CHKMICM. I'.ASIS OF THK ANIMAL U.MV. 



Fibrin-ferment. 



I'.uchanan'- wi.rk (1831) on tin- dotting of blood, more par- 

 ticularly his exj.,-riments with 'washed rl..t.' when examined ii: 

 the ; 'tir present knowledge, -li..u< dearly that i 



din;,' with that fa. tor in tin- whole process which 



independently red l.\ Alexander s. hmidt and more spe- 



.iK-d l>y him in 1*7'J under the name of ' til>ri: 

 nient.' ' It- !iad Keen ton-shadowed in some experiments 



mad-- ke. in which he showed that the Hliriintplastic aetion 



of precipitated paraglobulin was parti] dejM-ndent upon 



the admixture of some other >ul. stance, which he regarded as the 

 truly tilirinoplastic fat-tor. Thus, he showed among other things 

 nore a serum is diluted before the paraglohulin is precipi- 



from it liv means of CO,., the less marked are its tiluino- 



-. 2 Further. Mantegazza had in 1871 put forward 



the view, also held }.y Uuchaiian, that the white coi),u>cles play 



imjx>rtant part in the formation i.f tilirin, without in any 

 :isin^' the substance which he suggested was prob- 

 ably dis' I Mum them as the determinant of the whole 

 process. 8 The time was thus rijN- for Schmidt's discovery. 4 He 

 prepared the ferment l>y juvcipitatint: serum with !." ijO vol- 



iu r alcohol ; the precipitate was treated for /// 

 14 da\> with the alcohol to insure complete (?) coagulation and 

 insolubility of the proteids; after which time it was removed W 



ion. dried in vacuo over sulphuric acid, pulverised, and 



with distilled water in volume equal to twice that of 



the xeiuin originally employed. The ferment solution thus ob- 



i i- by no means pure, and n< 'ti\e. M : ntly 



aarsten has obtained the ferment in solution free from pnra- 

 glol.uliu. 5 11^- saturates serum with magnesium Milphate at 30, 

 and "'Iters otl the precipitated para^Iobu^iu at the same temj_M-ra- 

 t_ure. Th>' filtrate he dilutes with nine volumes ot water, and t 

 tln^ adds gradually, and with continuous stirring, dilute caustic 

 so<la until a IM-I inaiient. llocculent. ami fairly c<pious i>re<-ipitat<' 

 j fanned. Tliis precipitate carries the ferment down mechani- 

 cally, and i- finally washed, pressed. -u-|-ndcd in water, dissolved 

 by a< i to a neutral -olutiou.and dialysed till free from 



ordinary puriMtses an extremely active ferment solution 



le must readily ofiuined by Hamgee's method f extra* tii i ;_' 



< >-called ' wasjied IdcxKl dot ' with 8 p.c. solution of sodium 



chloride.* The solution in this case contains ti large amount of 



1 An account of Buchanan ' experimeot* ha* beea jfvM br Gamgee. Pkytiol. 

 Ckm,< . i 8e abo Jl. of l^ vo/. Vol. n. (1879). p 145. 



Al.th.), 1867, 8. 891. 



\ !t. in Ma 



rrt.n:..r' .)-.', I! 



Ibid. R! KTl x \ x I - 



QHBgM 



