Contributions from the Biological Laboratory of the U. S. Fish Commission, 
Woods Hole, Massachusetts. 
THE CHEMICAL COMPOSITION OF THE SUB-DERMAL CONNECTIVE TISSUE 
OF THE OCEAN SUN-FISH. 
By ERIK H. GREEN, A. M. 
The tissue under examination was obtained from a sun-fislx* taken near the labora- 
tory of the United States Fish Commission at Woods Hole, and at the time the study 
was undertaken had been preserved in alcohol for nearly a year. The preserved 
fragments were of a creamy white color, homogeneous, very tough and inelastic, and 
under the microscope were found to consist almost entirely of elastic-like fibers. As 
no reference to the chemical composition of this substance could be found, the following 
analyses were undertaken to determine (1) whether the tissue was composed wholly 
of elast.iu, and (2) what was the essential constituent if the tissue was found not to 
be composed of elastin. 
The analyses were conducted as follows: A few grams of the alcoholic tissue were 
cut into small fragments, rinsed in water, and dried at 110° C. When dry the frag- 
ments were of yellow color, semitransparent, hard, and brittle. They were insoluble 
in hot or cold 10 per cent sodium carbonate, but cold 50 per cent acetic acid caused 
them to swell enormously, although they did not dissolve. The dry fragments were 
soluble in strong potassic hydrate, in hot 1 per cent potassic hydrate after one hour, 
in cold 7 per cent potassic hydrate after two hours, and in the hot 7 per cent potassic 
hydrate were dissolved in a few minutes. Deflagrated with soda and niter they showed 
the presence of sulphur and of a trace of phosphorus. 
The alcoholic tissue was insoluble in ammonia (sp. gr. 0.955), in lime water, in cold 
1 per cent hydrochloric acid, and in hot or cold 10 per cent sodium carbonate. It was 
slowly soluble in boiling water, cold 10 per cent hydrochloric acid, cold 1 per cent 
potassic hydrate, and glacial acetic acid. It was readily soluble in strong hot hydro- 
chloric acid, and nitric acid, in cold potassic hydrate (14 per cent), and in hot 5 per- 
cent potassic hydrate. 
A characteristic of collogen is its property of gelatiuization. To test this property 
in the tissue under examination, the following experiments were made: About 50 
*The sun-fish, Mola viola (Linnaeus), is found on the Atlantic coast, in summer as far north as 
the Newfoundland Banks. It occurs in such numbers that ten or more may be seen in a single day, 
the large black dorsal fins elevated above the surface of the water betraying the presence of tiio 
animals as they drift leisurely along. Their total unfitness for food and their pelagic life have 
rendered them safe from the persecutions of the fishermen, and not only are they abundant, but the 
individuals attain to enormous size. Specimens 7 or 8 feet in length weigh several hundred pounds. 
A very large percentage of the weight of each individual is made up of a firm tissue superficially 
resembling blubber, but not oleaginous. By the following chemical analyses this tissue, heretofore 
considered worthless, is shown to yield collogen, an albuminoid, which is the basis of all glues and 
gelatins. The fish are thus shown to have considerable commercial value. — II. C. Bumpus. 
R. C. B. 1899 21 321 
