SUB-DERMAL CONNECTIVE TISSUE OF OCEAN SUN-FISH. 
323 
solution; for proteicl substances, including gelatin and cliondrin and excepting 
peptones, give precipitates insoluble on beating. In testing the boiling-water solu- 
tion of the tissue as given before, the phosplio tungstic acid precipitate was found to 
be insoluble on heating. 
The behavior of the substance with digestive fluids was as follows: (A) Frag- 
ments of the tissue were rapidly digested at 40° 0., when treated with a pepsin 
hydrochloric acid solution. (B) When treated with an alkaline trypsin solution, the 
fragments were attacked with extreme slowness. For this experiment about 40 
grams of the alcoholic tissue were cut up line, well washed to remove excess of 
alcohol, and then treated with a 0.5 per cent sodium carbonate solution of pancreatin, 
to which a few fragments of thymol were added. The temperature was kept at or 
near 40° (J. After four days the tissue had been only slightly attacked, but at the 
end of eight days it was almost completely dissolved. When boiled in water (for 10 
minutes) and then subjected to the action of the trypsin solution, the fragments were 
dissolved almost completely in 24 hours. The same result was obtained by tirst swell- 
ing the washed tissue fragments in dilute acetic acid and then submitting them to 
digestion. The behavior of the subdermal connective tissue toward digestive fluids 
seems to identify it with collogen, the basis of bone, cartilage, and other gelatine- 
yielding substances of the body. True collogens are wholly unaffected by tryptic 
digestion, unless they have been heated previously with water or swelled with acids. 1 
QUANTITATIVE ANALYSIS. 
A preliminary analysis was made to determine the percentage of nitrogen, sul- 
phur, and ash in the dried alcoholic tissue. FTo attempt was made to estimate the 
amount of phosphorus, since the qualitative examination showed only mere traces of 
this element. In this, as iu the following analysis, the nitrogen was determined by 
the Gunning modification of the Kjeldahl method, using mercuric oxide as an oxidiz- 
iug agent, and cochineal as an indicator in the back-titration. Sulphur was estimated 
as barium sulphate in the usual way, after fusion of the tissue with sodium carbonate 
and potassium nitrate. Carbon and hydrogen were determined as usual by combus- 
tion with cupric oxide, a zone of lead chromate being placed after the oxide to arrest 
any sulphur dioxide present. 
About 50 grams of the alcoholic tissue were cut up, dried for several days at 
90° C., pulverized and redried at 110° C., to constant weight. Analysis of this dry 
substance gave the following results: 
Quantity of 
substance 
(grams). 
Constituents. 
Ash. 
Nitrogen. 
Sulphate of barium. 
Grams. 
Percent. 
Grams. 
Per cent. 
Grams. 
Per rent 
of 
sulphur. 
1.5040 
.8162 
. 2829 
.2414 
. 2065 
.6498 
.6836 
.0221 
1.47 
.1337 
. 04746 
. 04032 
. 03458 
16. 37 
16. 77 
16. 70 
16. 71 
.0245 
.0206 
.53 
.42 
Mean . 
1. 47 
16. 64 
.47 
1 Hoppe-Seyler. — Haudbuch d. Phys. u. Path. Chem. Analyse, 6 Auf., s. 270. 
