326 Addis 



Milian's Method. 



Drops of blood are allowed to fall on numbered glass slides. From 

 time to time the slides are tilted and the contour of the drop watched. 

 When the drop remains convex instead of sagging down, coagulation is 

 assumed to have occurred. 



Hinman and Sladen (36) have modified this method by only including 

 drops of uniform size. They recommend it as a " quick, convenient, and 

 practical means of determining the coagulability of the blood," and state 

 that it is thoroughly reliable. They hold, however, that " it is only marked 

 differences in temperature which affect the time, which, as a rule, are not 

 met with in the wards or in the laboratory." As I have already shown^ 

 this is far from being true, and the great variations in the coagulation 

 time as determined by this method are principally due to slight changes in 

 temperature. 



Biffi's Method. 



Five loops such as are used for bacteriological work are made on a 

 platinum wire which is fused into a glass rod. The rod passes through the 

 cork of a jar half full of water. The wire is drawn through a drop of 

 blood so that etich loop takes up a film of blood. At short intervals of 

 time the films are successively pushed down into the water until one is 

 reached which does not diffuse into the water but remains unaffected. This 

 is taken as indicating coagulation. 



I found, in using this apparatus, that whenever the wire touches the 

 water the blood in all the films becomes diluted. I was not able to find a 

 way of obviating this difficulty. I have not seen any reports of work in 

 which this method was used. 



Kingston Fox's Method. 



A series of calibrated capillary tubes are filled at intervals of half a 

 minute with blood from the same wound. After some time a rubber nipple 

 is applied and the blood expressed into water. The end-point is the time 

 when the blood no longer diffuses in the water, but remains as a definite 

 worm-like clot, " or until the contents have become so dense that they are 

 with difficulty expiessod. This occurs, in some cases, apart from the forma- 

 tion of a woiin-like clot, the mass being partially diffusible in the water." 



(Coagulation times taken at five different temperatures are given in order 

 that corrections to the standard temperature of 60° F. may bt- made. No 

 formula is given foi- this reduction, which " must therefore be made from 

 the diagram graphically." 



Vierordt's Metliod. 



This was the first ciinlcal nujthod for determining the coagulation time. 

 A graduated glass tube with a bore of I mm. is filled w^ith blood up to the 



