SEA-FISHERIES LABORATORY. 389 



crustacean can go on for hours living and producing 

 carbon-dioxide in sea-water from which practically all 

 dissolved oxygen has disappeared, and under such condi- 

 tions the respiratory quotient for the entire period may 

 far exceed unity, rising to a value lying between three and 

 four, and pointing to some molecular rearrangement in 

 the metabolism of the animal. After such exposure to low 

 oxygen values, it was found that the animal recovers 

 perfectly and becomes quite normal within a few minutes 

 when placed in normal sea-water. 



But in regard to the normal food requirements and 

 rate of oxidation and output of carbon-dioxide, some more 

 accurate measurements were evidently required, lasting 

 over a much longer period, and with a large volume of 

 sea-water renewed at such intervals that the dissolved 

 oxygen value never fell so low as to embarrass oxidation. 



In August and September, 1912, four prolonged 

 experiments were accordingly instituted at the Port Erin 

 Laboratory, in which animals were kept under daily 

 observation for a continuous period of over thirty days, 

 during which interval practically no food was consumed 

 by the animals. Our object, at the outset, was to deter- 

 mine metabolism over an initial period of a few days, and 

 then commence feeding, but the animals refused food 

 under the conditions of captivity. The remarkable result 

 was obtained that the animals gained weight slightly under 

 such conditions, except in one case, and there the loss 

 in weight was small. The animals were all alive and 

 active at the end of the period. The metabolism showed 

 no groat falling off in activity throughout the experiments 

 except an apparent one, lasting only a lew days in the 

 middle of the interval. This falling off was discovered t<> 

 be entirely fictitious, and due to a growth of vegetable 

 matter in the reservoirs, tor on covering these over fco 



