690 ABSORPTION. 



same was the case with two others. As a general rule, absorption ex- 

 hibited itself in those only whose epidermis was not in a state of integrity. 

 At the temperature of 74 Fahrenheit, however, the sublimate was oc- 

 casionally absorbed, but never the water. From other experiments, it 

 appeared evident, that the most irritating substances, and those most 

 disposed to combine with the epidermis, were partly absorbed, whilst 

 others were apparently not. Having weighed a drachm (seventy-two 

 grains, poids de marc) of calomel, and the same quantity of camboge, 

 scammony, salt of alembroth, and tartar emetic, M. Se'guin placed an 

 individual on his back, washed the skin of the abdomen carefully, and 

 applied to it these substances at some distance from each other, covering 

 each with a watch-glass, and maintaining the whole in situ by a linen 

 roller. The heat of the room was kept at 65. M. Se'guin remained 

 with the patient, in order that the substances should not be displaced: 

 and he protracted the experiment for ten hours and a quarter. The 

 glasses were then removed, and the substances carefully collected and 

 weighed. The calomel was reduced to 71J grains. The scammony 

 weighed 71| ; the camboge, 71; the salt of alembroth, 62 grains, 1 and 

 the tartar emetic 67 grains. 2 



It requires, then, in order that matters shall be absorbed by the skin, 

 that they shall be kept in contact with it, so as to penetrate its 

 pores, or the channels by which the cutaneous transpiration exudes; 

 or else that they shall be forced through the cuticle by friction, the 

 iatraleptic mode. In this way, the substance comes in contact with the 

 cutaneous vessels, and enters them probably by imbibition. Certain it 

 is, that mercury has been detected in the venous blood by Colson, 

 Christison, Cantu, Autenrieth, Zeller, Schubarth, and others. 3 



Not long after the period that M. Se'guin was engaged in his experi- 

 ments, Dr. Rousseau, 4 of Philadelphia, contested the existence of ab- 

 sorption through the epidermis, and attempted to show, in opposition 

 to the experiments we have detailed, that the pulmonary organs, and 

 not the skin, are the passages by which certain substances enter the 

 system. By cutting off all communication with the lungs, which he 

 effected by breathing through a tube communicating with the atmo- 

 sphere on the outside of the chamber, he found, that although the sur- 

 face of the body was bathed with the juice of garlic, or the spirit of 

 turpentine, none of the qualities of these fluids could be detected, either 

 in the urine, or the serum of the blood. From subsequent experiments, 

 performed by Dr. Rousseau, assisted by Dr. Samuel B. Smith, 5 and 

 many of which Professor Chapman 6 witnessed, the following results 

 were deduced. First, That of all the substances employed, madder and 

 rhubarb were those only that affected the urine, the latter of the two 

 more readily entering the system ; and secondly, that the power of ab- 

 sorption is limited to a very small portion of the surface of the body. 



1 Several pimples were excited on the part to which it was applied. 



2 Magendie's Precis, &c., ii. 262. 



3 The author's General Therapeutics and Materia Medica, 4th edit., i. 90, Philad., 1850. 



4 Experimental Dissert, on Absorption, Philad., 1800. 

 6 Philad, Medical Museum, i. 34, Philad., 1811. 



Elements of Therapeutics and Materia Medica, 6th edit., i. 65, Philad., 1831. 



