332 TYPHOID FEVER. 



ends which does not stain by Gram's method. // grows on all ordinary 

 media, and on potato resembles B. coli. It does not liquefy gelatin, does 

 not ferment lactose, does not curdle milk, and gives no indol reaction. The 

 parrot is most susceptible to its action, but it also causes a fatal haemorrhagic 

 septicaemia in guinea-pigs, rabbits, mice, pigeons, and fowls, the bacilli after 

 death being chiefly in the solid organs. From affected parrots the disease 

 appears to be readily communicable to man, chiefly, it is probable, from the 

 feathers being soiled by infective excrement. Several small epidemics have 

 been recognised and investigated in Paris. After about ten days' incubation, 

 headache, fever, 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 is clumped by a typhoid serum 

 i-io (normal serum having no result). The clumping is, however, said to 

 be incomplete, as the bacilli between the clumps may retain their motility. 

 It differs from the typhoid bacillus in its growth on potatoes and in its 

 pathogenicity. 



Pathological Changes in Typhoid Fever. Here we confine 

 our attention solely to the bacteriological aspects of the disease. 

 The inflammation and ulceration in the Peyers patches and soli- 

 tary glands of tJie intestines are the central features. In the 

 early stage there is produced an acute inflammatory condition, 

 attended with extensive leucocytic emigration and sometimes with 

 small haemorrhages. At this period the typhoid bacilli are most 

 numerous in the patches, groups being easily found between the 

 cells. The subsequent necrosis is evidently in chief part the 

 result of the action of the toxic products of the bacilli, which 

 gradually disappear from their former positions, though they may 

 still be found in the deeper tissues and at the spreading margin 

 of the necrosed area. They also occur in the lymphatic spaces 

 of the muscular coat. It is to be remarked that the number of 

 the ulcers arising in the course of a case bears no relation to its 

 severity. Small ulcers may occur in the lymphoid follicles of 

 the large intestine. In this regard some interesting observa- 

 tions have of late been made by Chiari and Krause, Flexner and 

 Harris, Lartigau, and Ophiils, wherein they state that these typi- 

 cal ulcerative lesions of the intestine may be entirely wanting, 

 (or so poorly developed as to be overlooked [Opie and Bassett]), 

 and yet the bacilli be found in the various organs or blood. 



The mesenteric glands, corresponding to the affected part of 

 the intestine are usually enlarged, sometimes to a very great 



