1891.] Wandering Cells in Animal Bodies. 515 
inorganic particles, which they cover by their protoplasm, and 
retain, so that they cannot do harm to the animal. I have been 
told that in men whose arms have been extensively tattooed 
with India ink, the small lymph nodules in the axilla are some- 
times very deeply pigmented. As has been said, these nodules 
are made up principally of amoeboid lymph leucocytes, and when 
the lymph, carrying particles of ink, passes through them, the 
phagocytes pick up the pigment granules and retain them. 
Again, it has recently been stated that if a bit of sponge be 
inserted under the skin of any of the mammals it will in a few 
days entirely disappear ; and if, before this occurs, it be taken out 
and examined, it will be found to be full of phagocytes which are 
destroying it. i 
Osler, in a recent address on the subject, says that in the 
sputum of smokers there appear cells from the alveolar epithe- 
lium of the lungs, which are evidently amæboid, carrying parti- 
cles of carbon. The same is said to be the case with miners who 
inhale coal-dust, and that these carbon-laden cells may continue to 
appear for months after a man has ceased to expose himself to 
the dust. It need not be said that such unusual work put upon 
the lungs might lead to serious results. 
In the process of digestion in mammals, fats are emulsified, or 
broken into small particles in the intestine, and are transferred 
bodily through its wall into lymph vessels. In this it differs 
from the transfer of a dissolved salt through a membrane by 
dialysis, and the numerous leucocytes in the intestinal wall are 
known to carry the fat particles through the lining epithelium 
into the lymph capillaries beneath, where they disintegrate and 
liberate their load. It is not definitely understood how the fat 
particles are taken in, but it is supposed that the phagocytes push 
out processes or pseudopodia to the surface of the ers 
epithelium cells, and then surround them, and draw them inward. 
There seems to be a tendency to divide the functions of leuco- 
cytes into those which are normal, and abnormal. For example, 
in the last instance mentioned, the work done by amoeboid cells 
is said to a natural or normal one, and it undoubtedly is m On 
the other hand, the attack made upon the bit of sponge intro- 
