The departments (under which title are included about five hundred men employed by the commissaries of cattle, of provisions, and of stores, and by the quarter-master general) were, from beginning to end, more healthy and had fewer deaths than any one corps in the army. They lost none but from the plague; and, when this was discovered, such precautions were taken that the contagion was very speedily eradicated. The extraordinary health of this body of men, as well as their escape from the plague, though particularly exposed to the contagion, I could only attribute to the commissary of cattle, who had the greater part of them in his charge. Captain Burr was constantly among these men, and was most singularly attentive to every thing that regarded their internal economy. I am decidedly of opinion, that in the peculiar soil and climate of Egypt we are to look for the principal causes of the diseases which prevailed the most in that country. On grounds that appear not slight, we suspected that several of these diseases were propagated by contagion. But I have no intention of entering on the discussion of the theories of contagion; an obscure subject, and on which I do not presume to think that I could throw any new light. If ever the veil which covers it be removed, the late discoveries in chemistry bid fair to do it. The accurate knowledge which we have acquired of the composition of bodies, and in particular of the constituent parts of the atmosphere, have opened new fields of inquiry to the philosopher and to the physician. The successful application of these discoveries to the practice of physic by the Doctors Beddoes and Thornton, by Dr Rollo, Mr Cruickshank, Dr Wittman, and other eminent surgeons of the artillery, and more particularly by the philanthropic Mr Scott, of India, deserve the gratitude of the profession and of mankind at large. Hereafter, most probably, and when introduced into general practice, they will be looked upon as the greatest improvements that the healing art has received in modern days. In respect to the soil and climate of Egypt, as giving rise to disease, they are of considerable variety. In a country of such extent, stretching from the tropic, on the one side, to the shores of the Mediterranean, on the other, this might be expected. If, in Lower Egypt, and on the bleak shores of the Mediterranean, we saw the diseases of Europe, and met with the inflammatory diathesis; in Upper Egypt, and as we approached the tropic, we met with the same diseases, and succeeded with the same treatment, as in the peninsula of India. Perhaps no country is better known, or has been oftener described, than Egypt. I therefore presume that every thing regarding the climate and soil is generally known.