NOTE 0>f THE FORMATION OF FIBRINB. 25/ 



preparations. Having made a selection I deposited a drop of 

 the concentrated solution of nitrate of rosanilin on to glass 

 and allowed it to remain for a few moments, then washed it off 

 with a fine jet of distilled water. The red, pale and colourless 

 corpuscles, with their ramifications and the most delicate fibrils 

 of fibrine, then become visible under a high power. These pre- 

 parations may be mounted dry and will keep for a great length 

 of time. If the process be performed as rapidly as the dexterity 

 gained by an oft repeated experiment will ullow, the appearances 

 presented in fig. 1 will be seen. In this it will be observed that 

 the circular appearance of the corpuscles is perfectly preserved, and 

 that every shade of colour may be found, from the normal red 

 corpuscles down to the colourless N orris corpuscle, which only 

 takes the faintest tint of pink. If, however, the glass surfaces 

 be allowed to remain in contact for a moment, the colourless 

 corpuscles are found to have lost their globular form and to 

 have become pyriform or elongated, as shown in fig. 2. On 

 leaving the glass surfaces still longer in contact, these pale cor- 

 puscles are observed to undergo a remarkable change, they 

 send out long processes or tails, which bifurcate and divaricate 

 in every direction. Kg. 3 gives some specimens of these 

 branching cells carefully drawn with the camera lucida ; they 

 were, it is true, not all obtained from the same plate, but have 

 been grouped together for convenience. Pig. 4 gives perhaps 

 a more remarkable specimen of these branching corpuscles. 

 All the former specimens are from human blood, but figs. 4* 

 and 5 are from rabbit^ s blood. On allowing a still longer 

 interval to elapse, so that it is more than probable that 

 coagulation would occur in a film of blood lying between two 

 glass surfaces, and on separating these surfaces, perfect speci- 

 mens of fibrine may be obtained after staining. These are 

 represented in figs. 6 and 7. On now searching the field the 

 pale corpuscles, which could formerly almost always be dis- 

 covered, are nowhere to be found, and the conclusion is forced 

 upon one that the branching corpuscles have developed or 

 broken down into fibrinous threads. Small granules (d., fig. 6) 

 are, however, found from which threads of fibrine appear to 

 spring. These granules are described in j\I. Ranvier^s " Traite 

 Technique d'Histologie/' as the centres of fibrine formation. 

 They appear to me to be all that is left of the pale corpuscles, 

 whose intermediate transformations have not before been recog- 

 nised, but may, I believe, perhaps be identified with the appear- 

 ances and changes which T have described and figured. I 

 repeated these experiments a great number of times, with the 

 object of arriving at the exact moment when I should be able to 

 verify this hypothesis, and trace the fibres of fibrine into one or 



