206 Part III. — Twenty-fifth Annual Report 



(1) Referring, in the first place, to the herrings obtained in August 

 and September, the water percentage is highest in large spent fish, and 

 following closely upon this comes the large full fish. 



Spent " Matties " (Ba.) have a slightly lower water percentage than 

 the large full herrings. The unspent " Matties " (B.) and the " Matt. 

 Fulls " (No. III., August 9th) contain practically the same amounb of 

 water. The lowest percentage of water wa,s present in the " Matties " of 

 August 9th. 



The only point of importance in connection with the water in the muscles 

 of the July herring is that, with the increase in development of the 

 ovaries, there is an increase in the water content of the muscles. 



One may therefore state shortly that the water percentage of the muscles 

 rises as the ovaries become more mature, and the maximum is reached 

 when the fish are spent. 



(2) The Total Proteid Percentage. — There are but sliglt variations in 

 this. It was highest in the " Matt. Fulls " of August 9th and lowest in 

 the " Spents " (C.) of August 9th. As however may be seen from the 

 table, the proteid percentage in spent fish may be very high. 



(3) Goariulahle Proteid. — This is more important as an indication of 

 the nutritive value, as it represents the proteids which are coagulated on 

 boiling the fish. 



Referring to the Lerwick and Kinnaird Head herrings (August 9th), 

 which are more easily compared, the highest percentage is present in the 

 "Matt. Fulls" and "Matties" and the lowest in the "Spents" and 

 " Fulls." The September Lerwick herring—" Fulls " and " Spents "— 

 contained, however, a high percentage of coagulable proteid. 



(4) Fats. — The percentage amount of fat in the fish is probably 

 regarded by most people as the best standard for estimating its nutritive 

 value. It is in many respects the most valuable indication of the value 

 of the herring ; but, as pointed out in my previous paper, it must not be 

 regarded as the sole one. 



There can be no doubt about the results of the analyses. The herrings 

 richest in fat are the " Matties " and " Matt. Fulls," the poorest the 

 " Large Spents " anr* " Large Fulls." The lowest fat percentage was pre- 

 sent in the "Large Spents " obtained from Kinnaird Head on August 9th. 



Taken as a whole, the spent fish have a lower fat percentage than the 

 corresponding full fish, but it is possible that in some cases the fat per- 

 centage of even spent fish may be higher than that of" Fulls." One may 

 easily understand how this may occur, as the fish may have commenced 

 to store fat again. For example, the spent fish obtained from Lerwick on 

 August 9th were evidently, so far as the fat percentage was concerned, in 

 slightly better condition than the Lerwick mature fish and also than the 

 Kinnaird Head spent fish. 



In conclusion, on comparing these East Coast herrings with the West 

 Coast fish (see previous paper), one is mainly struck by the lower water 

 and higher proteid and fat percentages in the former than the latter. 



I never obtained such low fat percentages in the East Coast fish as were 

 obtained in some of the winter West Coast herrings. There are many 

 other points of interest in the tables, but these can be readily appreciated 

 by a study of the various analyses, I have not grouped together the 

 results of the analyses of the male fish, as this was scarcely necessary. 



From a study of the tables given in this paper, and the preceding series 

 of analyses (West Coast herrings), one is struck by the fact that the fish 

 which possess, as a rule, the highest percentage of fat in their muscles are 

 those whose ovaries are still some time short of full maturity. Usually 

 fish with ovaries of 15-20 grammes weight (weight at full maturity about 



