Parasitic Protozoa. 159 



sues as the Hypoderma bonis of the ox might be mentioned, 

 but the pathological bearing of these is practically insigni- 

 ficant when compared to the effects which some of the Pro- 

 tozoa are capable of producing. The great impetus given 

 to investigators in morbid processes by Pasteur in his clas- 

 sical fermentatoin experiments and bacteria discoveries as 

 causes of diseases, has also resulted in the discovery that 

 some of the diseases so fatal to the human race are due, not 

 to bacteria but to Protozoa. Among those more definitely 

 ascribed to these organisms may be mentioned Dysentery, 

 Malaria and Cancer. 



Tropical Dysentery often occurs epidemically and is an 

 extremely fatal disease. It is usuall} T confined to the Trop- 

 ics but cases are often met with in temperate regions. 

 Most of these have contracted the disease in the coun- 

 tries where it is more or less endemic. The organism caus- 

 ing it has been termed by Losch, Amoeba Goli ; by Council- 

 man and Lafleur, Amoeba -Dysenteriai. It has been described 

 as " A unicellular, protoplasmic, motile organism from ten 

 to twenty micromillimetres in diameter, consisting of a clear 

 outer zone ectosarc and a granular inner zone endosarc, 

 containing a nucleus and one or more vacuoles." It appears 

 to be taken in drinking water and in the alimentary tract 

 sets up more or less definite lesions. These consist of cede- 

 matous and infiltrated areas which soon become necrotic and 

 slough leaving undermined ulcers which may perforate the 

 intestinal wall. The amoeba has been found constantly 

 present in the invading wall of the ulcer, of the surround- 

 ing lymph spaces, or blood vessels. The result of these 

 lesions is a prolonged and frequently bloody flux which 

 may terminate fatally. Sometimes the organism, probably 

 through the blood or lymph channels gains access to the 

 liver with the result that necrotic areas and abscesses 

 form. These may discharge their contents either in the 

 abdominal or thoracic cavity and are very fatal in their 

 termination. The abscesses invariably contain large num- 

 bers of the organisms. What the life history of this crea- 

 ture is outside of the host is unknown. Its presence in 



