224 EEPOilT OF COMMISSIONER OF FISH AND FISHERIES. 



specified per cent, 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 off 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 fjuauos from which the most of the fat has 

 been extracted by special processes (Class i^o. 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, chiefly from the skins and bones. These render the process of dry- 

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

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

 recent discover^' of an easy and simple process for removing the larger 

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

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

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

 centrated food, beibre 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 libenited 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 scrap not many days after 

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

 being more readily putrescible than other animal substances, quickly 

 decomposes, and changes 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. Ke-pressing had been tried, using extra strong curbs, with 

 very poweiful pressure, but it failed to give satisfactory results. Ke- 

 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. 



