298 THE ZOOLOGIST. 



following days. On dissecting the first I found the typical 

 condition of Koch's " mouse -septicaemia" (Mduseseptikdmie). 

 The culture from the organs affected confirmed the diagnosis. 

 Dissection and culture showed that the other two mice had also 

 died of this " mouse-septicaemia." During the next few days three 

 more died in the same case, all from the same cause. According 

 to the attendant's report, at least fifteen mice died, and all 

 probably from the same disease. It is highly probable that the 

 infection was conveyed through the digestive system, as the first 

 mice found dead had been partly devoured. We did not discover 

 the cause of the appearance of the epidemic in the cage. Nothing 

 had been done in observing the bacilli of " mouse-septicaeuiia." 

 When the infected and diseased animals were removed, it 

 ceased. 



It is of special interest to find the bacillus which Koch 

 employed to produce disease among mice by inoculation, 

 spontaneously producing an epidemic disease among mice in 

 captivity. 



The second much more important and extensive epidemic 

 broke out in October, 1890. There were ten mice in the first 

 cage, and forty-five in the second. All the deaths occurred in 

 the second cage. The ten mice in the first cage were fed and 

 treated in exactly the same way as those in the adjoining cage, 

 but remained quite healthy. 



The attendant noticed that several mice died about the 7th to 

 the 10th of October; and by the 19th eight of the forty-five mice 

 were found dead in the cage. I was not told that the mice were 

 dying till the 19th October, when another large mouse was found 

 dead. I immediately gave orders that all dead mice should be 

 given to me for examination. On Oct. 20th two mice (1 and 2) 

 were found dead, and a mouse which appeared diseased was 

 isolated in the morning, und died in the afternoon (3). 



On the morning of Oct. 21st three more mice were found 

 dead (4, 5, 6), -and five apparently diseased ones were isolated. 

 In the afternoon an old one (7) and a young one (8) lay dead in 

 the cage. 



On the 23rd a young diseased mouse was isolated. It died 

 in the afternoon (9). 



On the morning of the 25th one of the isolated mice died 

 (10). In the afternoon two more died (11 and 12). 



