VOL. LXXItl.] PHILOSOPHICAL TRANSACTIONS. 345 



causes a white precipitate in the nitrous solution of cobalt, but the liquor still 

 continues red. 



With regard to the marine acid, copper precipitates the regulus, but volatile 

 alkalis do not strike a blue with this solution ; which shows that the copper unites 

 with the arsenic. Iron also precipitates the arsenic. Tin is soluble in marine 

 solution of arsenic ; but I could observe no precipitate, nor does regulus of ar- 

 senic precipitate tin. Neither bismuth nor the regulus of arsenic precipitate 

 each other from the marine acid in l6 hours. Regulus of antimony is also 

 acted on by the marine solution of arsenic, though it causes no precipitate, nor 

 does the regulus of arsenic precipitate it. 



IV. On a Species of Sarcocele of a most astonishing Size in a Black Man in the 



Island of Senegal ; with some Account of its being an endemial Disease in the 



Country of Ga/am. By J. P. Schotte, M. D. p. 85. 



There are certain diseases which are peculiar to certain countries only, and are 

 thence called endemial ones of such particular countries where they occur. The 

 more progress we make in the discoveries of countries, the more we are con- 

 vinced of this fact, and the greater is the number of those diseases that become 

 known. Their formation may depend on climate, food, water, hereditary dis- 

 position, and other causes. Many endemial diseases of the most distant coun- 

 tries have been described by ingenious travellers ; but as the Europeans have not 

 yet penetrated into the interior parts of many countries, it is probable, that there 

 may be several more of this kind, entirely unknown to us. A disease of this 

 class, which I have seen at Senegal (says Dr. S.) and which, as far as I know, 

 has not yet been mentioned by any author, convinces me of what I have ad- 

 vanced ; and as it is a remarkable one, I think a short description of it may not 

 be unacceptable to the curious in physic. 



Mr. Bishopp, surgeon in chief of the province of Senegambia (who now re- 

 sides in London) telling me one day, that he was going to see a poor black man 

 of the Bambara nation, afflicted with a most extraordinary and dreadful disease 

 in his testicles, I accompanied him, being glad of the opportunity of seeing it. 

 We entered the hut, and saw the man lying on a negro-bed, elevated about a 

 foot from the ground. He said to Mr. Bishopp, that there was again an ulcer 

 on his scrotum, which had made him take the liberty to request his attendance. 

 I looked at the scrotum, and found it of an astonishing size ; but the place 

 where he lay being dark, the hut having no windows, and those people having 

 no candles, he was asked, if he could not walk towards the door, that we might 

 see better. He answered, that he would try ; but this was attended with much 

 difficulty. A long cotton sheet was first spread on the ground before the bed, 

 which being done, he took, with both his hands, the enormous scrotum, moved 



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