30 IMMUNITY IN HEALTR 



Cat (Felis Domestica), 



Leopard (Felis Pardus), 



Cow (Bos Taurus), 



Rabbit (Lepus Cuniculus), 



Civet (Viverra Civetta), 



Tasmanian Devil (Dasyurus Sp.), 



Opossum (Didelphys Carnivora). 

 Many intermediate forms are to be found in other 

 animals. 



The nasopharyngeal tonsil has been traced in mam- 

 mals, birds, and even reptiles, according to St. 

 Clair Thompson, quoting Alagna (1902). In man the 

 lymphoid tissue principally hangs from the roof and 

 posterior wall as already described. This is not the 

 case in all animals. In the sheep family the surface 

 of the hinder part of the septum nasi is ridged and 

 nodulated by the presence of masses of lymphoid tissue 

 constituting the septal nasopharyngeal tonsil. 



Excellent specimens, presented by H. Seccombe 

 Hett, Esq., illustrating some of the above points, may 

 be seen in the museum of the Royal College of Surgeons, 

 London. 



The Ileal Group of lymphatic tissues is probably of 

 widespread occurrence. Huntington (1903), however, 

 states that both aggregated and solitary follicles only 

 occur together in mammals, and that solitary follicles 

 alone only occur in birds. The aggregated patches, as 

 in man, occupy the side of the bowel remote from the 

 line of attachment of the mesentery. Stapley (1911) 

 states that in pigs a continuous elongated patch six 

 feet' in length is to be found. In the rabbit a specially 

 large collection of lymphoid tissue is found stretching 

 for an inch or so immediately above the ileo-caecal 

 valve. It sometimes nearly encircles the bowel at the 

 extreme end of the ileum. Immediately beyond the 

 ileo-caecal sphincter is another patch of about the same 



