LOWER MAMMALS. 689 
cases as analogous. The skin of the mammals usually employed for such 
experiments is thinner than that of man, less horny, more vascular on 
account of the hair, and in some cases (rabbit) possessed of hair follicles 
with wide mouths. The presence of hair is a source of trouble in experi- 
ment, for, if not shaved, excoriations may be passed over, while, on the 
other hand, the process of shaving is apt to be accompanied by slight 
injuries to the surface. 
As with man, so here there is little positive evidence of absorption of 
watery solutions, and one is inclined to attribute the results of those 
observers who maintain that watery solutions are absorbed, to injuries 
produced in shaving, or clipping, or accidental introduction by mouth or 
lungs. 
Forlanini 1 maintained that rabbits could be poisoned by painting 
aqueous solutions of strychnia, acidulated with acetic acid, on the skin, 
but v. Wittich 2 could not get the effect on white rats, nor Fubini and 
Pierini 3 with guinea-pigs, while Winternitz i obtained both positive and 
negative results with live rabbits. Fubini and Pierini allowed the tails 
of rats to soak in strychnia and potassium cyanide solutions (for forty 
minutes in the former case and two hours in the latter) without effect. 
Traube-Mengarini 5 painted the skin of dogs daily for two months 
with aqueous solution of potassium ferrocyanide, killed the animals, and 
treated skin sections with ferric chloride. The blue was only found 
between the surface cells, not reaching deeper than the stratum granu- 
losum. Acidified borax-carmine solution, applied daily for seventy days, 
gave a like result. Fleischer 6 got iodine through the belly skin of a 
rabbit (into a watch-glass of water introduced under the skin) in two 
hours from a cylinder full of the tincture, but admits that the structure 
of the skin was altered. 
With ether and chloroform solutions, absorption is more marked 
in the thin skin of the rabbit, guinea-pig, and rat, than in that of man. 
Waller 7 immersed the leg of a guinea-pig in a mixture of chloroform 
and tincture of aconite, and was able to poison the animal, an effect not 
produced by the tincture alone. White rats with the foot in a chloro- 
form solution of atropine, exhibited a dilated pupil in two or three 
minutes ; with the tail (thicker skin) immersed, not till half an hour 
had elapsed. Strychnia in the same way he found was absorbed from 
solutions in chloroform, but not from those in alcohol. 
Winternitz s also found that rabbits absorb strychnia solution in 
chloroform, and points out that this is not merely an effect of " stimu- 
lation," because a previous treatment of the skin with mustard or 
ammonia does not hasten the intoxication. 
Winternitz has also pointed out that cleansing the skin of rabbits 
with ether or chloroform allows absorption of aqueous strychnia solution 
to take place, and, microscopically, it is found that silver nitrate solution 
penetrates more deeply if the skin is so treated. Alcoholic washing of 
the skin also tends to make subsequent absorption of aqueous solution 
possible, but to a far slighter degree than in the case of chloroform and 
ether. 
1 Ann. univ. di med. e chzr., Milano, 1868, vol. ccv. p. 473. 
2 Loc. cit. 3 Loc. cit. 4 Loc. cit. 
5 Arch. f. Physiol., Leipzig, 1892, Supp., S. 1; Arch. ital. de biol, Turin, 1891, 
vol. xvi. p. 159. 
6 Loc. cit. 7 Proc. Roy. 80c. London, I860, vol. x. p. 122. 8 Loc. cit. 
VOL. I. — 44 
