REPORT OF COMMITTEE ON BACTERIOLOGICAL TECHNIC 137 



substituted, the object of which is merely to assist the student 

 in filing a large number of the completed charts according to the 

 salient characteristics of the organisms described on them. Its 

 use, however, is optional; it is plainly stated to be intended for 

 index purposes only; and as it does not contain the generic 

 symbol, there is no danger of its suggesting to the novice that 

 it is intended to supplant the specific name of an organism. 



If this chart meets the approval of the Society, it will be 

 printed and will be ready for distribution at about the time that 

 this report appears in the Journal. The old charts will still 

 be kept on sale as long as there is any demand for them. All 

 the charts may be obtained from the chairman of this com- 

 mittee (address Geneva, N. Y.). A sample copy of the new chart 

 will be sent to anyone on request. 



METHODS OF PURE CULTURE STUDY 



The committee on the descriptive chart prepared two or three 

 reports on methods of pure culture study (1918, 1919, 1920), 

 which the present committee plans to keep up to date. To do 

 this, new methods are being investigated that they may be 

 published in future reports. The methods at present under 

 investigation are: methods of determining acid production from 

 sugars and other carbon compounds; methods of determining 

 diastatic action on starch; modifications of the Gram stain. A 

 preliminary publication on the first of these problems has already 

 been made this year by Conn and Hucker (1920). There is 

 nothing yet ready for publication on the other problems, further 

 than the material which appeared in the 1919 report of the com- 

 mittee on the descriptive chart. 



METHODS OF COUNTING BACTERIA 



There is no phase of bacteriological technic that has been 

 given more attention by scientific organizations than methods of 

 counting bacteria. The reason for this is the importance from 

 the public health standpoint of knowing the number of bacteria 

 in any food or drink for human consumption. It must not be 



