- 02 — 
into kittens, it cannot be carried through more than one or two 
transfers. Indeed, it may perish in the first kittens inoculated. 
In other words, it soon fails to infect the kitten just as the rectal 
injection of kittens with tetragena-cysts falls to infect them. It is 
reasonable to suppose that strains intermediate in âge between 
adolescence and senility will yield upon inoculation a number 
of removes corresponding to the âge of the strain Werner (i), 
lias noted the failure of some strains either to infect, or to be 
carried on in kittens for more than one or two removes. 
What happens to the senile strain in the colon of the kitten 
when it lias, so to speak, run its course? It encysts. 
The colon of a kitten (weight 500 to 700 g.), particularly the 
caecum, approaches as nearly as we can at présent to a culture 
tube for E. tetragena, and in the large bowel of kittens develop- 
mental changes in the trophozoites may be observed to make 
their appearance verv much as they do in an untreated case of dy- 
sentery in man, but with this différence. On account of the 
shorter duration of the disease in kittens, and the fatal issue, it 1s 
necessary to transplant the culture to another kitten when the 
host is dying or very soon after death. In this way only can the 
âge of adolescent strains be prolonged and the appearances of 
maturity observed. B y this means, it is possible to start with 
an adolescent strain having histolytica-like characteristics, ana 
through the successive removes note the réduction in size of the 
trophozoite, the appearance of chromidial blocks in the cyto- 
plasm and the prominent karyosome and centriole in the nucléus. 
In other words, note the transformation of a histolytica-like tro¬ 
phozoite into a senile tetragena-like trophozoite. In the last re- 
move, it may be possible to detect cysts in the material contai- 
ning the precyst génération. 
If then in any case of entamœbic. dysentery, there may be 
doubt or disagreement as to the identity of the trophozoites in 
question, and as it is of course inadvisable to withhold treat- 
ment from the patient for the study of the entamœba, it is re- 
commended that rectal injection of fresh material containing tro¬ 
phozoites be made into kittens, and wet-fixed stained prépara¬ 
tions of the trophozoite from remove to remove be made, to note 
whether they correspond with E. tetragena or other form. If the 
! 
(1) Werner, loc . cit . 
