SEA-FISHERIES LABORATORY. 395 



of the animal as an individual. Under normal conditions 

 of freedom of the animal, these would probably be con- 

 siderably higher, but even if they be placed at double the 

 quantity, they scarcely account for the food a free lobster 

 would use, and this indicates, as has been previously 

 observed in Echinus esculentus (3) that a great portion of 

 the daily consumption of food is probably, at this grade 

 of animal life, used for purposes of sexual metabolism. 



Thus if the daily consumption of oxygen and 

 output of combined oxygen as carbon-dioxide be 

 totalled up for the entire period, the result appears 

 that the oxygen consumed amounted to 4*760 grams 

 of oxygen, and the oxygen appearing in carbon- 

 dioxide to 4783. This yields a respiratory quotient 

 of approximately unity, indicating that carbohydrate or 

 protein chiefly have been oxidised. The weight of carbo- 

 hydrate in a combustion is slightly less than that of the 

 oxygen required for its combustion, and a calculation on 

 the assumption that all the material utilised was sugar 

 gives 4'4 grams of sugar. The result would not much 

 vary from this, if protein were being oxidised. If allow- 

 ance be made for the periods of interruption, and exposure 

 to light, and for changing the sea-water, the interval may 

 be taken very closely as one of 27 days, and on this basis 

 the daily consumption of organic matter reckoned as carbo- 

 hydrate amounts to only 016 gram. It is usual in stating 

 such results to quote the result at so much per kilogram of 

 animal weight. This is a most pernicious custom since 

 the metabolic oxidation is not at all proportional to body- 

 weight, but much more nearly to animal surface, a I any 

 rate in warm-blooded animals. If this incorrect method 

 of statement be adopted, the consumption stands al 0'8 

 gram of carbohydrate per kilogram of body-weighi of 

 lobster per diem. This result is confirmed by the next 

 experiment. 

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