382 TYPHOID FEVER 



headache, fever, and anorexia occur, followed by great restlessness, 

 delirium, vomiting, often diarrhoea, and albuminuria. Frequently 

 broncho-pneumonia supervenes, and a fatal result has followed in about 

 a third of the cases observed. The organism has been isolated from the 

 blood of the heart. The psittacosis bacillus is evidently one of the 

 typhoid group, a fact which is further borne out by the observation that 

 it may be clumped by a typhoid serum. The clumping is, however, said 

 often to be incomplete, as the bacilli between the clumps may retain 

 their motility. It differs from the typhoid bacillus in its growth on 

 potato in agglutination reactions and in its pathogenicity. 



Danysz's Bacillus and Eat Viruses. — Danysz isolated from an 

 epizootic in field mice an organism of this group, which he introduced 

 for the purpose of killing rats by originating in them through feeding a 

 similar epizootic, and several viruses of this kind are in commercial use 

 for this purpose. These have been investigated by Bainbridge, who, 

 however, finds that they owe any efficiency they possess to the bacillus 

 asrtryek and the bacillus enteritidis of Gaertner. The efficacy of such 

 agents varies, and the mortality in artificially originated epizootics is 

 from 20 to 50 per cent. Sometimes, apparently under natural conditions, 

 rats develop an immunity to those viruses, and it is doubtful whether 

 they are entirely innocuous to other animals which may partake of the 

 food containing them. 



Bactllary Dysentery. 



Dysentery has for long been recognised as including a number 

 of different pathological conditions, and within more recent times 

 amcebic and non-amoebic forms have been distinguished. Of the 

 latter, bacteria have been believed to be the causal agents, and 

 an organism described by Shiga in 1898 has been established as 

 the cause of a large proportion of cases. Shiga's observations 

 were made in Japan, and confirmatory results have been obtained 

 by Kruse in Germany, by Flexner and by Strong and Harvie in 

 the Philippine Islands, and by Vedder and Duval in the United 

 States. It is now further recognised that the epidemics of 

 dysentery which from time to time occur in lunatic asylums are 

 usually due to bacilli of this type, and in America the organism 

 has been demonstrated in summer diarrhoea in children. Bacillary 

 dysentery has been one of the most serious intestinal infections 

 of the present war. The evidence for the relationship of the 

 organism to the disease consists chiefly in its apparently constant 

 presence in the dejecta in this form of dysentery, and in the 

 agglutination of the organism by the serum of patients suffering 

 from the disease, but confirmatory evidence has also come from 

 animal experimentation and from the effects of anti-sera prepared 

 by means of the bacilli. From different epidemics a great many 

 different strains of the dysentery bacillus have been obtained, 

 but these possess common characters and are closely related to 



