FISH-LIVER OILS 515 



chemists. The laboratories of these estabhshments act as process supervisors and 

 also conduct research into improvement of the methods of extraction and preserva- 

 tion. It is difficult to obtain accurate information as to the exact methods employed 

 by a given processor in handling the livers his buyers have purchased since dealing 

 with the livers of different species as well as those from the same species under 

 different circumstances of freshness, etc. requires different treatments. These varia- 

 tions in the processing methods are learned chiefly by experience, and are not 

 divulged lest they fall into the hands of competitors. 



The success of the entire operation of recovering the greatest possible yield of 

 vitamin A from the raw material at hand is the responsibility of the chemist or 

 chemical engineer in charge of the laboratory. The control laboratory is valuable in 

 the disposal of waste materials which result from the process of oil recovery. 

 They contain liver particles and other protein material which would constitute a 

 health hazard ff discharged into a sewer or open water without pretreatment. 

 This pretreatment of waste material is dependent, to some extent, on the process 

 used in removing oil from the livers. In many localities arrangements have been 

 made to treat the waste material along with the regular sewage disposal, where 

 there are no interfering ingredients in the waste. 



As in many manufacturing processes there are volatile products of disagreeable 

 odor, and it is imperative that these be disposed of so that they do not become 

 a public nuisance. Most of the vitamin A extraction plants handle this problem by 

 means of a washing tower which serves to remove the objectionable odors with 

 a series of cold water sprays as gases rise through the tower. In some installations 

 the volatile matter is recirculated through the furnace, where the odors are burned 

 and eliminated. 



The Capsulating Process 



High potency vitamin A concentrates are more easily handled if they are in 

 capsule form. If these concentrates are sold in liquid form in dark-colored glass 

 bottles for home use, the loss of vitamin potency through oxidation is considerable 

 after the bottle has been opened. The pharmaceutical houses have found that the 

 most satisfactory method of distributing the concentrates is in a single dose in the 

 form of an easily swallowed capsule. With the capsule it is possible to include 

 other vitamins in addition to A, which results in a single capsule containing multiple 

 vitamins and of various predetermined potencies. All vitamin concentrates are care- 

 fully assayed before being capsulated. 



The most common method of capsule manufacture is one devised by R. P. 

 Scherer (1933). In this method gelatin, glycerin, and water, in about equal parts, 

 are thoroughly mixed. The mixture is next heated at 160° F (70.1° C) in a thermo- 

 statically controlled "Monel" metal or stainless steel vessel, where coloring matter 

 may be added. When the cooking process is completed, the gelatin mixture is 

 placed in the reservoir of the capsulating machine. Two ribbons of the mixture are 

 extruded from slits, and pass over two large forming rolls. The ribbons are then 

 passed through a mineral oil bath over a guide roll, and then against one another 

 between a pair of die rolls. A heated injection wedge is fitted between the die 

 rolls and between the ribbons. An accurately measured quantity of vitamin con- 

 centrate is forced between the ribbons from a small opening at the bottom of the 

 wedge. The pressure applied to the concentrate forces the ribbons to conform 



