r 



MODE OF INGESTION 69 



full of microbes" therein. Similar observations have 

 frequently been made both before and after that time. 

 It has also been repeatedly noticed that in sections of 

 the epithelium over lymphoid collections small glandu- 

 lar lymphocytes are to be seen between the epithelial 

 cells. It will be seen in Fig, 1 that such glandular 

 lymphocytes may contain bacteria. This is frequently 

 the case. May not glandular lymphocytes wander to 

 the surface, surround bacteria, and return with their 

 prey to the retiform tissue ? To this process I would 

 apply the term phagotaxis. A strong piece of evidence 

 in favour of this theory is to be found in the fact that 

 almost all (if not quite all) the bacteria seen in the 

 epithelial layer lie within glandular lymphocytes. I 

 have only seen small glandular lymphocytes in the 

 epithelium, yet large glandular lymphocytes also 

 contain bacteria. Possibly there is a transference of 

 bacteria, or, as Ruffer described, the large glandular 

 lymphocytes may engulf small glandular lymphocytes 

 with their contained bacteria. I have seen many dead 

 glandular lymphocytes in sections. 



By this theory glandular lymphocytes found astray 

 in the alimentary lumen would be looked upon as the 

 few which had failed to wander back into the lymphoid 

 tissue. 



The hypothesis of phagot^-xis also derives strong 

 support from the evidence in favour of the ingestion 

 of inert particles by the subepithelial lymphatic glands. 

 For besides bacteria these glands may be seen to con- 

 tain brownish or blackish granules of apparently inert 

 matter. These granules are probably carbon particles 

 for the most part. They were so described by Ruffer, 

 who pointed out that they were a much more prominent 

 feature in the dog's tonsil than in the rabbit's, a fact 

 he associated with the mouth breathing habit of the 

 dog. Sometimes these granules are sharply angular. 



