64 Dr. Mac CuUoch on Malaria on Ship-hoard, 



obstruction in the chain cable, while others of the crew, un- 

 avoidably employed on deck, also died in a few hours of 

 the same disease ; the attack having attended, in an instant, 

 the first perception of the land smell. And if this is an ex- 

 treme case, it is precisely the one required as a proof of the 

 truth and value of these remarks. In ordinary circumstances, 

 the disease would have been a fever; but coming on less de- 

 cidedly, and easily attributed to other causes, the same reason- 

 ing would not have been deduced from it. And if the mere 

 delay of a few minutes in this case, arising from the accident 

 to the cable, was, in the captain's own estimation, the cause of 

 this loss, I must also remark, that the vessel was then about 

 five miles from the shore. How much Blane and others have 

 erred, and how dangerously, in fixing on one thousand, and 

 on three thousand yards, as the utmost limit of the range of 

 malaria in these cases, I need not say. 



The other circumstances in which ships and their crews are 

 exposed to the malaria of the shore, are more familiar and 

 admitted; however much the necessary precautions are for 

 ever neglected. I can afford to be comparatively brief, there- 

 fore, on these ; and their enumeration will complete all that is 

 necessary as to the first leading cause of fevers, or of marsh 

 fevers, in ships. 



The general cause of evil in this case, is familiarity with the 

 shore ; the landing of men, mider whatever circumstances, in 

 situations where malaria exists. The danger is evidently greater 

 as the harbour or anchorage is most exposed to the effluvia of 

 marshes or jungles ; but I need not here repeat circumstances 

 which were pointed out in the former essay. That it is also 

 greatest at night, or between sunset and sunrise, has been 

 further shown ; so that, on both these considerations, addi- 

 tional precautions ought to be founded. And it has so hap- 

 pened, in general, from obvious enough causes, that most of the 

 tropical towns and harbours are situated in the most unhealthy 

 spots : while, not seldom, a bad one has been chosen where a 

 salubrious one was equally convenient, or, as in the case of 

 Batavia, artificial means have, by their adoption, rendered that 

 which was naturally bad still worse. And the same indeed is 

 too often true, even in Europe, as in the Mediterranean : the 



