280 APPENDIX 



Bend the end of a piece of No. 27 platinum wire about 

 10 cm. long over a bit of No. 10 wire, and fasten the loop 

 thus formed into a glass rod to serve as a handle. A 

 loopful of culture shall be interpreted as meaning all the 

 fluid that the loop can hold. That is, the fluid shall form 

 a bi-convex body and shall not be simply a film covering 

 the space in the loop. 



The standard fermentation tube shall be a tube 1.5 cm. 

 in diameter, bent at an acute angle, closed at one end and 

 provided with a bulb at the other which is large enough 

 to receive all the liquid contained in the closed portion. 

 The length of the closed end of the tube shall be about 

 14 cm. The bulb shall have a diameter of about 3.8 cm. 



INCUBATION 



There shall be two standard temperatures of incubation — 

 20° C. and 37° C, the first corresponding to ordinary room 

 temperature, the second to blood heat. The temperature 

 of the incubators shall not be allowed to vary from these 

 two standards by more than 1° C. in either direction. 



The atmosphere of the incubator shall be kept moist, 

 preferably near the point of saturation. The incubator shall 

 be ventilated so as to insure a reasonably good circulation 

 of air in order to prevent the accumulation in the incubator 

 of gases which might be prejudicial to the development of 

 the bacteria. 



No definite period of incubation can be prescribed which 

 will be suitable for all the work of species determination, 

 but in reporting results the period used shall always be 

 stated and form a part of the report. General statements 

 as to the necessary periods will be found in connection 

 with the principal tests. 



