1893.] and other Varieties of Liquid Extravascidar Blood. 567 



The figures in column 2 have not been corrected for the dilution effected by the 

 injection of the peptone solution. Taking the blood as 1/13 of the body weight 

 the amount of peptone solution introduced would effect a dilution of from 3'9 to 

 6'5 per cent. The figures in column 2 ought therefore to be increased by this 

 fraction in order to be strictly comparable with the figures in column 1. 



The above tables show that Dog's peptone blood differs from oxa- 

 lated, leech- extract, and 8 per cent. MgS0 4 blood (this last blood was 

 employed throughout as the standard of comparison) in containing a 

 mere tithe of the normal number of leucocytes. These missing 

 leucocytes have either remained behind in the tissues or in the 

 internal vessels, or they have disintegrated and have passed into 

 solution in the plasma. I have endeavoured to decide between 

 these alternatives by making comparative estimations of the 

 leucocytes in the mesenteric veins, and in the carotid blood, and 

 fuither by making a series of careful histological examinations of 

 the various organs which might be expected to harbour the leuco- 

 cytes (I selected the liver, the kidney, and the heart muscle for this 

 purpose). In no case was I able to find any trace of stasis or of 

 emigration of leucocytes either in the Dog or in the Rabbit after 

 peptone injections. I, therefore, feel justified in concluding that in 

 all probability the leucocytes have dissolved in the plasma. I 

 believe that this view is borne oat also by a consideration of the 

 chemical properties of peptone plasma, notably by the fact that it 

 deposits on cooling a heavy precipitate of a nucleo-albumen, which is 

 probably identical* with Wooldridge's tissue or cell-fibrinogen, in 

 other words, identical with the characteristic albuminous constituent 

 of the white blood corpuscle. 



This " cold precipitate " is not obtained from any other plasma 

 except from oxalate plasma, where I have obtained it, after allowing 

 it to stand for 24 hours before separating it from the white blood 

 corpuscles. Under these circumstances a certain disintegration of 

 white blood corpuscles takes place in this plasma. The non-occur- 

 rencef of a " cold precipitate " in leech-extract plasma is in accordance 

 with the fact that this plasma contains no disintegrated leucocytes. 

 The non- occurrence of the precipitate in salted plasmas (Halliburton) 

 probably similarly depends on the fact that the white blood corpuscles 

 do not disintegrate readily in these plasmas, but it may be noted that 

 Wooldridge showed that the addition of neutral salts prevented the 

 precipitation of his " cold precipitate." 



We have thus reason to believe that the occurrence of a precipitate 

 on cooling peptone plasma is due to the fact that the plasma contains 



* Vide Pekelharing's identification of Wooldridge's " cold precipitate," or 

 " A-fibrinogen," with the nucleo-albumen of the cell (' Verhandl. d. Konink. Akad. 

 v. Wetenschappen, Amsterdam,' 2nd Sect., Deel 1, No. 3). 



t See Dickinson, ' Journ. of Physiol..' vol. 11. 



2 p 2 



