[ 778 ] 



of the other e*tuve the water is mixed with calcium chloride, 

 the mixture having, a higher boiling point than 104 C. 

 The tube is in continuation with a narrower part which ends 

 in a U tube, through which the larger supply of gas passes. 

 When, however, the oil is hotter than 104 C. the mercury 

 expands and drives the water before it so high that the 

 passage of the gas through the U tube is completely cut off, 

 the flame goes down, and the temperature of the oil goes 

 down to 104 C. It cannot go down lower, however, for the 

 water would go down also in the U tube and allow of the 

 passage of some gas through the tube, which would make 

 the flames larger, and the oil thus get hotter. The intercep- 

 tion of gas at the U tube would have put out the gas 

 altogether, and made the oil go down in temperature again, 

 but for a constant supply of a very small quantity of gas 

 directly to the burner through another India-rubber tube, 

 which keeps the flames just burning. Very hot oil is poured 

 in the jacket. When the thermometer after a time indi- 

 cates a temperature of exactly 104 C., a mixture of water 

 and calcium chloride is poured into the u tube, so as just 

 to intercept the passage of the gas. The etuve keeps itself 

 adjusted after this. 



1.343. Preparation of Anthrax Vaccines. Besides Pas- 

 teur's vaccines for anthrax, there are two more that are 

 effectively employed as a protection against this plague. 

 These are prepared in th-e Government Veterinary College of 

 Lyons. The modes of attenuation employed were discovered 

 by M. Chauveau, the former Director of the College. 



1.344. The virulent virus is taken from a recently dead 

 animal, with an ordinary sterilized pipette, in the usual man- 

 ner, to be fully described hereafter in connection with that 

 for Pasteur's vaccine. This is sown in a sterilized flask con- 

 taining proved broth, and the culture of bacilli is allowed to 

 go on in the flask by leaving it for 20 hours in an etuve regu- 

 lated at a temperature of 42C. When this period of time 



