98 HERBERT E. DURHAM. 
the kidneys: ‘ Mitunter hatte ich auch den Eindruck, alsob 
die bekannten grossen Nierenzellen mit den Harnsduren Con- 
crementen, gar nicht das Eigentliche Epithel der Niere seien, 
sondern eher Bindesubstanzzellen, und dass die Stabchen- 
artigen Lagen das wirklich Epithel vorstellten.” 
Flemming (29) makes no mention of the wandering pigment- 
cells in his paper on the sensory cells. 
Wewill now leave the Invertebrates and return to Vertebrates. 
P. H. Stohr (No. 56) has called attention to the fact that the 
tonsils and Peyer’s patches are a site for the constant out- 
wandering of leucocytes ; for instance, he says, ‘“‘ Ueberall wo 
Anhaufungen von Leucocyten dicht unter dem Epithel liegen, 
wandern von ihnen aus zahllose Leucocyten durch das Epithel, 
und stellen, auf dessen Oberflache gelangt die Schleim- und 
Speichel-Korperchen dar.” And he remarks that though 
numerous observers have noticed the occurrence of the leuco- 
cytes in the epithelium, &c., he was the first to interpret the 
meaning of their presence. 
Hodenpyl (36), by applying carmine, melted lard, atropine 
and other substances to the surface of the tonsils in dogs, comes 
to the conclusion that soluble and insoluble bodies*are not 
readily and immediately taken up through the tonsils; the 
longest time he allowed before killing the animal was one hour, 
so that his results with intra-tonsillar injections, which were 
negative as regards transportation by leucocytes, cannot be held 
to be final. 
Armand Ruffer (53) admits that large numbers of leucocytes 
escape into the alimentary canal ; but he goes further, and says 
that some return laden it may be with carbon particles (tonsil) 
or with micro-organisms; moreover he states that the latter 
are never seen within the epithelial cells themselves. 
When I read Stohr’s memoir I made note that it would be 
of supreme interest to know whether the leucocytes he described 
were removing any deleterious matters from the animal,— 
whether, indeed, they were acting the part of scavengers in a 
manner similar to that which is described above to occur in the 
starfish, their prey, however, being micro-organisms; and 
