686 SECRETION AND ABSORPTION B Y THE SKIN. 



if an arm or leg be used, since the combination of a body with water in 

 which it is soaked is accompanied by contraction, so that the total 

 volume after soakage is less than the sum of the initial volumes. 1 



Fleischer could obtain no positive evidence of absorption of water 

 by the skin of the arm, immersed in a Mosso's plethysmograph (pro- 

 vided with a capillary pipette) for three hours. 



Solutions of chemical substances easily detected in the secretions 

 have been much employed, a part of the body being immersed, or the 

 solution applied by means of a spray. Colouring matters, inorganic 

 salts, and drugs with marked physiological action, have been used. In 

 such experiments the chief points to be observed are (a) Integrity 

 of the epidermis before the experiment, and absence of destructive 

 chemical action by the substance usec? during its course ; (&) absolute 

 exclusion of possibility of absorption by the lungs in the case of a 

 volatile substance, or of a salt yielding a volatile substance under the 

 action of the sweat ; (c) the choice of substances capable of recognition 

 with certainty in minute quantities in the secretions. 



Braune,' 2 using foot baths of solutions of potassium iodide, iodine, 

 and hydriodic acid, with a layer of oil over the surface of the solution, 

 was unable to detect iodine in the secretions. Parisot, 3 using baths of 

 watery solutions of potassium iodide and ferrocyanide, belladonna, digi- 

 talis, and the colouring matter of rhubarb, repeated twice a day for 

 three to eight days, obtained no evidence of absorption. Hiifner 4 found 

 no lithium by the spectroscope in the urine after foot baths of lithium 

 chloride. V. Wittich 5 and Fleischer 6 were unable to confirm Eohrig's 7 

 statement, that aqueous solutions of potassium iodide are absorbed. 

 Winternitz 8 could get no evidence of absorption of 10 to 15 per cent, 

 solutions of lithium chloride in water, and results with cocaine were 

 negative. 9 



Again, Fubini and Pierini 10 could get no evidence of absorption of 

 the following solutions : Potassium ferrocyanide, 3 per cent. ; santo- 

 nate of soda, 2 per cent. : salicylate of soda, 5 per cent. ; potassium iodide, 

 5 per cent. ; and lithium benzoate, 2 per cent., all dissolved in water. 



Hence it is probably correct to conclude that watery solutions not 

 acting chemically upon the epidermis, and water itself, are not capable of 

 absorption by the intact skin of man. 



If we now turn to the case of fluids that can wet the skin, such as 

 chloroform, ether, alcohol, etc., we find that a certain amount of 

 evidence of absorption is obtainable in the case of man. 



Since chloroform, though an excellent fat solvent, causes pain and 

 blistering when long in contact with the skin of man, the experiments 

 have been mostly made with ether and alcohol. Ether is a better 

 solvent of fats than alcohol, and hence is more likely to give positive 

 results. Krause 11 maintained that both alcoholic and ethereal solutions 

 of salts are absorbed by the skin, but Fleischer, 12 using a volumetric 



1 Quincke, Arch. f. d. ges. Physiol., Bonn, 1870, Bd. iii. S. 332. 



2 Diss., Leipzig, 1856. 



3 Compt. rend. Soc. de blol., Paris, 1863, tome Ivii. p. 327. 



4 Ztschr. /. physiol. Chem., Strassburg, 1880, Bd. iv. S. 378. 



5 Hermann's "Handbuch," Leipzig, 1881, Bd. v. Th. 2, S. 257. 



6 Loc. tit. 7 " Die Physiologie der Haut," Berlin, 1876. 



8 Arch. f. exper. Path. u. PharmakoL, Leipzig, 1891, Bd. xxviii. S. 405. 



9 See also Soulier, " Traite" de tberapeutique et de pharmacologie, " 1891, tome i. p. 385. 



10 Arch. ital. de UoL, Turin, 1893, vol. xix. p. 357. 



11 Wagner's " Handworterbucb," 1844, Bd. ii. S. 174. 12 Loc. cit. 



