THE HUMAN NASAL POLYPUS 275 



the fact that the path to the air passages is impeded 

 to some extent. The first polyp reported from India 

 was about the size of a large pea. It had a short stalk 

 by which it was attached to the mucous membrane 

 of the nose. The structure has been compared with 

 that of a raspberry, for it was red in colour with a 

 number of small, whitish spots upon its surface. 

 When the tumour was cut, a number of whitish 

 specks could be seen within. These proved on ex- 

 amination to be cysts of a protozoal parasite. The 

 cysts vary considerably in size. Each possesses a 

 cyst wall, which varies in thickness in different cysts. 

 Its outer wall is always firm and distinct, the inner 

 limit being much less definite at times. Each cyst 

 examined microscopically is seen to be filled with 

 numbers of spherical or oval bodies, showing every 

 gradation between small ones at the periphery to 

 large ones towards the centre. Roughly, three zones 

 of parasites can be distinguished, a peripheral set 

 consisting of the youngest parasites in the cyst, an 

 intermediate group, and a central oldest zone, each 

 merging naturally into the other. 



The youngest forms are difficult to detect. They 

 are small, granular masses, and may be either ovoid 

 or irregular, even amoeboid in appearance. They 

 are the early trophozoite forms. Such forms increase 

 in size. Their outer layer becomes firm, and gradu- 

 ally small bodies with definite contours are differen- 

 tiated. As each is destined to give rise to many 

 spores, it is termed the pansporoblast. The forma- 

 tion of pansporoblasts progresses at the expense of 

 the peripheral layer of protoplasm, which, however, 



