BALANTIDIUM COLI INFECTION. 421 



perforated into the peritoneal cavity. Other ulcers are found scattered 

 throughout the colon. 



The situation of the ulcers hears no definite relation to the mesenteric 

 attachment. They var_y in shape, some being oval, others round, and 

 nearly all have ragged edges. The early ulcerations are clean, shallow, 

 and not injected, while the older ones are irregular in outline with their 

 bases covered with mucus and necrotic tissue. Scrapings made fi'om the 

 bases of these ulcers shoM' the presence of large numbers of the Balan- 

 tidium coli. Xo amoeba or other protozoa are observed. 



The rectum is injected, but free from ulceration. 



HISTOLOGICAL EXAMIXATION. 



The results of the histologic examination of sections of the large 

 intestine and of the mesocolic lymph glands only will be described. 



The parasites were found in all the sections of the ulcers examined, 

 being situated both in the mucosa and submucosa. The blood vessels 

 were dilated and contained many parasites. Large numbers of them 

 were also found in the nmscular layers. Some of the parasites showed 

 division forms or elongation of the nucleus. 



There appeared to be but moderate round-celled infiltration in the 

 deeper layers of the intestine, except where there were several parasites 

 grouped together. Single parasites were found in the tissues far away 

 from the ulcerations. 



Sections of an enlarged mesocolic lymph gland removed from the 

 neighborhood of the mesenteric attachment to the intestine showed 

 numerous single parasites which appeared scattered through the lymph 

 sinuses of the gland tissue and situated within the blood vessels. The 

 parasites were not found in groups anywhere in the gland. 



Plate IV fig. 1 shows eight parasites in one field. The nuclei of some 

 of the parasites are not visible. There are areas of necrosis in the 

 glandular tissue. A small area of necrosis is shown in Plate IV fig. 2. 

 The parasites are not usually situated in these areas of necrosis, but 

 sometimes single parasites are found nearby. During life the parasites 

 are almost constantly in motion. 



Sections of the intestinal ulcers and of the glands, stained by the 

 Ziehl-lSTeelson method, showed no tubercles or tubercle bacilli. 



An examination of a portion of a fresh gland crushed out on a 

 slide and stained in the same way was also negative for tubercle bacilli. 



SUMMARY. 



Case I shows particularly the earliest stages in the ulcerative process 

 caused by the Bakmiidiitm coli. (See Plate I.) Case II demonstrates 

 particulai'ly (see Plate II) the later stages of ulceration and also that 

 ill is process can proceed to the stage of perforation with resulting 



