330 BACTERIOLOGICAL NOTES. 



extra attention, it can without risk be used for heating thermo- 

 stats. For instance, I wanted a temperature in the thermostat 

 of 38°C.; by means of an Argand burner supplied with such gas, 

 and of a Reichert-Babes thermo-regulator, this temperature was 

 kept up, within a few tenths of a degree, for weeks. 



Bunsen's burners can only discriminately be used when working 

 with this gas, which is mostly too rich in carbon for these burners^ 

 to give a non-luminous or almost non-luminous flame. When the 

 gas gets poorer, that is, when it contains more atmospheric air, 

 Bunsen's burners can with advantage be taken for the purpose of 

 heating. Fletcher's burners, which have a large opening stretched 

 over with strong wire-gauze or perforated metal, answer best for 

 the gas, when intended for heating, say, steam-sterilisers or copper- 

 boxes. For sterilising instruments, platinum-wires, glass tubes, etc., 

 I generally used a Fletcher's burner of long cylindrical shape v^ith 

 a flattening-out at the top, which was covered with wire-gauze. 



I should add that the light of this gas from an Argand burner 

 is admirably fitted for working with the microscope. 



