22 On the Cellular Structure 



unfold the creases in its walls, the globule behaving as you might 

 expect a bladder half full of water to do if you stepped firmly upon 

 its centre ; on continuing the process, however, no rupture of the 

 walls could be detected, the contained fluid appearing to rapidly 

 transude through its former envelope, which, on the needle being 

 removed, collapsed to perhaps half its former size, and presented 

 the aspect of a loose bag, almost without coloured contents, sur- 

 rounding the nucleus. These changes were also examined under the 

 •^-inch objective, giving a power of almost 1200 diameters, by 

 adjusting its component lenses, for a covering glass shghtly thinner 

 than that actually employed, and then cautiously screwing down 

 the objective, so as to compress a blood disk beneath it ; under 

 this finely graduated pressure and high magnifying power, the 

 apparent expanding of fold after fold, in the plicated wall of a per- 

 viously wrinkled corpuscle, became strikingly evident. After 

 tinting the external portion of the red disk with anihne solution, and 

 then applying considerable force to the covering glass, either by 

 means of a mounted needle under a low power, or, with the ex- 

 tremity of a high objective itself, so as to empty out all the hsemato- 

 crystallin, the shrivelled envelope could be traced after the 

 removal of the pressure closely applied to the surface of the nucleus, 

 and under such circumstances occasionally presented an obscurely 

 granular appearance. 



Sometimes a few of the corpuscles situated near the edge of the 

 thin glass, and therefore most exposed to the action of the air, 

 appeared, after three or four hours, to become cracked in various 

 places from the circumference to their centre ; those fissures seem 

 to involve not only the cell contents, but also the supposed cell 

 wall ; although at first sight this phenomenon may be deemed 

 inconsistent with the older theory, in regard to the structure of 

 the red disk, yet I think that it can be explained by supposing 

 that the haemato-crystallin had in these cases undergone a sort of 

 troubled crystallization, causing it to form a mass of tolerable 

 firmness, which split into fragments as it became dry, and at the 

 same time cracked its membranous envelope, just as a piece of 

 muslin frozen fast to a lump of ice is sometimes broken with the 

 fracture of the surface to which it is attached. In some instances, 

 the delicate and transparent cell waU could be detected in the flaw 

 of the haemato-crystallin, its outer edge showing a concave line 

 across the peripheral extremity of the fissure. 



The addition of water to the fresh blood gave very interesting 

 results, and occasionally afforded an admirable proof of the exist- 

 ence of a membranous envelope. The first effect of diluting the 

 liquor sanguinis was to increase the thickness of the corpuscle, and 

 under its further action the disk gradually became less elongated, 

 until it assumed a spheroidal form, the coloured portion being 



