ON WANDERING CELLS IN ECHINODERMS. 89 
pigmentation being largely due to a deposit of the particles 
inhaled: besides the lungs, the bronchial lymphatic glands 
are found to contain collections of similar material; and this 
has been brought there by the industry of leucocytes which 
have ingested the particles, gained the lymph-stream, and so 
arrived at the glands (vide Ziegler, No. 62, ii, p. 673; Klein, 
No. 38). 
‘Many of the particles, however, remain permanently in the 
walls of the lymph-vessels, and of the alveoli of the lung, and 
cause the pigmentation seen after death: some, again, may be 
got rid of by expectoration. 
Again, in the case of tattooing (Ziegler, i, p. 128), the lymph- 
glands corresponding to the parts operated on are found to 
contain particles of the material used. In such pigment-con- 
taining lymph-glands the pigment remains permanently, the 
tissue often undergoing some fibrous change. In blood effusions 
cells filled with blood-corpuscles occur in the lymph-glands, 
the hemoglobin becomes altered, and eventually the resulting 
pigment may be absorbed and disappear (Cohnheim, ‘ Allgem. 
Path.,’ New Syd. Soc., i, p. 408). In such cases the pigment 
remains in the system—that is, it is not carried to the exterior 
directly. In some instances, however, insoluble granules seem 
to have been entirely got rid of, for in dogs and frogs (Ziegler, 
62, i, p. 40), when particles were injected into the blood circu- 
lation, some were actually got rid of through the pulmonary 
alveoli and sputum, some were found in the bile, the path by 
which they got there not being quite clear; and further in 
dogs some were found in leucocytes in the tonsils, by which 
they were being carried to the free surface through the epithe- 
lium. We shall refer again to the tonsil, but it is right to 
mention here that Armand Ruffer (No. 53) describes the 
presence of carbon particles within leucocytic cells in the dog’s 
tonsil, and he regards these as coming from the free surface 
into the organ. Which end of the balance contains the true 
and which the false weight is as yet doubtful. Hence it would 
be inadvisable, perhaps, to make any comparison with the 
process above described to occur in Asterias rubens, whereby 
