Tin.] SCIENTIFIC AND SANATORY LAWS. 191 



whether it is unwholesome or merely muddy ; it must 

 be good to know what spots are likely to be healthy, 

 and what unhealthy, for encamping. The two last 

 questions depend, doubtless, on meteorological as well 

 as geological accidents : but the answers to them will 

 be most surely found out by the scientific man, because 

 the facts connected with them are, like all other facts, 

 determined by natural laws. After what one has heard, 

 in past years, of barracks built in spots plainly pesti- 

 lential ; of soldiers encamped in ruined cities, reeking 

 with the dirt and poison of centuries; of but it is 

 not my place to find fault ; all I will say is, that the 

 wise and humane officer, when once his eyes are opened 

 to the practical value of physical science, will surely 

 try to acquaint himself somewhat with those laws of 

 drainage and of climate, geological, meteorological, 

 chemical, which influence, often with terrible sudden- 

 ness and fury, the health of whole armies. He will 

 not find it beyond his province to ascertain the amount 

 and period of rainfalls, the maxima of heat and of cold 

 wt his troops may have to endure, and many another 

 poLit, on which their health and efficiency nay, their 

 very life may depend, but which are now too exclu- 

 sively delegated to the doctor, to whose province they 

 do not really belong. For cure, I take the liberty of 

 believing, is the duty of the medical officer; prevention, 

 that of the military. 



Thus much I can say just now and there is much 

 more to be said on the practical uses of the study of 

 Natural History. But let me remind you, on the other 

 side, if Natural History will help you, you in return can 

 help her ; and would, I doubt not, help her and help 

 scientific men at home., if once you looked fairly 'and 



