512 THE RECOIL OF MAN'S INFLUENCE 



pupae develop beneath the surface, until such time as the 

 fully formed pupa comes to rest at the surface, and from 

 its split skin the winged Mosquito flies into the air, ready, if 

 it be a female, to do its worst to the race of men. 



Look again at the Scottish records of ague in the light 

 of the discoveries of Grassi and Laveran, Manson and Ross. 

 Where did it most prevail ? In the low-lying and marshy 

 counties bordering the east coast and the Solway,or along the 

 lines of the great rivers, where spring and autumn floods left 

 abundance of stagnant pools ; and especially in the Carse 

 of Gowrie, still characterized by its warm humidity : that is 

 to say in just those areas where in the days of unreclaimed 

 marsh we should have expected to find Mosquitoes. It was 

 less common apparently north of the Grampian Hills ; but 

 Mosquitoes prefer warmth, and the lower temperature of the 

 northern counties may have been just sufficient to have 

 checked the profusion of multiplication which seems to be 

 necessary for the effective spread of malaria. We know that 

 at the present day, Anopheline Mosquitoes still live in 

 Aberdeenshire, Inverness-shire and as far north as Suther- 

 land, but their numbers are small. 



Whom did ague attack ? There is scarcely a reference 

 to the upper or artisan classes having suffered, and again 

 and again the farm labourer is singled out for notice on 

 account of his susceptibility to the distemper just the very 

 man whose work in the fields laid him open to the attentions 

 of the mosquito amazon. 



Last link in the chain : In the latter part of the eighteenth 

 century in Scotland agriculture made great strides forward : 

 regular systems of cropping began to replace the primitive 

 and wasteful ways of the "outfields," and the "infields," and 

 the success of the use of marl arid lime upon peaty soils led 

 to the reclamation of much marsh and bog-land and to the 

 thorough draining by closed conduits or open ditches of land 

 which previously had lain sodden with moisture throughout 

 most of the year. It never entered man's mind that, by the 

 way, he was destroying Mosquitoes, since he was destroying 

 their breeding-places ; he probably never noticed, as the 

 years passed, that he had less often to stop to revenge the 

 prick of the Gnat. Yet unwittingly he had set in motion a 

 chain of circumstances which was to circle and wheel till it 



