174 
W. D. HALLIBURTON. 
A. — Composition of the Head Cartilage of Sepia. 
The specimens from which the cartilage was taken had been 
preserved for some time in spirit. After having been soaked 
in water for twenty-four hours to remove the spirit, it was 
divided into small pieces, and various portions were treated in 
the following ways : 
1. — Some was boiled with distilled water in a sealed tube for many hours. 
Apparently no change took place in the cartilage. After this time the 
water was poured off, and tested as follows : 
a. It did not gelatinise on cooling. 
b. It contained no evidence of proteids. 
c. Acetic acid gave no precipitate. This showed that no mucin had dissolved 
in the water. 
d. Solution of tannin, acetic acid, and ferrocyanide of potassium, lead ace- 
tate, and mercuric chloride, all gave small amounts of precipitate. 
2. — Hydrochloric acid was added to another portion. In a few hours in the 
cold, the cartilage was completely dissolved ; on adding water to this 
solution, a small amount was reprecipitated. 
3. — Acetic acid was added to a third portion. The cartilage swelled up some- 
what, but underwent no further change. 
4. — To a fourth portion Baryta water was added. The cartilage became dis- 
solved to some extent ; and on adding acetic acid to the solution, a 
precipitate was obtained. 
5. — Sulphuric acid was added to another portion. The cartilage turned of a 
brownish hue, but did not dissolve until the application of a small 
amount of heat, when a dark brown solution was formed. On dilut- 
ing this, and heating it for half an hour in boiling water, it was found 
to possess the property of reducing copper salts. 
6. — To a sixth and last portion, strong solution of caustic potash was added. 
The cartilage became in the course of a few hours disintegrated, and 
to some extent dissolved ; but there was a considerable amount of 
residue which was not lessened by boiling. The solution was found to 
contain no sulphur. 
The conclusions to be drawn from these reactions are as 
follows : 
1. Elastinis absent, because the cartilage is wholly soluble 
in cold concentrated hydrochloric acid. 
2. Keratin is absent, because the part soluble in potash 
contains no sulphur ; and because acetic acid does not dissolve 
anything from the cartilage. 
