163 PARASITIC PROTOZOA POUND IN S. AFRICA. 



observations are being continued. The horses suffered from intes- 

 tinal disorder commonly called "colic," and at times of evacuation 

 of large numbers of the ciliates the horses suffered greatly from 

 flatulence and passed much gas. The numbers of Cycloposthium 

 in a measured quantity of faecal ooze were counted daily. Liquid 

 ooze was obtained by pressing a quantity of freshly shed manure. 

 The ooze, being too thick for counting parasites, was diluted. One 

 part of ooze, thoroughly mixed with four parts of sterile water, 

 has usually proved suitable. The counts of Cycloposthium were 

 obtained in each case by using one-fifth c.c. of ooze thus diluted, 

 made into fresh thin preparations under coverslips, the organisms 

 being counted with the aid of an Ehrlich ocular. For the period 

 Mav 1 to June 13, 1921, the daily numbers ascertained were 164, 

 85/50, 40, 11, 0, 0, 3, 8, 22, 35, 55, 194, 217, 136, 133, 82, 15, 

 5, 0, 5, 18, 5, 3, 3, 0, 0, 342, 284, 1116, 724, 515, 309, 112, 67, 

 12, 0, 0, 16, 126, 114, 157, 194, 317. The three successive maximal 

 periods were of 14, 16 and 14 days respectively. Counts over other 

 periods gave similar results and the average periodicity of maximal 

 crops of Cycloposthium was about 14 days. Coincident with the 

 increase in the number of the ciliates there was an increase in the 

 softness and pulpiness of the faeces of the horses. When the num- 

 ber of ciliates was very low or zero, the faeces were formed and 

 hard. As the number increased, the faeces became softer and looser 

 until at periods of maximum crops of ciliates the faeces were prac- 

 tically diarrhoeic in character. Other horses kept and fed under 

 identical conditions showed no symptoms, nor did they harbour 

 Cycloposthium. In one case a horse became infected and was very 

 "colicky." Cycloposthium was found and the source of infection 

 traced to a dirty stable broom used in the infected stable. 



Referring to my remarks in previous communications (1919, 

 1920) regarding Balantidia in pigs, it is of interest to state that 

 during 1921 of the large intestines of 33 pigs examined in Johan- 

 nesburg 14 were found to be infected with Balantidium coli. The 

 caecum and the rectum were the sites of infection observed. In 

 the caecum active motile forms of the ciliate were found, while in 

 the rectum both motile forms and cysts were seen. Red blood 

 corpuscles were observed inside the motile ciliate Balantidia from 

 three of the pigs. In two of these the Balantidia which had 

 ingested red blood corpuscles were present in the caecum, and in 

 the third pig the Balantidia containing red blood corpuscles were 

 present in the caecum and in the rectum. Further, in the case of 

 one of the pigs in which motile ciliates were present in the caecum, a 

 "pin-point" ulcer was found in the wall of the caecum. The 

 relation of Balantidium coli to the pig is usually considered to be 

 that of a commensal, but should it reach man it is less in harmony 

 with its host, and changes or is forced to change its mode of life 

 by ingesting more red blood corpuscles and working its way into 

 the host's gut-wall, and so it becomes pathogenic in man. 



Paraisotricha colpoidea Fiorentini was seen in relatively few 

 numbers in the fresh caecum of one horse that had died from horse 

 sickness virus at Onderstepoort. 



