Gelatin The fillings of both are made by combining ground pork with gelatin cubes, and in the process of cooking, the gelatin melts, creating a soupy interior with a characteristic gelatinous stickiness. Gelatin is used for the clarification of juices, such as apple juice, and of vinegar. Isinglass is obtained from the swim bladders of fish. It is used as a fining agent for wine and beer. Besides hartshorn jelly, from deer antlers (hence the name "hartshorn"), isinglass was one of the oldest sources of gelatin. The consumption of gelatin from particular animals may be forbidden by religious rules or cultural
Elasmobranchii grooved to constitute a clasper for the transmission of sperm. These fish are widely distributed in tropical and temperate waters. Many fish maintain buoyancy with swim bladders. However elasmobranchs lack swim bladders, and maintain buoyancy instead with large livers that are full of oil. This stored oil may also function as a nutrient when food is scarce. Deep sea sharks are usually targeted for their oil, because the livers of these species can weigh up to 20% of their total weight. Fossilised shark teeth are known from the early Devonian, around 400 million years ago. During the following Carboniferous period,