THE LEUCOCYTES IN ORGANIC FUNCTIONS. 669 



This is well illustrated in the annexed plate from a valuable 

 study of the subject by G. L. Gulland, 4 by Fig. 1, a hyaline 

 leucocyte from a newt's blood. These cells are undeveloped 

 and their protoplasm does not as yet show "threads!" But 

 their nucleus is clearly supplied with them even at this early 

 stage a feature which suggests that the nucleus is an au- 

 tonomous structure. This is further sustained by the pres- 

 ence, in the perinuclear portion of the cell, of a small body, the 

 astrophere, shown in Fig. 7, another undeveloped, or "hyaline," 

 cell. This astrophere is likewise present in fully developed 

 leucocytes, as may be seen in Figs. 10, 12, and 16. Each cell 

 may, therefore, be said to contain two functional centers, each 

 supplied with its net-work of fibers or threads. 



Heidenhain is stated by Gulland to have found that "the 

 granules are arranged radially to the astrophere, with the 

 smallest granules next the sphere, the largest at the periphery." 

 This is exemplified with especial clearness in Figs. 10 and 16, 

 and if the threads, or fibers, are traced from the center of the 

 astrophere, the gradual increase in size of granules as the 

 periphery of the cell is approached is clearly indicated. Hei- 

 denhain also concluded, a feature fully confirmed by Gulland, 

 that "there are never any granules within the astrophere it- 

 self." It thus becomes evident that while the nucleus is an 

 autonomous structure, the same may be said of the astrophere. 

 In other words, a leucocyte seems to be supplied with two in- 

 dividual, though doubtless correlated, functional systems: (1) 

 the nucleus per se, which contains a net-work of fibrils and 

 granules; (2) the astrophere, which represents the center of 

 the cellular net-work of granule-laden fibrils. 



As may be seen in the numerous cells represented in 

 Gulland's plate, which cells have been drawn by him with the 

 utmost care and fidelity to microscopical appearances, the fibers 

 in the nucleus divide the latter into several irregular areas, 

 while the radiating net-work of which the astrophere is the 

 center forms relatively regular spaces. The fibers in both 

 structures run to their external boundaries, however, precisely 

 as if they were attached to the external limiting membranes of 



* G. L. Gulland: Journal of Physiology, vol. xix, 1896. 



