CHAPTER XIV 



BLASTOCYSTIS 



Although the organisms known as Blastocystis are 

 considered to be vegetable in nature and not pro- 

 tozoa, the confusion which has occurred in the past 

 and is likely to occur in inexperienced hands at the 

 present between these cells and protozoa makes it ap- 

 propriate to include here a brief consideration of 

 these parasites. 



Alexeieff (1911) first called attention to the real 

 nature of certain cells which had been previously 

 described as cysts of Trichomonas hominis. He clas- 

 sified them as blastomycetes and gave the name 

 Blastocystis enterocola. 



Brumpt (1912), who gave the name Blastocystis 

 hominis to the organism occurring in man, and Wen- 

 yon (1915), agreed with Alexeieff as to the nature of 

 the organism. The writer (1917) reported it as a 

 common intestinal parasite in this country, occurring 

 in all of twenty-five cases of pellagra at autopsy and 

 in the stools of 10% to 55% of several groups of in- 

 dividuals, mainly pellagrins. Barret (1921) first re- 

 ported its cultivation, in human blood serum diluted 

 ten times with 0.5% sodium chloride solution. Later 



230 



