166 PARASITIC AMOEBAE OF MAN. 



poses a large proportion of susceptible animals will 

 develop the disease. 



The uniformly negative results reported by some 

 authorities are explained by the fact that they were 

 working with the harmless Entamceba coli or with 

 feces containing only the vegetative stages of Enta- 

 mceba histolytica. 



Personal Observations. I have already detailed 

 the negative results obtained in kittens by feeding 

 experiments and rectal injection with feces contain- 

 ing the vegetative and encysted stages of Entamceba 

 coli. These experiments have been repeated, using 

 the feces of dysenteric patients containing both the 

 vegetative stages and the spores of Entamoeba 

 histolytica, with the result that 66 per cent, of the 

 kittens experimented upon by feeding developed 

 typical amoebic dysentery, while 50 per cent, of those 

 in which rectal injections were used developed the 

 disease. Control tests were made with the bacteria 

 occurring in the feces and with feces containing Enta- 

 moeba coli. 



Rectal Injections. This is the method which has 

 been employed by most investigators of this subject, 

 but it is not as successful as the feeding experiments, 

 only 50 per cent, of the animals experimented upon 

 developing the disease. Half-grown kittens were 

 used, about 5 c.c. of feces containing amoebae being 



