224 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



specified per ceut. of oil is lost, and a portion of nitrogen is also lost, re- 

 sulting from the partial decomposition of the mass, the formation and 

 escape of ammonia. It were better, if practicable, to drive oli' the water 

 at once upon withdrawal from the press, so as to prevent the loss in 

 question." 



Goodale's new process. 



293. I have spoken of fish ijuanos from which the most of the fat has 

 been extracted by special processes (Class No. 5, of page 000). One of 

 these is Mr. Goodale's, of which Mr. Maddocks speaks as follows: 



"What has hitherto prevented the driving off of the water imme- 

 diately by artificial heat has been the presence of so much oil, together 

 with the gelatinous or gluey matter which is developed during the cook- 

 ing, chiefiy from the skins and bones. These render the process of dry- 

 ing the scrap a very difficult and tedious one, so much so that compara- 

 tively little has been put into the market in that desirable form. The 

 recent discovery of an easy and simple process for removing the larger 

 part of the oil, and also at the same time the gelatinous hinderance to 

 drying, gives promise of a speedy change in this respect. While pursu- 

 ing investigations relative to utilizing the menhaden as a source ot con- 

 centrated food, before referred to, Mr. S. L. Goodale, formerly secretary 

 of the board of agriculture, discovered that it was chiefly by the agency 

 of the gelatine that the remaining oil was held in the scrap. He found 

 by thoroughly washing new scrap with sufficient hot water, and agita- 

 tion, that it lost its jellyish consistence and slimy feel, and that the oil 

 globules were liberated from their lock-up in the tissues, so that the 

 greater part could be easily recovered by draining and repressing, and 

 also that after such washing it could be pressed much drier than before. 



" We can now readily understand why it is that oil, together with 

 a putrid, watery liquid, leaks away from new scraj) not many days after 

 it is removed from the press. It is simply because dissolved gelatine, 

 being more readily putresciblo than other animal substances, quickly 

 decomposes, and chauges to a thin, offensive liquid, which partly drains 

 off. This decomposition, or the change of consistence attending it, so ' lets 

 the bars down,' that more or less oil escapes, while subjected to no press- 

 ure whatever, except its own weight. 



" Thus by a very easy process, the oil product may be largely increased, 

 the scrap left free from the gluey hinderance to drying, and with less 

 water to be dried out. 



" It may appear strange that so simple a method should not have been 

 discovered sooner, but such is the fact. Work had been done on both 

 sides of it. Ee-pressiug had been tried, using extra strong curbs, with 

 very powerful pressure, but it failed to give satisfactory results. Ee- 

 cooking had been resorted to, which resulted in injury to the oil and in 

 the development of an additional amount of the gelatinous matter. It 

 is now seen that a simple thorough washing in hot water accomplishes 

 the desired end, with neither of these objectionable results. 



