But little is known concerning the sweat of the lower animals. Fourcroy analysed the white powder which hangs to the coat of the horse when sweat has dried upon it ; he de tected urea in that substance, but Anselmino could not. According to the latter chemist, the white matter is made up of the following constituents :— • • The animal matter possessed a green co lour in this case. Soluble in ether, but not in alcohol.
The perspiration in different forms of disease possesses a peculiar odour, and many very fanciful opinions have been given on this point. Scabies is said to afford a mouldy odour; jaundice is musky, and syphilis sweet. In ague, the odour of fresh-baked brown bread is said to pass from the skin. Stark states that the quantity of lactic acid is increased in the sweat in scrofula, rhachitis, and some cutaneous eruptions.
Prout noticed an increase in the quantity of salts in sweat in a case of dropsy. An excess of salts has also been noticed by An selmino in a severe case of gout. It has been said that in cases of gouty and urinary con cretions the quantity of phosphate of lime is increased. As regards the latter form of dis ease, there is no good reason to believe the opinion above stated to be true.
A great increase of lactic acid is observed in cases of rheumatism and gout ; the sweat in such cases is always extremely acid. An selmino, however, states, that V he has ob served the sweat after a gouty attack has passed off, containing a large proportion of ammonia. Anselmino and Stark state that they have detected albumen in sweat ; the former in rheumatic fever, the latter in gas tric, putrid, and hectic diseases, and in cases generally immediately before death. Simon could not detect it in sweat which he obtained from the breast of a person suffering from phthisis in the colliquative stage.
Fat is also said to be found in large quan tity in colliquative sweats. Bilin and Mary
colouring matter, or biliphmin, have been found in the sweat of icteric persons. Berend says he has observed it in bilious fevers.
Voigtel states, that he observed blood to sweat from under the arm of a young man after violent exertion. Such perspiration is also said to have been observed in scurvy and low typhus fever. Uric acid has been found in the sweat of gouty patients, probably in the form of iirate of soda.
Landerer observed a red-coloured sweat in a fever patient's axilla, which he believes to have contained the red colouring matter of the urine (uroerythrin). Blue perspira tion has been noticed by several writers. Dr. Bleifuss noticed it coming from the foot of a patient suffering from abdominal disease. Michel noticed it in hysteria and hypochon driasis. Sugar has been detected in the per spiration of persons affected with diabetes, by Nesse. Various substances used internally as medicines, as articles of diet, or taken for the purpose of experiment, have been recog nised in the sweat. These are, according to Stark, sulphur, mercury, iodine, iodide of po tassium, assafcetida, garlic, saffron, olive oil, rhubarb, indigo, Prussian blue, and copper.
Landerer observed, that if he took quina his sweat became bitter.
In cases of Morbus Brightii I have been able more than once to detect urea in the perspiration, and I am inclined to believe it constantly present both in cases of suppres sion and retention of urine.
I have stated that experiments lately made by Landerer, the Athenian chemist, have proved urea to exist in the sweat in health. If this be proved, we of course can no longer regard it as an abnormal constituent of that.
fluid, but must look upon it merely as present in excess in the diseases above alluded to.
(G. Owen Rees.)