igS RESEARCH IN PROTOZOOLOGY 



culture to the syringe. When fecal material is used the only pre- 

 requisite is that it he sufficiently fluid to pass through the catheter. 

 Amoebae in feces of infected kittens are more effective as inoculum 

 than are amoebae grown in culture. Kessel (1927) recommended 

 that the kitten be held head downward for about fifteen minutes 

 after treatment. Other workers have suggested the closing of the 

 anus by a plug of cotton coated with collodion or a purse-string 

 ligature. Both of these operations cause constant annoyance to 

 the kitten until it finally removes the obstruction. If the injection is 

 skillfully performed the animal may be subsequently left undis- 

 turbed. Kittens inoculated as described above usually become 

 positive within three to five days. Loss of weight and diarrhea are 

 the first manifestations but trophozoites oi E. histolytica must be 

 demonstrated in the feces to establish the diagnosis. It is much 

 easier to detect the living amoebae in wet preparations than to 

 locate them in stained smears. At room temperature, 25° C, the 

 amoebae will live a number of hours and, if each kitten is in 3 

 separate cage, fecal samples may be collected from the latter. 

 Under other conditions a warm enema of normal salt solution 

 must be given to secure suitable material. The method of inocu- 

 lation after laparatomy, referred to above in the review of the 

 literature, involves a surgical operation. Skill to carry out the 

 above can be acquired only by special training. A description will 

 therefore not be attempted in this article. 



RECORDING AND PRESERVING OF DATA 



Naturally the objectives of any given series of experiments will 

 determine the nature of the experimental data to be emphasized, 

 but the following suggestions are of general application. The value 

 of well preserved tissue with proper data pertaining thereto cannot 

 be fully estimated at the time when taken. They frequently have a 

 bearing on problems of the future. For example : the detection of 

 the living amoebae in a wet smear satisfies the requirements of a 

 positive fecal diagnosis, but one may wish to know at a later 

 date whether pathological changes were detectable in the nuclei of 

 these amoebae. A well-stained smear will serve to determine this 

 point and also to confirm the accuracy of the diagnosis. Cytological 

 details are best brought out with Heidenhain's iron-hematoxylin. 

 Directions for preparing and using this stain will be found in 

 another chapter. It cannot be too strongly emphasized, however, 



