APPENDIX. 
Analysis of the Oils produced by cp:rtain Indian Rays and other 
Aquatic Vertebrates. 
By D. Hooper, F.C.S., Industrial Section, Indian Museum. 
Among the specimens of fish captured by the ‘ ‘ Golden Crown ’ ’ and handed over 
to the Indian Museum for determination have been several species which yield large 
quantities of oil. The collection and use of marine animal oils in some parts of the 
world constitute important industries, but in India these fats are very rarely utilised, 
and their chemical composition and properties have never been studied. Whale and 
seal oils are occasionally imported for leather dressing and other purposes, and it does 
not appear that any serious attempt has been made to exploit the oils of Indian fish. 
The first oil examined was that of the Gangetic Dolphin {Platanista gangetica). 
This animal is called susu, sehu and sisar , and the oil is locally used as an embrocation 
for rheumatism and as an illuminating agent. The oil is yellowish-brown becoming 
reddish-brown on keeping, has a faint fishy smell, and deposits no solid fats at the 
winter temperature of Calcutta (i8 — 22° C.). 
The following constants were obtained ; — 
Specific gravity at 15° C. . . . . . . -921 
Acid value . . . . . . . . 21 36 
Saponification value . . , . . . 198 ’8 
Iodine value . . . . . . . . 106 9 
Reichert-Meissl value . . . . . . 71 
Fatty acids, per cent. . . . . . , 94-0 
Melting point of . . . . . . 25'5° C. 
Acid value of . . . . . . 205-0 
Iodine value of . . . . . . 116-5 
Although it is allied to the sperm whale, the oil of this animal contained no sperm- 
aceti. There is a fair amount of free fatty acids, but there is only a small proportion 
of the more volatile fatty acids. The solid fatty acid, calculated as palmitic acid, 
amounted to about i6 per cent. Such an oil would be of value for currying purposes, 
for burning and for lubricating fine machiner^L The other oils examined were those 
of the livers of certain large fish brought from the Bay of Bengal, and identified by 
Dr. Annandale. The livers were from the following species : — 
1 . White Sting-Ray ( T rygon microps) . 
2. Common SiOiVj-Fish. {Pristis perottetii) . 
3- Spotted Shark {Stegostoma tigrinum). 
4. Shark Ray {Rhamphobatis ancylostomus). 
