156 THE BLOOD. 



identical in properties with what had been called by Halliburton cell 

 globulin-/3 (see p. 82). When cell globnlin-j3 was discovered to be a 

 nucleo-proteid, this also was found to be of the same nature. 1 It can 

 also be prepared from the red corpuscles by Wooldridge's acetic-acid 

 method, or, provided the corpuscles are well caked together by the action 

 of an efficient centrifuge, by the sodium-chloride method of Halliburton. 

 In these experiments the colourless corpuscles may be got rid of by a 

 previous injection of commercial peptone. 



In cats the percentage of phosphorus in the corpuscular nucleo-proteid 

 is 0*68. It produces in tra vascular coagulation when a solution in 1 per 

 cent, sodium carbonate is injected intravenously (Halliburton). 



The lecithin and cholesterin. L^ Hermann 2 and Hoppe-Seyler 3 

 described the phosphorus-containing organic constituent of the cor- 

 puscle as protagon, a substance got in large quantities from medullated 

 nerves, but subsequently it was recognised by Hoppe-Seyler 4 to be in 

 reality lecithin, which is a decomposition product of protagon (see p. 83). 

 Both lecithin and cholesterin are extracted from the corpuscles by ether, 

 and are therefore either free or, at most, in very loose combination 

 with the nucleo-proteid. 



The chemical composition of the white corpuscles has been 

 already dealt with (p. 83). 



The blood platelets. In spite of the large amount of research from 

 the histological standpoint which has been carried out in relation to the 

 blood platelets (Blutpldttchen of Bizzozero), very little is known about 

 their function or their chemical composition. According to Lowit, 5 

 they consist chiefly of a globulin, and play an important part in 

 fibrin formation. As the result of microchemical work, Lilienfeld 6 

 considers that they consist of nucleo-proteid. 



Lowit states that they are not to be seen in the circulating blood, 7 

 and regards them as being produced partly from the white corpuscles, 

 partly from globulins of the plasma, after withdrawal of the blood. 

 They can, however, be seen within capillary blood vessels which have just 

 been removed from animals, and in which the blood is still fluid. 8 

 Mosen failed to find them in lymph. 9 



Their number in the blood has been variously estimated at from 

 180,000 to over 600,000 per c.mm. 10 



BLOOD PLASMA. 



The methods of obtaining plasma from blood, by preventing coagula- 

 tion and allowing the corpuscles to subside, have already been given. 

 Obtained thus from a suspended vein or from a cooled vessel, plasma 



1 Halliburton, Journ. PhysioL, Cambridge and London, 1895, vol. xviii. p. 306. 



2 Arch.f. Anat. u. PhysioL, Leipzig, 1866, S. 33. 



3 Mcd. Chem. Untcrsuch., Berlin, Heft 1, S. 140. 



4 Jbid., Heft3. 



5 Arch. f. exper. Path. u. PharmakoL, Leipzig, 1888, Bd. xxiv. S. 188. 



6 Arch.f. PhysioL, Leipzig, 1892, S. 115. 



7 Virchow's Archiv, 1889, Bd. cxvii. S. 545 ; and "Studien z. Phys. u. Path. d. Blutes 

 u. d. Lymphe," Jena, 1892. 



8 Osier, Proc. Roy. Soc. London, 1874, No. 183. This observation I can entirely confirm. 

 ^Arch.f. PhysioL, Leipzig, 1893, S. 352. See also Druebin, 1892, ibid., Suppl., S. 



211. 



10 See on this subject, Muir, Journ. Anat. and PhysioL, London, 1891, vol. xxi. ; also 

 Brodie and Russell, Journ. PhysioL, 1897, vol. xxi. p. 390, who give reasons for regarding 

 the higher number as more correct. Probably, however, the number varies greatly. 



