IN RELATION TO EVAPORATION. 117 



In the majority of the experiments described, the cutis was removed with the 

 cuticle. . The results might appear more satisfactory if the cuticle alone had been 

 abstracted — this a difficult matter, so difficult, that I rarely attempted it — but, 

 inasmuch as the cutis does not seem to exercise any limiting power on evapora- 

 tion, may it not be regarded as inoperative or impassive, and to have no material 

 vitiating effect on the results ? 



Viewing the function of the cuticle physiologically, must it not be considered 

 as intimately connected with animal heat ? Thus, where its retentive, moderat- 

 ing power is lowest, as in the instance of the batrachians, is it not operative in 

 preserving these comparatively cold-blooded animals cool ; and vice versa in the 

 instances in which its power is highest, in birds, is it not conducive to the pre- 

 servation of the elevated temperature for which they are remarkable ? 



A more important function, it may be inferred, is performed by it, associated 

 with the preceding, namely, of preventing a too rapid loss of water from the 

 system, and especially from the blood, thus preserving this vital fluid of a proper 

 degree of dilution, and the solid parts of a proper degree of moisture and flexi- 

 bility. In cases of extensive burns, when a large surface of integument has been 

 destroyed, the loss of the aqueous portion of the blood is remarkable. In those 

 cases which have been fatal, the blood has been found by M. Baraduc dark and 

 inspissated, and the viscera surprisingly dry, with an absence of fluid in all the 

 serous cavities. This inquirer, indeed, considers the gravity of burns in propor- 

 tion to the amount of abstraction of fluid or the drying ; and accordingly in the 

 treatment he holds it to be a principle to counteract this as much as possible by 

 keeping the patients many hours in a bath daily, aided by the use of diluents, and 

 by the dressing of the burnt parts with cerate. 



In the experiments on the limb of the fowl and of the thrush, as well as 

 in all the others, the results show how much the rapid drying of the parts 

 deprived of their integuments checks and prevents putrefaction at a certain tem- 

 perature, and vice versa, how a retardation of drying, from the integuments being 

 left on, favours putrefaction. And this it may be inferred, much in the same 

 manner as an atmosphere loaded with moisture promotes the same change.* 



* A simple experiment illustrates this. Two portions of recently killed lamb were selected. 

 One (No. 1) weighing 168-5 grs. was suspended by a thread, freely exposed to the air of a room 

 varying in temperature from 60° to 65°, i.e., the day and night temperature. The other (No. 2), 

 weighing 1601 grs., was suspended hanging free in a small glass receiver, in which was a little 

 water, and was so covered as to allow ingress of air, and yet almost to prevent any evaporation. The 

 results were strongly marked. No. 1 lost weight rapidly, and soon became hard and dry without 

 acquiring any putrid taint. No. 2, on the contrary, softened and actually liquefied, at the same time 

 becoming extremely putrid. In an experiment similarly conducted over water — but the water 

 exhausted of air and in vacuo — the muscle escaped putridity. This, from the llth July to the 20th 

 August, illustrating in addition, I may remark, the difference as regards tendency to putrefaction 

 between muscle and blood ; the latter, as I have shown elsewhere (p. 25 of this volume), undergoing 

 the putrid decomposition, even in vacuo, being impregnated with oxygen. 



