RESPIRATION IN SOUTHERN WHALES 375 



must be clearly realized that this kind of work has limitations and that post-mortem 

 gas analyses may give misleading results. Every precaution was taken to ensure that 

 the specimens used in analysis were as nearly as possible in the condition which 

 prevailed at the moment of the whale's decease. For instance, a sample of blood was 

 never taken from an abdominal blood vessel, where the fermentation of stomach and 

 intestinal contents might have a local effect on the blood gases. Freshness was of 

 course essential ; though some specimens were from whales which had been dead 24 

 hours or more in order to see the effect of staleness and general decomposition on gas 

 values. 



Technique. A few words should be said about the technique employed. The method 

 of collecting the samples will be described under the appropriate headings. The samples 

 were taken with as little delay as possible from the deck down to the laboratory in the 

 'tweendecks. Here was installed a gas burette similar to the Van Slyke constant-pressure 

 type (Van Slyke, 1917). This burette was specially constructed by Messrs W. G. Flaig 

 and Sons for use on board ship where the accommodation is limited. In addition to the 

 usual features of a gas burette, there was an extra branch tube at the top for the ad- 

 mission of gases, while below the main tap there were three limbs of large capacity 

 instead of the two tubes in the ordinary model. There was a hole near the top of one of 

 the limbs, which was covered by a strong rubber band. The purpose of this hole was to 

 permit the withdrawal of samples of evacuated fluids from a lower limb through a 

 hypodermic syringe and the injection of small quantities of reagents into the lower half 

 of the burette. Strong spiral springs were fitted to the stopcocks so that the burette 

 could be used for mixing gases with fluids under pressure, and the whole apparatus was 

 constructed of specially hard glass and on generous Hues. These modifications were 

 introduced so that the burette might be used as a tonometer and as a Haldane gas 

 analyser as well as in its normal capacity. 



The technique of gas analysis of fresh samples was exactly the normal one. Samples 

 were introduced into the burette, which had previously been evacuated and tested, 

 without exposure to air and were evacuated with vigorous shaking. After allowing 

 10 min. for evacuation, the sample was isolated below the main stopcock while the gases 

 were measured. Carbon dioxide was absorbed by addition of semi-normal caustic soda 

 and oxygen by anthraquinone-beta-sulphonate with sodium hydrosulphite in semi- 

 normal caustic soda. The residual gas in the burette was taken to be nitrogen and inert 

 gases. Some difficulty was at first experienced in bad weather in reading the gas volumes, 

 since the roUing of the ship caused a pulsation of the mercury column. This was over- 

 come by keeping the burette with its rubber tube and levelling bulb all in a fore-and-aft 

 plane and by restricting the surge of the mercury in the tube by a screw clip. Tempera- 

 tures were taken from a thermometer suspended beside the graduated part of the burette ; 

 barometric readings from the ship's barometer. All gas volumes mentioned are corrected 

 to normal temperature and pressure unless otherwise stated. Tests were mads to ensure 

 that gases were being fully extracted from liquids by evacuating water which had been 

 allowed to stand in contact with air at various temperatures. The results given by the 



