ABSTRACTS 89 



The amount of blood to be added depends upon whether or not the 

 meningococcus has become accustomed to the medium. In trans- 

 planting from another medium to this potato blood agar, a little difficulty 

 may be experienced in getting the cultures started upon the new sub- 

 stratum. For this reason a large amount of the growth (not over twenty- 

 four hours old) should be transferred and about 20 per cent of blood be 

 added to the medium. In making the inoculation the culture should 

 be rubbed slightly into the surface. This is incubated at 37.5°C. for 

 about two days and then transplanted again to the potato extract 

 agar containing just sufficient blood to permit growth — that is, about 

 5 per cent. Subsequent transplantation need not be made more often 

 than every thirteen to fifteen days or longer, when kept at 37°C., 

 provided that the cultures do not become too dry. In the case of 

 cultures paraffined or sealed to prevent drying, a fair growth may be 

 obtained after six weeks. 



Pasteurization Applied to Mold Spores. Charles Thom and S. H. 



Ayers. 



A series of experiments was devised to test the effects of temperatures 

 commonly used in pasteurization upon the spores of pure cultures of 

 a series of species of Penicillium, Aspergillus, Mucors, one form of Fus- 

 arium, and Oidium ladis. Results are summarized as follows: 



1. The holder process of pasteurization in which milk was heated 

 to 145°F. (62.8°C.), and maintained at that temperature for 30 minutes 

 killed the conidia of every species investigated, except those of Asper- 

 gillus repens, A. flavus, and A. fumigatus. The molds which survive 

 are only found occasionally in milk. 



2. The flash process of pasteurization, where milk was heated to 

 165°F. (73.9°C.), for a period of 30 seconds, destroyed the spores of 

 all the molds tested with the exception of many spores of one form and 

 occasional spores of three more forms. At 175°F. (79.5°C.), only 

 occasional spores of two forms developed. 



3. When the heating process was performed in dry air for a period 

 of 30 minutes at 200°F. (93.3°C.), 31 out of 42 forms of Penicillium and 

 7 out of 24 forms of Aspergillus were destroyed, but none of the cultures 

 of Mucors. A temperature of 250°F. (121. 1°C.) over a period of 30 

 minutes killed all the forms of Penicillium tried, but left an occasional 

 living spore in one species of Aspergillus and 3 out of 6 Mucors. 



The use of 0.01 Cubic Centimeter Pipettes in Bacterial Milk Analysis. 



James D. Brew. 



There are two common ways of measuring milk for counting bacteria 

 with a microscope; one, by loops and the other by capillary pipettes. 

 Prof. H. W. Conn, in his report on an investigation recently conducted 

 in New York City, concludes that the wire loop as used by one of the 

 laboratories making the counts appears to yield results as accurate as 

 those secured by using 0.01 cc. pipettes. This conclusion is based 

 upon comparative counts; but owing to possible wide variations in 



