAK OF SURRA FEVER. 139 



In the plains of A.merica it has been noticed that in certain 

 thinly populated districts where fever was prevalent, the intro- 

 duction of railway tracks and the passage of trains has modified 

 the sanitary conditions. The theory in explanation of this fact 

 is that the displacement of air caused by the rapid passage of 

 the train creates a vacuum and consequent draught, and that a rush 

 of fresh air is in this way introduced. In other words, the train 

 produces a sort of artificial wind. The track of the G. I. P. Railway 

 passes immediately behind our Pauel premises, distant only 75 

 feet from the stables. About 2,000 feet further to the north the 

 Flats commence, and are crossed by the trains. In this memorandum 

 we are anxious to enumerate ail possible influences which may have 

 shared in the production of the recent outbreak of " surra." It is 

 perhaps worthy of consideration whether the Gr. I. P. Railway track, 

 which very shortly after leaving the marshy land of the Flats, passes 

 our Parel stables on their N.-W. side, does not act as an air-channel 

 from the one to the other. The line of horses standing next to the 

 railway was the line in which the " surra" was by far the most 

 prevalent. 



A conjecture has been put forward by some Veterinary 

 authorities in India that there is a connection between "surra" 

 and rats. A parasite has been found in the intestines of rats 

 which is similar to the parasite noticed in the blood of horses 

 suffering from " surra.' ' It is suggested that where rats have 

 access to grain, it becomes contaminated with their excreta, 

 and that when used for horses' feed the parasite may in that 

 way be conveyed into the horses" stomachs. In view of this 

 theory we think it right to mention that although the greater 

 portion of our grain is kept in paved godowns, and we do our 

 best to exclude rats, yet we know that both before and after 

 the grain is received by us rats do frequently get at it. But 

 before our grain is used for horses' feed it is carefully cleaned, 

 both by hand and through a machine. We ourselves cannot, 

 from our own observation, favour the rat-infection theory, If the 

 source of the disease is due to grain getting mixed with the exxreta 

 of rats, why is the appearance of the fever limited to certain seasons, 

 and why should it appear only in certain years ? For the past 

 14 years it has been unknown in our stables, and during those 

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