294 BACILLI OF THE TYPHOID GROUP 



BACILLUS OF DANYSZ. 



A bacillus either very similar to or identical with the Bacillus 

 typhi murium was discovered by Danysz, and is known by the name 

 of the discoverer. It has been much exploited commercially as a 

 destroyer of rats. According to Rosenau's experiments the so-called 

 Danysz-virus and similar preparations are worthless in the destruc- 

 tion of rats. 



PSITTACOSIS OR SEPTICEMIA OP PARROTS. 



This disease of African and American species of parrots, also called 

 mycosis of parrots, is of interest because it is claimed that it is com- 

 municable to man, producing in persons exposed to the contagion a 

 frequently fatal type of pneumonia. The disease in parrots is char- 

 acterized by prostration and diarrhea, and in its course small grayish- 

 wnite nodules are formed in the liver and other internal organs. The 

 bacteriology of the disease has been studied by Nocard, who describes 

 a bacterium belonging to the colon group as its cause. It grows 

 both aerobically and anaerobically on the ordinary culture media. 

 In bouillon it grows rapidly in the incubator, clouds the medium 

 uniformly, and forms a thin surface pellicle which sinks to the bottom 

 of the tube on slight agitation. On gelatin it forms light bluish, 

 shining, and also darker opaque porcelain white colonies. It grows 

 also on agar, on potatoes, in milk. Gelatin is not liquefied, lactose 

 not fermented, and milk not coagulated by it. The bacillus of 

 psittacosis, therefore, in cultures acts more like the typhoid or hog- 

 cholera bacillus than the Bacillus coli. According to Dupuy's 

 statistics, as quoted by Nocard, seventy persons living in Paris during 

 the years 1892 to 1897 contracted psittacosis from parrots, and 

 twenty-four of these died. It is believed that the disease is generally 

 contracted by persons kissing the sick parrots or by otherwise coming 

 in too close contact with them. The first cases of psittacosis pneumonia 

 in man were probably observed by Ritter in Switzerland in 1879. 

 Palamidessi observed five cases in one family in Florence. Leich- 

 tenstern, who saw some cases of this peculiar pneumonia in man in 

 Germany, doubts that they have their origin in parrots suffering 

 from psittacosis. 



BACTERIUM PULLORUM. 



Occurrence. An epidemic disease with a very high mortality occurs 

 among very young chicks recently hatched. The young fowls first 

 show a loss of appetite and sluggishness, the feathers become ruffled, 

 and diarrhea appears; the droppings are of a whitish color. The 

 disease is known under the name of white diarrhea of chicks. As 



