22,1 Sellards and Leiva: Ammbic Dysentery 9 



area, 3 millimeters in its longest diameter, was found in the 

 lower third of the larger bowel; amoebae were plentiful in this 

 lesion. In another cat, a diagnosis was obtained three days 

 after injection; post-mortem examination at this time showed 

 one superficial ulcer, 5 millimeters in diameter, in the lower 

 third of the large bowel. In the earlier part of the work little 

 attention was given to specimens that failed to show gross 

 amounts of mucus or blood, and in some of these animals incu- 

 bation periods as long as five days have been recorded. Subse- 

 quently, the specimens were examined carefully for even minute 

 flecks of blood or mucus, and earlier diagnoses were obtained. 

 The routine was eventually established of giving saline enemata 

 daily for diagnosis, commencing the second day after the injec- 

 tion of amoebae. 



Treatment. — A few preliminary trials were made in the 

 treatment of infected cats by the subcutaneous injection of 

 emetine. It was not well tolerated and showed little or no effect 

 on the amoebae. Subsequently, emetine and the other drugs 

 tested were given in moderately strong solution by rectal injec- 

 tion. On account of the tendency to expel these therapeutic 

 enemata, the animals were always held head downward for a 

 half hour after injection. Examinations for amoebae were 

 continued daily during the early period of treatment. 



Controls. — Spontaneous recovery has been occasionally noted 

 in adult cats; it is of rare occurrence. In this work we have 

 not depended in any sense upon the uncertainties of statistical 

 evidence, but rather upon observation of the immediate radical 

 effect of therapy analogous to the establishment of the thera- 

 peutic effect of emetine on amoebic infections in man. From 

 time to time, however, we have arranged for control animals to 

 determine the severity of the various strains of amoebae used 

 in this work. 



Emetine.— Emetine is distinctly toxic for cats. Moreover, 

 repetitions of the effective therapeutic dose are tolerated only 

 for short periods. In our experiments it at once became neces- 

 sary to establish the maximum limits of the tolerated dosage. 

 This was tested chiefly by injections per rectum. Given in this 

 manner, quantities of 10 milligrams per kilogram of body weight 

 caused no loss of appetite, whereas this amount injected sub- 

 cutaneously produced nausea and vomiting almost constantly. 

 Moreover, a distinctly better therapeutic effect was obtained by 

 rectal injection as compared with parenteral administration. 



