500 W. Whitaker — On Geology and Consumption. 



that affect the saturation of the subsoil had not also some connection 

 with consumption ; or in other words, whether places on those 

 geological formations that allowed the free drainage of water would 

 not have a lower consumption death-rate than places on less pervious 

 or damper beds. 



Dr. Buchanan having been commissioned to undertake a further 

 enquiry, with the object of bringing new facts of this kind into evi- 

 dence, application for the needful geological data was made by the 

 Medical Officer of the Privy Council to the Director- General of the 

 Geological Survey, and of course all the information in the posses- 

 sion of the Survey was placed at Dr. Buchanan's disposal. 



After a little consideration we saw that it would be useless to take 

 up for examination any district in which the surface-deposits of 

 gravel, etc., had not been mapped, as well as the regular formations ; 

 and also that it would not do to take small areas scattered here and 

 there about the kingdom : one large connected tract was essential for 

 any trustworthy result. This at once limited the range of the 

 enquiry to the South-East of England ; for only in the counties of 

 Kent, Surrey, and Sussex (or part thereof), had the Geological 

 Survey mapped those surface-deposits (with some exceptions of no 

 great importance here). There are other tracts — as in Lancashire — ■ 

 where the drift has been mapped, but they are of much smaller 

 extent. This limitation having been made, I was instructed to give 

 Dr. Buchanan all the help in my power, and consequently I worked 

 with him for some little time, referring to my colleagues for informa- 

 tion as to districts that were out of my own personal knowledge. 



Luckily for the enquiry the aforesaid three counties have other 

 recommendations. They are without any great manufacturing 

 industry ; and the conditions of life in factories had been proved, by 

 previous investigations, to have an influence of their own upon the 

 disease in question : they have great variety of soil, and yet their 

 geological formations have, for the most part, a continuous outcrop, 

 and often take up broad tracts ; and they have many different 

 conditions of surface, but without the level of the ground being 

 subject to too abrupt changes, such as would be found in mountainous 

 districts. 



The metropolitan parts of Kent and Surrey had of course to be 

 left out of consideration, as it would be quite hopeless to investigate 

 a place like London, in which there are so many disturbing causes, 

 such as the presence of large hospitals and the exceptional industrial 

 conditions of the population. 



It is needless for me to enter here into the purely statistical part 

 of the enquiry, or the various allowances that had to be made for the 

 influence of public institutions ; for the influx of visitors to places 

 supposed to be good for consumption ; for wrong returns of the 

 causes of death, &c. ; enough to say that all these things were care- 

 fully taken into account by Dr. Buchanan. 



The geological part of the enquiry was two-fold, embracing in the 

 first place the consideration of the composition and character of the 



