OEIGIN OF COLORED BLOOD-CORPUSCLES. 109 



corpuscles themselves, the only difference being that its meshes are a little 

 wider than those in the globule. But the point to which I wish to draw 

 particular attention is that the granules, at the points of intersection, vary 

 very much in size. Sometimes, where they are seen along the edges of broad 

 fibers, or in the centers of very fine ones, they give it a beaded appearance. 

 At others they are so small that they are just barely appreciable. This 

 inequality in size is most probably due to a growth that is constantly going 

 on in these granules, and our finding different ones at different stages of it. 

 (See Fig. 31.) 



This process does not stop where the lump of living matter can be called a 

 granule, but it keeps on until it has converted it into what is known as a 

 corpuscle. This is accomplished by the smaller granule increasing until it 

 has become so large that the fiber can no longer contain it without showing 

 a slight bulging at the point where the granule lies. This is what gives the 

 beaded appearance just referred to. But as the bead still grows, it protrudes 

 more and more from the free surface of the fiber, until it has the appearance 

 of a small homogeneous yellowish corpuscle sticking to the side of the fiber. 

 The corpuscle is not separated from the fiber in this immature state, but 

 retains a connection in the shape of very delicate grayish spoke-like threads, 

 that can be traced directly to the granules within the fiber. This connection 

 is constant in all the different-sized corpuscles, except the very largest, and 

 in all probability is the route through which the corpuscle draws its nourish- 

 ment. We can see no differences in these growing corpuscles until they are 

 about three-quarters the size of a red blood-globule. Then, however, they 

 seem to be divided into two classes. Whether there are two sets of fibers 

 that produce the different corpuscles, or how else it is done, is more than I 

 can say; but I am sure that, at the stage I have indicated, one set become 

 more highly refracting than the other, and take more and more of the char- 

 acteristics of a red blood-globule, which they eventually become. The others, 

 however, follow the course that C. Heitzmann has described, as the ele- 

 mentary homogeneous granule takes in its development into a higher grade 

 of protoplasm. After they reach the size I have already spoken of, a cavity 

 containing a small amount of liquid forms, then similar excavations show 

 themselves, until only a frame-work of the living matter is left between the 

 vacuoles. There are communications established between these cavities, and 

 the frame-work is transformed into a net-work with thickened points of 

 intersection, which are the granules. 



With this view of the development of protoplasm we are better able to 

 understand the meaning of the vacuoled corpuscles that we so often meet 

 with. But the different sizes of the corpuscles, the different numbers of their 

 granules, and the varying conditions of their nuclei and reticula, speak for 

 themselves. They are the different stages through which an original granule 

 of the fine reticulum contained by the fibrous net-work is developed into a 

 full-grown lymph-corpuscle. 



This is further substantiated by the fact that the connection, already 

 described, between the granule that has just passed to the outside of the fiber 

 and the reticulum within it, is kept up through all sizes and shapes of cor- 

 puscles, until the full-grown condition is reached. Then, however, this attach- 

 ment is severed, and the globule passes away with the lymph stream in which 

 it has been bathed so long. This is true of both sets of corpuscles, and can be 

 shown as well in the young red as in the white. Thus we add a new proof 



