Action of certain Reagents upon Coloured Blood- Corpuscles. 115 



pyrogallic acid — which had become yellow through having been kept 

 a day or two after it was made — the following" appearances weie 

 observed : — The biconvex oval red corpuscles soon became globular, 

 and in a very short time were observed to recoil or give a sudden jerk, 

 a small portion of the contents being at the same time extruded in a 

 direction opposite to that in which the recoil took place. In fact, the 

 recoil seemed to be due to the sudden extrusion of a small portion of 

 the contents of the corpuscle at one place, or in rare cases at two 

 places, at the margin of the corpuscle. These small extrusions resem- 

 ble, but are not identical with the " pullulations " described by Dr. 

 Roberts as the effect of the action of a solution of tannic acid.* 



It is very interesting to watch the sudden effect. The globular 

 corpuscle suddenly jerks in one direction, and simultaneously with 

 this, one observes a small mass of the contents of the corpuscle pouring 

 out of a very fine aperture or crack at one side of the corpuscle. (PI. ] , 

 fig. 1, b, c, d.) The motion or jerk seems to be caused by the sudden 

 ejection of material, and so the corpuscle moves in an opposite direction. 

 The opening is very small, and the extruded mass remains adherent to 

 the corpuscle. It is much less than a twentieth the bulk of the corpuscle, 

 and it is rarely larger than one-third the diameter of the corpuscle. 

 It is slightly coloured and slightly granular, remains adherent to the 

 corpuscle, and does not show any of the " hooded " character described 

 by Dr. Roberts as the effect of tannic acid. The rent or crack in the 

 envelope or at least in the now thickened rind of the corpuscle, through 

 which the little mass is forced or ejected can often be clearly seen. 

 If such a preparation be sealed up, such buds or projections may be 

 kept for a considerable time. If a sufficient amount of the acid be 

 added other effects follow. The corpuscles begin to assume a coarsely 

 granular appearance, and the nucleus, until now unaffected, begins to 

 assume a granular appearance, but still remains pale as at first. Owing 

 to the granular condition of the hull (Dowcleswell) of the corpuscle, 

 the nucleus cannot be seen until the centre of the corpuscle is focassed. 

 Some of the corpuscles appeared to become granular without any 

 extrusion of a part of their contents. In those corpuscles which had 

 given way at one side the granular contents soon began to pass out 

 through the rent, and often the nucleus also was extruded. In many 

 of the corpuscles the nucleus was observed to be half within and 

 half without the body of the corpuscle. A distinct, highly refractive 

 envelope was traceable around the body of the corpuscle as far as 

 the break in its side, when it suddenly ceased. This envelope was 

 often traceable on one or both sides of the protruded part of 

 the corpuscle for some distance, but never completely around it. 

 The protruded mass generally remained attached to the side of 



* " Proc. Eoy. Soc," 1863. 



