PROCEEDINGS OF THE MICROSCOPICAL SOCIETY OF LONDON. 157 



On the Organs that Secrete the Perspiration. A letter was read from 

 M. Giraldis, at the meeting of the Academy of Sciences, on the 16th 

 August, 1841, on the glands secreting perspiration. After mentioning 

 that they were first described by M. Breschet, in his pamphlet on the 

 skin, and enumerating the different German authors that have taken 

 notice of them in their workb, he proceeds to state the situations in 

 which they can best be seen. They are visible over all the skin, but are 

 most numerous in the following places, viz., the palms of the hands, the 

 soles of the feet, the armpits, and the mon veneris. They are not formed 

 by tubes which divide at their extremity, but by a narrow canal, which 

 penetrates the skin, and runs sometimes to a considerable distance in the 

 fatty tissue beneath. At the extremities of the fingers, they appear 

 entirely to cross it. They sometimes divide, but generally they are 

 rolled upon themselves, forming little masses, which have been taken for 

 the termination of the glandular structure. It is easy to see the tubes 

 forming these little masses on a piece of skin properly prepared. Such 

 is the kind of organ, according to M. Giraldis, in the human species, for 

 the secretion of the perspiration, and which is analogous to the elemen- 

 tary glands of insects. 



The general plan at present in use for examining the skin, viz., by 

 removing from it all the fatty tissue, is one which must always lead to 

 negative results, as the termination of the glands, always situated in 

 that tissue, must of course be removed ; another fatal mistake is the 

 employment of too thin sections of skin, as the tubes are thus com- 

 pletely cut, and it must be by the greatest chance, if we can preserve in 

 the same position the entire canal with its terminations. The skin 

 ought to be prepared in the following manner : The part should be 

 taken from the palm of the hand, or sole of the foot, along with the 

 fatty substance beneath it, and macerated for 24 hours in nitric acid 

 diluted with two parts of water ; it should then be removed, and mace- 

 rated for the same length of time in pure water ; a section of the thick- 

 ness of a millimetre, should then be made, and subjected to a slight 

 pressure between two plates of glass. The skin, thus prepared, becomes 

 transparent, and the prolongations which line the canals, of a yellowish 

 colour, thus making the tubes very distinct. By this way, we can ex- 

 amine the form of the papillae, and the tissue which composes them. 

 Abridged from the Gazette Medicale de Paris, Aug. 21, 1841, in Lond. 

 and E din. Month. Journ. Med. Soc., Nov. 1841. p. 823. 



PROCEEDINGS OF THE MICROSCOPICAL SOCIETY OF LONDON. 



May 26th, 1842. Professor Lindley, President, in the Chair. 



THE following communication, originally read before the Chemical So- 

 ciety on February 1st, 1842, was, at the request of the Council, laid 

 before the Microscopical Society, as being likely to attract the attention 

 of Microscopists to the field of Chemistry for research. 



" On the change of colour in the biniodide of Mercury." By ROBERT 

 WARINGTON, ESQ. The author after describing the method of prepa- 

 ration, and the well known change of colour which takes place when 



