PART II. CHARACTERS AND DIAGNOSIS 83 



to have cured the patient of the E. histolytica infection but of the 

 coccidium infection as well. 



As regards the pathogenicity of the coccidium nothing can be 

 gathered from this case, for though there was also an E. histolytica 

 infection there were no symptoms attributable to either. The 

 patient had been on the Peninsula, where he had had dysentery, and 

 if the coccidium infection had been contracted there he must have 

 carried it for seven months, as he had left in September, 1915. 



As regards the oocysts from this case, development was easily 

 obtained, many of them completing their development in twenty- 

 four hours. Some of the oocysts showed a peculiar tendency to 

 abnormal development in producing only a single sporocyst con- 

 taining eight sporozoites. Developed oocysts were given in large 

 numbers to a young mouse but no infection occurred. Kittens fed 

 on developed oocysts also failed to become infected. The isospora 

 of cats is very common in Alexandria, but the oocysts are quite 

 unlike those of the isospora of man. 



(18) Iodine Cysts (I-Cysts). 

 (Plate III, figs. 12 to 17.) * 



During the early months of the year these peculiar structures, 

 with their strongly iodophilic bodies, were frequently met with in 

 the stool. They were present sometimes in very large numbers 

 and it is interesting to note that the most intense infections were 

 met with amongst a series of native prisoners we examined in 

 Hadra prison. They were present in 14'8 per cent of the prisoners. 



Examination of the daily ration microscopically did not reveal 

 any source of infection. 



The I-cysts are generally easily recognized if one employs 

 iodine. Sometimes without this it is impossible to identify them 

 certainly, as the iodophilic body may be mistaken for the chromidial 

 body of a cyst of E. histolytica. The iodophilic body, however, tends 

 to be rounded or lobed, while chromidial bodies in the E. histolytica 

 cysts are generally rod like. The I-cysts vary greatly in size and 

 shape. They may be quite small with a diameter of 7 or 8 

 microns, or large with a diameter of 15 microns or more. 

 Though most usually they tend to be circular or oval in outline 

 they may be lobed or show processes which suggest an outgrowth 

 into a filament. The single nucleus is smaller than the nucleus in 



* See inset between pages 148 and 149. 



