256 THE PROTOZOA 





Flies may possibly act as transmitting agents. 



We can as a rule differentiate bacillary from amoebic dysentery by the more 

 sudden and acute onset of the former together with fever and other evidences of 

 toxaemia. 



Again the number of stools in bacillary dysentery is usually greater and the amount 

 of each stool less in quantity. The stool of bacillary dysentery is of a milky white- 

 ness from the large number of pus cells, while that of amoebic dysentery is more 

 viscid and tinged with disintegrated blood giving it a grayish green or brown color. 

 The mucopurulent mass in bacillary dysentery may be flecked or streaked with 

 blood. The therapeutic results following emetine injections are of value in diagnosis. 

 Gangrenous types of dysentery are similar whether due to bacillary or amoebic 

 infection. Chronic dysentery of bacillary origin is much like amoebic dysentery 

 clinically. 



Laboratory Diagnosis. In the fresh specimen of the milky muco- 

 purulent mass of bacillary dysentery one observes large numbers of 

 pus cells and particularly very large phagocytic cells which greatly 

 resemble amoebae. Upon staining with Gram's stain one may find 

 numerous Gram-negative bacilli in the cystoplasm of the cell. 



The large cells which resemble amoebae are often vacuolated, thus intensifying 

 the similarity. They are nonmotile, however, and do not show the small ring 

 nucleus which is so characteristic of the vegetative human amoebae. The nucleus 

 of the confusing cells is also larger, approximating one-fourth the size of the cell. 



For bringing out the nuclear characteristics of human amoebae Walker recom- 

 mends fixation of thin moist smears in sublimate alcohol (absolute alcohol i part, 

 sat. aq. sol. bichloride 2 parts) for ten to fifteen minutes. These smears are then 

 well washed with water and stained with alum haematoxylin for five minutes. The 

 nuclear characteristics are noted under etiology. With vegetative amoebae I have 

 obtained beautiful results with vital staining which can best be done by tinging the 

 faeces emulsion with a i% aqueous solution of neutral red. I have also had good 

 results by emulsifying the faeces in a drop of i or 2% formalin and then adding a 

 drop of 2% acetic acid. The mixture is then tinged with either neutral red or 

 methyl green. 



For distinguishing the encysted form of Entamceba coli one can obtain beautiful 

 results by emulsifying the faeces in Gram's iodine solution. Owing to the glycogenic 

 reaction given by E. coli, the round amoebae, with its eight nuclei stands out 

 very distinctly. 



For diagnosing the four nucleated cyst of the pathogenic amoeba one 

 gets better results with haematoxylin as this brings out not only the four 

 nuclei but the chromidial bodies as well. The use of the iodine solu- 

 tion is, however, almost as satisfactory for pathogenic cysts as for 

 nonpathogenic ones. Again where cysts are not abundant one has 

 little success in finding them in iron haematoxylin preparations which 



