CHEMICAL NATURE OF SKIN SECRETIONS. 673 



1 to 12. Indigo is sometimes developed in sweat, 1 though whether from 

 indoxyl secreted, or as the result of the growth of chromogenic 

 micro-organisms, is not certain. 



The sweat of * the horse has heen studied by Leclerc 2 and Fred Smith. 3 

 This secretion normally contains proteids, a fact which may partly account for 

 the debilitating effects of profuse sweating in horses. 



Percentage Composition of Sweat of Horse (Fred Smith). 



Alkaline, sp. gr. 1020 ; Water, 94*3776 ; Organic solids, -5288 : Ash, 

 5-0936. 



Serum albumin .... '1049 



Serum globulin .... -3273 



Fat -0020 



Chlorine -3300 



Lime -0940 



Magnesia -2195 



Phosphoric acid .... Trace 



Sulphuric acid .... Trace 



Soda -8265 



Potash 1-2135 



Both Leclerc and Smith found urea in the sweat of the horse. 



The sweat of the hippopotamus contains a reddish-brown pigment not yet 

 identified. 4 



Buisine 5 has investigated the constituents of that part of the "sweat" of 

 sheep which is soluble in water. He found potash soaps of the fatty acids 

 from acetic to capric ; urea and ammonium carbonate ; potash salts of malic, 

 glycolic, pyrotartaric, oxalic, succinic, lactic, hippuric, benzoic, and uric acids ; 

 phenylsulphate of potassium, and traces of leucine and tyrosine. Malic acid 

 was previously only known as a vegetable product. 



Of the watery secretion of the skin of amphibians little is known. The 

 reaction of the secretion of the " mucous glands " is alkaline, while that of 

 the " granular glands," 6 chiefly found on the dorsal surface of the flanks 

 and legs, is acid. According to Ley dig, 7 acrid substances are secreted in 

 addition to mucin, in the case of the tree frog. In the case of the salamander 

 and toad, poisonous substances have been separated. 8 



Gratiolet and Cloez 9 state that the poisonous substance in the skin glands of 

 the toad and salamander is soluble in alcohol and of the nature of an alkaloid. 

 Yulpian 10 and more recently Phisalix and Bertrand n have investigated this 

 substance in the case of the toad. The symptoms of poisoning are paralysis 



1 Bizio, Sttzungsb. d. k. Akad. d. Wissensch., Wien, Bd. xxxix. S. 33 ; Hofmarm, 

 Wien. med. Wchnschr., 1873, S. 292 ; Bergmann, St. Petersb. med. Ztschr., 1868, 

 Bd. xiv. S. 28. 



2 Compt. rend. Acad. d. sc., Paris, 1888, tome cvii. p. 123. 



3 Jou.rn. PhysioL, Cambridge and London, 1890, vol. xi. p. 497. 



4 Weber, "Stud. ii. Saiigethiere, " Jena, 1886, S. 9. 



5 Compt. rend. Acad. d. sc., Paris, 1886, tome ciii. p. 66; 1887, tome civ. p. 1292; 

 and 1888, tome cvi. p. 1426. 



6 Hermann, Arch. f. d. ges. PhysioL, Bonn, 1878, Bd. xvii. S. 291. 



7 Arch. f. mikr. AnaL, Bonn, 1875, Bd. xii. S. 119; and Biol. Centralbl., Erlangen, 

 1892, Bd. xii. S. 458. 



8 Zalesky, Hoppe-Seyler's Med. -chem. Untersuch., Berlin, 1866, Bd. i. S. 85; Casali, 

 Jahresb. ii. d. Fortschr. d. Thier-Chem., Wiesbaden, 1873, S. 64 ; Fornara, ibid., 

 1877, S. 74. 



9 Compt. rend. Acad. d. sc., Paris, 1852, tome xxxiv. p. 729. 



10 Compt. rend. Soc. de biol., Paris, 1854, p. 135. 



11 Arch, de physiol. norm, et path., Paris, 1893, Ser. 5, tome v. p. 511. 



VOL. I. 43 



