154 J. 0. WAKELIN BAKRATT AND GEORGE ARNOLD. 



N . 



represented by a ^- solution of liydrocliloric acid. As the 



blood-plasma is alkaline to litmus its basicity cannot be 

 determined by adding potassium hydrate. 



Coagulation. — No spontaneous coagulation of the blood 

 of Dytiscus marginal is occurred on standing. 



Composition. — The blood-plasma was found to contain 

 6*6 per cent, to 10'4 per cent, of solids, dried at 110° C. (1 

 c.c. of blood was taken for estimation of total solids). 



On rendering the blood slightly acid with acetic acid and 

 then heatino- it became solid. When the blood was diluted 

 with three parts of distilled water or "85 per cent, solution of 

 sodium chloride, made slightly acid with a 1 per cent, solution 

 of acetic acid and boiled, a brown precipitate formed. After 

 centrifugalisation the supernatant liquid was found to remain 

 turbid (this being apparently due to the presence of ammonium 

 salt in the plasma), so that complete separation of the proteid 

 from the non-proteid solids of the plasma could not by this 

 means be effected. By weighing the brown precipitate after 

 drying at 110° C. it was found that the former was not less 

 than 1'3 per cent.; this figure has little value, however, since 

 the supernatant liquid contained proteid forming a gelatinous 

 mass as evaporation proceeded. 



On adding blood to a large excess of distilled water turbidity 

 appeared, followed by the formation of a white precipitate, 

 showing the presence of globulin. 



The dried solids of the plasma contained about 9 per cent, 

 of ash, which was of a brownish-white earthy aspect. Owing 

 to the small amount available furthei" analysis ot the ash was 

 not possible. 



Osmotic Pressure. — The freezing-point of the blood- 

 plasma determined by Beckmann's method (T3 c.c. of blood- 

 })lasma were employed) was — "77° C, corresponding to an 



• -, M ," . 

 undissociated ^ solution. 



Granular Material. — This consisted of granules 1 ju to 

 •2 ;u in diameter, exhibiting Browuian movement and in part 



