STRUCTURE OF COLORED BLOOD-CORPUSCLES. 69 



shorter continuance, suddenly disappear. They are either empty 

 or else contain one or more granules. 



Soon after the corpuscles are studied, sometimes from the 

 first, a difference is noticeable as to the intensity of their colora- 

 tion $ some are paler than others. Gradually a larger number of 

 corpuscles become pale, and the degree of paleness, too, increases. 

 There is a great difference in respect to the rapidity of "paling" 

 of colored corpuscles, in blood taken from different persons, even 

 in blood of the same person taken at different times, and with 

 different strengths of the admixed solution of bichromate of 

 potash. 



Usually, in blood of healthy persons, examined as I have 

 described, in about an hour from the time the drop of blood is 

 placed on the slide, a few of the corpuscles that are least deeply 

 colored appear to have become somewhat granular in their inte- 

 rior. Focusing shows that this is not the optical illusion alluded 

 to in the case of knobbiness of the surface. 



Soon the granules or dots seem more distinct ; short, conical 

 thorns, or more delicate spines, appear to issue from one or two 

 of the largest of them ; and, on close inspection and focusing, 

 some appear to be connected by irregularly concentric filaments. 

 In the course of five minutes more, a complete net- work is dis- 

 tinctly seen in the interior of one or more corpuscles, and what at 

 first appeared to be granules turn out to be thickened points of 

 intersection of the threads forming this reticulum. These points 

 or dots are irregularly shaped, and vary in size. (See Fig. 25.) 



FIG. 25. THE STRUCTURE OF FIVE COLORED BLOOD-CORPUSCLES. 



In the first, there is seen an encircling band of uniform thickness, in which are inserted 

 numerous threads of a net- work ; a number of knots are in the interior, which are seen to 

 be the points of intersection of threads constituting a net-work ; in the lower portion of the 

 disk there is a larger knot, which may be called a nucleus. In the fifth corpuscle the com- 

 plete net- work structure is best seen ; in this corpuscle there is seen at the periphery, instead 

 of an encircling baud, a number of knots united by threads, having the appearance described 

 as beads, eacli a little separated from its neighbors on the string. The second corpuscle 

 shows the net- work and encircling band, as the majority of corpuscles show them. In the 

 third, a lighter band is seen, and an irregular flap, produced by either indentation or protru- 

 sion, or both. The fourth exhibits a large flap or knob at its lower portion, with a stretched or 

 extended net-work. 



Radiary threads of the net- work terminate at the periphery 

 of the corpuscle, either with thickened ends connected by threads 



