SEELYE: CIRCULATORY SYSTEM OF DESMOGNATHUS. 341 
urodele integuments. It also seems to show that the skins of lunged 
forms, e. g., Diemyctylus, are more quickly and easily permeated by a 
gas than are those of the lungless animals. The skin of Amblystoma 
opacum, the intermediate form with rudimentary lungs, was slowest 
in first allowing the gas to pass through, but the excess of co 2 showed 
more quickly here than in the case of the lungless forms. Of course it 
must be remembered that, as we saw in our anatomical study of the 
integument, the majority of the blood vessels are intra- and not sub- 
integumental, so that normally a gas would not have to pass through 
the basement layer of the cutis as it did in the experiment. 
Time 
D. fusca 
S. bilineatus 
A. opacum 
I), viridescens 
2 P. M. 
clear 
clear 
clear 
clear 
2.40 p. m. 
milky streaks 
milky streaks 
2.55 p. m. 
milky streaks 
3.45 p. m. 
more milky 
milky streaks 
more milky 
5 P. M. 
evenly milky 
evenly milky 
evenly milky 
evenly milky 
10 P. M. 
very milky 
very milky 
clear 
clear 
6 A. M. 
clear 
clear 
clear 
clear 
The second group of experiments dealt with the living animals, and 
included a series of tests of the effect of chloroform taken into the 
mouth, pharynx, and esophagus, as compared with its effect on the 
skin. Here again lungless and lunged forms were used. Desmog- 
nathus fusca was the animal experimented upon, and Diemyctylus 
viridescens the control animal. 
The first of these tests, for the effect of chloroform taken in at the 
mouth, was set up as shown in fig. C. 
A glass tube (g. /.), open at both ends and large enough to receive 
the head of a salamander, was employed as a chloroform chamber. 
Strong pieces of thread were tied around the fore legs of the animal, 
and these were fastened to the end of the glass tube through small holes 
(h.), previously burned in the glass, so that the animal’s head was 
firmly held inside the tube. A strip of absorbent cotton soaked in 
water (c'.) was then placed at the joint to make it as nearly tight as 
possible. Chloroform on an absorbent cotton wad (c.) was then intro¬ 
duced into the tube and the end opposite the animal’s head closed with 
a rubber stopper ( 5 .). I 11 order to maintain as normal a condition as 
possible for the parts exposed to the air, a damp towel was placed 
under the animal’s body, and the skin kept moist and cool during the 
