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<W,ni Jnn P ro Portion of cases of dysentery cannot be assigned to any 
finite type. Ulcers irregular m size, m depth, in character of surface or 
edges may be scattered thickly or sparsely over a varying extent of the lar<m 
intestine. In such cases the actual ulceration and secondary ulcerations 
appear to disguise the type. ' b 
1 ubercular ulcers and typhoid ulceration of the large intestine are 
commoner relatively in the tropics than in temperate climates, but present 
j difficulty m diagnosis and should cause no confusion. 
1 he Amoebae Coh has, m my opinion, a strong position as the factor 
m a large class of dysenteric lesions. The Balantidium Coh mav plav a 
part in the causation of certain other forms. In the remainder in the 
majority Or cases no animal parasites are to be found. The bacteriology 
ot the large intestine and its contents naturally has attracted much attention. 
ie number of organisms found either in the contents of the intestines on 
scraping the ulcers or m the sloughs is large, and many of them are either 
commonly or rarely found in normal intestines but are present both more 
constantly and m larger numbers in cases of dysentery. 
Amongst these organisms B. pyocyaneous is perhaps the most 
important. It is not a very rare bacillus in normal stools but appears to be 
present in the majority of cases of dysentery examined here. It is found 
not onJy m the contents of the intestines and in the sloughs, but in the depths 
ot tne ulcers and in the deep scrapings of the mucous membrane occasionally 
m tne mesenteric glands and rarely in the spleen. 
This organism has been credited with the causation of certain epidemics 
of dysentery (Hewlett’s Manual of Bacteriology , p. 439 .) The varying 
esions ouiiG associated with this organism, and the absence of anv lesion or 
symptom of disease in other cases where the organism is present^ render it 
impiobaole that it is the cause of the disease, but the increased numbers 
and the known pathogenicity of the organism in lower animals and its 
occurrence in tissues are arguments for considering it of importance as a 
secondary cause of some of the lesions or complications. The organism 
isolated from dysentery cases is indistinguishable from that isolated from 
lea . „ y lnte j stlnes o r from natural sources, and does not appear to be more 
rapidly fatal when injected into rats or guinea-pigs. 
This organism is of particular importance as it occurs in nature. It 
is also capable of conveyance by mosquitoes of certain species. The larvte 
of many species of mosquitoes breed freely in more or less diluted feces 
e\en m cess pits. Amongst these Culex fatigans, Stegomyia fasciata and 
Stegomyia scutellaris and sometimes Anopheles Rossii may be mentioned. A 
minute addition of sewage is fatal to few larvas. 
Under these circumstances as the larvae contain in their intestines 
some of the organisms present in the water in which they live, it is not 
a matter of indifference to determine which of these organisms can be found 
in the adults and passed or conveyed bv them. 
. Experiments (vide note ) showed that Pyocyaneous can be conveyed in 
this manner by certain species of mosquitoes, and that the adults may 
thetefore carry this organism to any substance on which they may alight, die 
