40 



SCIENCE 



[N. S. Vol. LII. No. 1332 



vial served to hold a gross specimen of eoagn- 

 lating plasma in whicli tlie time of appearance 

 of the transparent and opaque stages could be 

 compared with that of the appearance of fibrin 

 needles in the ultramicroscope cell. However, 

 as it was found difficult to determine the 

 earliest moment at which the viscous plasma 

 could be considered to have entered the gel- 

 stage, a more delicate criterion of the onset of 

 this transparent stage was devised by using 

 (3) the control cell. This cell, being of the 

 same size and shape as the ultramicroscope 

 cell and being filled at the same time, could be 

 assumed to favor a progress of coagulation 

 synchronous with that occurring within the 

 cell of the ultramicroscope. The tubal pro- 

 longation of the control cell was immersed at 

 frequent intervals beneath the surface of a 

 normal saline solution, and a very small 

 amount of plasma allowed to escape into this 

 fluid. If the plasma at once diffused through 

 the salt solution it is clear that it was still in 

 a state loi fluidity; if, however, it emerged 

 from the tube in the form of a delicate, trans- 

 parent " worm " which floated in the solution, 

 preserving the contour of the tube, the plasma 

 was considered to have entered the transparent 

 gel-stage. This proved to be a very delicate 

 test ; transparent " worms " could be obtained 

 at such an early stage that agitatixDn of the 

 liquid in which they were suspended would 

 cause them to vanish into the solution — a de- 

 gree of gel-formation too slight to be discerned 

 by the observation of plasma contained within 

 the homeopathic vial. 



In each experiment, the time at which the 

 containers were filled was recorded; likewise a 

 note was made of the time at which fibrin- 

 needles were first to be seen with the ultra- 

 microscope, at which a transparent worm-like 

 gel could first be obtained from the control 

 cell, and at which an opaque clot appeared in 

 the homeopathic vial. The point of interest 

 lies, of course, in the time relation between 

 the occurrence of the transparent gel-stage 

 (as evidenced by the control tube) and the first 

 appearance of fibrin needles under the ultra- 

 microscope. A typical experiment will serve to 

 exhibit this relation : 



BLOOD OBTAINED FROM VEIN ( HORSE) AT 2:25 P.M.; 

 FILTERED AT 3:30 P.M. 



Such experiments demonstrate clearly that 

 all of the reactions leading to the formation 

 of fibrin have occurred before the transparent 

 gel-stage appears ; for fibrin needles are demon- 

 strable in the coagulating plasma in the earliest 

 stages of gel-formation. Indeed, in a number 

 of experiments, a few scattered needles of 

 fibrin were seen with the ultramicroscope be- 

 fore any gel-formation could be demonstrated 

 in the plasma. Microscopically then, the only 

 difference between the so-called transparent- 

 stage and opaque stage of coagulation lies in 

 the greater number of fibrin needles present in 

 the latter. Their gradual development can be 

 watched with the ultramicroscope, and many 

 such experiments (in which the oxalated and 

 Tuioxalated plasms of man, horse, cat and dog, 

 were tested) prove clearly that the macrosooj)- 

 ically observed transition of a liquid plasma 

 through a transparent gel-stage into an opaque 

 fibrin clot, represents merely a continuous pro- 

 gression of fibrin-formation. 



SUMMARY 



There is no reaction-basis for the division 

 of the process of blood-coagulation into the 



