B1 I 



clol or collect betv een it ami | 

 Bome t ime t he » - 1 « * t breaks aw aj 

 in the serum. The latter may l"- p 



opalescent, partly because of the p 

 cause of leucocytes which have m i oul i 



their pov< er of diapedesi 



1 1' a drop of freshly --h ■< 1 blood lined 



will be observed thai the firsl Btep in clottii 

 of fine threads radiating from t"<-i. which 

 platelets. The fine threads are called fibr I 



as to form ;ni interlacing meshwork which 

 corpuscles and leucocytes. B3 the the ultrami< 



Howell 1 and others have observed thai the fibrin 

 thrombin to oxalated plasma is really deposited in t ; 



stalline needles "fibrin needles" which 1 >•*<•< *iii • 

 as they increase rapidly in numbers Although the 

 consists therefore in the conversion of a hydr< - 

 page t- 11 . it is a unique process solution of the \>\ 



esponsible for the formation of the fibrin (fibril 

 colloidal solutions, be precipitated in a variety of ways, bul »nly 



when the conditions are favorable for M 1 clotting thai fibrin 1 



and therefore fibrin threads, are formed. The blood • 

 forms a structureless gel when it clots Howell). 



Methods of Retarding Clotting of Drawn Blood 



To understand the nature of the clotting p 



are res] sible for its occurrence, it is advantaf 



conditions Bomewhal by getting rid of I i corp 



the other formed elements of the M I and tl 



which tip suspended in living blood nam< 1 



separation of blood into corpuscles and plasma is rendi 



by sedimentation or l>\ centrifu 



inhibil or greatly delay the clotting p 1 



purpose are numerous \ of tl 1 



I 1 Keeping tin- blood at a temperatui 



point. This method is. however, 



immediately receh ''-I into narrow 



t ii it- kepi most Btrictly at the low level. I 



other slowly clotting bloods, the n 



tions. 2 I.' ceivii bl i thi 



inila. coated w ith a 1. 



'••<! This method il imp< 



