396 TYPHOID FEVER 



lactose has been observed. Here again much information may 

 be obtained from the agglutinating properties of the serum. 

 It has also been found that the serum of persons suffering from 

 meat poisoning sometimes clumps the typhoid bacillus, though 

 a higher concentration is required than in the case of Gaertner's 

 bacillus. The Gaertner group of organisms is very pathogenic 

 for laboratory animals. Often, whatever the channel of infec- 

 tion, there is intense haemorrhagic enteritis, and very usually 

 there is a septicaemia with the occurrence of serous inflammations ; 

 the bacilli are recoverable from the solid organs and often from 

 the blood. In man, as the name of the bacillus indicates, the 

 symptoms are centred in the intestine, where there is usually 

 marked inflammation of the mucous membrane, sometimes 

 attended with haemorrhage into it ; evidence of a septicaemic 

 condition may also exist. Infection may take place by the 

 bacillus itself, and here the illness usually appears within 

 twenty-four hours of the food being partaken of, but symptoms 

 may appear almost at once, in which case they are no doubt due 

 to the action of toxins ; here it is important to note that the 

 poisons formed by this group of organisms are relatively heat- 

 resisting, so that boiling for a time does not destroy the toxicity. 

 It is stated that the b. Gaertner occasionally occurs in normal 

 faeces. 



The Bacillus Suipestifer (or vErtryck) was isolated from cases 

 of hog-cholera, though this disease may be really due to a filter- 

 passer. It has been found in the intestine of normal pigs and 

 may originate meat poisoning, especially where pork is the 

 substance at fault. It has the common characteristics of the 

 group and can only be distinguished from other members by 

 serological methods. It shows specially close resemblances to 

 b. paratyphosus B, and to differentiate it from this organism the 

 method of absorption or that of complement fixation must be 

 employed. 



The Psittacosis Bacillus. When parrots are imported from the 

 tropics in large numbers, many die of a septicaemic condition in which an 

 enteritis, it may be haemorrhagic, is a marked feature. There is intense 

 congestion of all the organs and peritoneal ecchymoses. From the 

 spleen, bone marrow, and blood there has been isolated a bacillus having 

 the group characters, except that here also an effect on lactose has 

 been described. The parrot is most susceptible to its action, but it 

 also causes a fatal hsemorrhagic 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, 



