220 Medical Topography of Upper Scinde. 



to be going on. We are not quite satisfied with his descrip- 

 tion of these rocks, but on this head we do not quarrel with 

 him. 



Dr. Kirk now begins to generalise and asserts — 1st, that 

 limestone rocks in volcanic districts produce fever all over 

 the world, and 2ndly, that localities on primitive formations 

 are not unhealthy. With regard to these propositions, it is 

 plain that their truth can only be established by the most 

 ample evidence, and in his attempt to prove those sweeping 

 generalizations our author appears to us most signally to fail : 

 further, granting his propositions — Sukkur does not, by his 

 own account, fulfil the required conditions — he adduces no 

 proof of unspent volcanic agency going on at present, and if 

 we can show this, it appears to us unnecessary to consider 

 the two laws which he has above laid down. 



What evidence is adduced of the presence of this volcanic 

 agency ? The occasional occurrence of sulphur in the rocks 

 in Scinde is brought forward as a proof. " I have in my 

 possession two specimens of sulphur from different parts of 

 Upper Scinde, and feel confident, that when the river is low 

 it may yet be found at Sukkur." Thus we see that where 

 its noxious agency is supposed to be so energetic, it is not 

 known to occur. The next argument is, " the well water at 

 Sukkur is strongly impregnated with sulphates, and the 

 sulphurous vapours arising from it are overpowering." This 

 may be so, but no one will affirm that sulphuretted springs 

 are not common in the oldest formations in which modern 

 volcanic action is unknown — nor will they admit that Har- 

 rowgate or Aix-la-Chapelle are nests of fever. In the very 

 last number of this Journal Dr. Murray happened to remark, 

 that in the jungly little valley where his sulphuretted springs 

 are given forth, and where we can state from our own expe- 

 rience that along the course of the stream the air is most 

 strongly impregnated with this gas, for at least a mile, fever 

 is, comparatively speaking, rare. 



