SCOTT, STUDY OF CHANGES IN MUSTELVS CANI^ 



45 



semi-permeable structures. From what is known of other animals, it is 

 safe to infer that a reasonable excess of water in the blood would be elimi- 

 nated by the excretory organs. On the other hand, it has already been 

 shown that at the time of death the freezing point of the blood has risen 

 21.9 per cent. If the blood be merely diluted, the decrease in solids, 

 organic and inorganic, should be proportional to the increase in water. 

 None of the previous investigations contain references to the percentage 

 of water in the blood under the experimental conditions here described. 

 I obtained data with regard to this matter as follows : A certain quantity 

 of blood was drawn from the caudal artery of a dog-fish taken from sea- 

 water. After the artery was closed, the specimen was placed in fresh 

 water for about one hour. The fish was then removed and a second sam- 

 ple of blood was obtained. Both samples were weighed, placed in a hot- 

 air bath at a temperature of about 100° C. and dried to constant weight. 

 The percentage of the dried material was then computed and from this 

 value the percentage of water was obtained. The results are shown in 

 Table XVI. 



Table XVI. — Percentage of water and solids of the hlood of Mustelus in sea- 

 water and after immersion in fresh icater 



A — Normal blood 



B— Hypotonic blood 



Water 



Solids 



Water 



Solids 



85.39% 



14.61% 



88.28% 



11.72% 



87.04 



12.96 



89.80 



10.20 



87.06 



12.94 



88.94 



11.06 



86.76 



13.24 



88.81 



11.19 



89.08 



10.92 



89.69 



10.31 



84.38 



15.62 



87.09 



12.91 



82.36 



17.64 



87.23 



12.77 



82.69 



17.31 



85.46 



14.54 



87.60 



12.40 



88.49 



11.51 



86.65 



13.35 



87.86 



12.64 



87.69 



12.31 



88.83 



11.17 



88.18 



11.82 



89.26 



10.74 



89.41 



10.59 



91.01 



8.99 



Average =86. 48% 



13.52% 



88.48% 



11.52% 



The average percentage of water in normal blood is found to be 86.48, 

 while that of the blood of the same specimens after immersion in fresh 

 water is 88.48, a gain of 2.0 per cent. Is this gain in water sufficient to 

 account for a rise in the freezing point of the blood of 0.40° ? I have 

 found it necessary to dilute sea-water which has the same osmotic pres- 

 sure as dog-fish blood, 20 per cent with distilled water in order to get a 



