260 



Dr. W. D. Halliburton. 



which has tlie properties of fibrin ferment. It might be urged that 

 the ferment is not identical with the globulin, but is only closely 

 associated with it . Such an objection seems to me to be a mere splitting 

 of hairs. If the ferment is so closely associated with the globulin 

 that none of the methods nsed of preparing the globulin pure are 

 capable of separating it from the ferment, and if, moreover, the 

 activity of the ferment is destroyed when the distinctive characters 

 of the globulin are destroyed, as by heating to 75° C, then we are not 

 justified in saying that the globulin is different from the ferment, 

 until some method is shown by which they may be separated. 



After I had performed the experiments just related, the question 

 naturally arose, is this cell globulin the same thing as what has been 

 termed fibrin ferment when prepared from serum ? The experiments 

 that I performed in attempting to find an answer to this question 

 were as follows : — 



A large quantity of cat's serum was taken, and to it was added 

 10 to 15 times its volume of absolute alcohol. The resulting precipi- 

 tate was allowed to stand under the alcohol for about three months ; 

 the alcohol was then filtered off, and the precipitate dried over sul- 

 phuric acid and powdered. On extracting this powder with water, 

 especially with warm water, a very active preparation of fibrin ferment 

 was obtained. Like all preparations of the fibrin ferment, it gave the 

 xanthoproteic reaction, but sufficient proteid was not present to enable 

 one to identify it. The extract was therefore concentrated at 40° C. ; it 

 was then found to contain a proteid which was coagulated by heat at 

 75° C. It was precipitated by dialysing out the salts from its solutions, 

 and it was also precipitated by saturation with magnesium sulphate ;* 

 the precipitate produced by magnesium sulphate was collected, washed 

 with a saturated solution of magnesium sulphate, and redissolved by 

 the addition of water, the adherent salt rendering it soluble. This 

 solution has very marked ferment properties ; it hastened the coagu- 

 lation of salted plasma ; it caused pericardial fluid to clot rapidly ; and 

 it also hastened the coagulation of pure plasma obtained from the 

 jugular vein of the horse. This last-mentioned experiment is of 

 especial importance, as here the plasma was unmixed with any foreign 

 substance. The jugular vein of a horse was removed after being 

 ligatured in two places to prevent the blood escaping ; the " living 

 test-tube " was suspended in a cold place over night, and in the 

 morning the corpuscles had subsided ; the plasma above these was 

 almost free from corpuscles ; and when removed from top of the vein 

 by a pipette did not clot for about half an hour at the temperature of 

 the air (11° C.) ; but a similar portion to which a few drops of 



■ * After filtering off the precipitate produced by magnesium sidphate, the filtrate 

 contained the merest trace of proteid, and on dialysing away the excess of salt, it 

 was found to hare lost all the properties of fibrin ferment. 



