19 



''from rat's flesh, and a medium with the addition of a 

 " rat*s blood serum, but these have also failed to give 

 " a growth of the bacillus. Many pieces of tissues 

 *' swarming with bacilli which have been left for over 

 *' a year on appropriate media still show the bacilli 

 "staining well, but no growth has taken place." (Dr. 

 Geo. Dean in Joiirn. Hygieiie, Jan. 1905). 



By using, however, one part of yelk of egg mixed 

 with four parts of agar medium, Dr. Kmile-Weil tells 

 us {A?i7i. de I' hist. Pasteur, Dec. 1905) that he has 

 succeeded in propagating the leprosy bacillus for at 

 least a short time. Growth begins on or about the 

 fifth day and continues for about a fortnight or three 

 weeks more, and then stops, not being renewable on 

 subculture. 



If then &g% has such an invigorating influence as 

 to make a bacillus live and reproduce itself for even 

 three weeks, which by no other means can be made to 

 do so for a da}', we can gain from this some idea of its 

 power in intensifying the vigour of the easily grown 

 septic bacillus, and we can understand why Klein 

 found his cultures grown under these conditions so 

 much increased in virulence when using them for his 

 experimental inoculations. We can see how it is that 

 while more immune than seed eaters in the aggregate, 

 as I have pointed out, a large number of our wrongly 

 fed insectivorous captives die of septicaemia ; and we 

 can see how a colony of Canaries can be induced to 

 exhibit a rapidly fatal epidemic in the late stimmerand 

 autumn. 



While on this subject, I note that in Caiiaty and 

 Cage Bird Life of February 9th Dr. Butler says : — 

 " The sample of yolk is certainly not satisfactory ; it 



