296 PATHOLOGY [BoT. Absts., Vol. VII, 



ently the period of greatest foliage susceptibility of the host. The relations of temperature 

 and precipitation to frog-eye infection are discussed in some detail. — Of the protective ma- 

 terials used, Bordeaux mixture, lime-sulphur, and "Pyrox" proved the most effective in the 

 order named. Bordeaux mixture reduced the infection in per cent to 19.8; lime-sulphur to 

 21.5; "Pyrox" to 28.5; "Sulfocide" to 65.8; while sulphur dust gave no control. The average 

 infection on all the checks was 79.4 per cent. For the optimum control the fungicide should 

 be applied (1) just before the blossom buds open, (2) when three-fourths of the petals have 

 fallen, (3) two weeks later, (4) about the middle of June. The last application is not 

 necessary for commercial protection. Pruning and the destruction of dead twigs and limbs are 

 regarded as important accessories to spraying. — C. R. Orion. 



MISCELLANEOUS (COGNATE RESEARCHES, TECHNIQUE) 



2062. Anonymous. Proceedings of the twelfth annual meeting of the American Associa- 

 tion for Cancer Research. Absts. Bact. 4: 221-223. 1920. — Contains abstracts of the papers 

 presented. — D. Reddick. 



2063. Chapman, G. H. "Crack-neck:" A non-parasitic disease of chrysanthemums. 

 Phytopath. 9: 532-534. 1 pi. 1919. — A description is given of a non-parasitic malady occur- 

 ring in fancy forced chrysanthemums, with suggested control measures. — J. G. Dickson. 



2064. Davis, D. M., and E. O. Swartz. The testing of germicidal substances against the 

 gonococcus. Jour. Infect. Diseases 27: 591-601. 1920. — A new method for making germicidal 

 tests with the gonococcus is presented. It consists in mixing in sterile centrifuge tubes 1 cc. 

 of the gonococcus emulsion with 1 cc. of the properly diluted drug to be tested, incubating 

 for 20 minutes in a water bath at 37.5°C., centrifuging, washing with 0.85 per cent NaCl solu- 

 tion, centrifuging again, and finally inoculating liberally, and with a special loop, the washed 

 gonococci upon the surface of ascitic — or hydrocele — fluid agar. If the tubes show no growth 

 at the end of 7 days they are reinoculated with a fresh, viable culture of gonococcus, to prove 

 whether or not enough of the test drug was carried over with the transfer to make the medium 

 unsuitable for growth. — Selman A. Waksman. 



2065. Davis, Lewis. Some important factors in the preparation of culture media. Amer. 

 Jour. Public Health 10: 250-254. 1920. — The preparation of culture media is discussed with 

 special reference to the needs of the commoner pathogenic organisms. The importance 

 of peptone is stressed. Its value is dependent on the amount of amino acids and other 

 compounds present in a form utilizable by bacteria. A peptone hydrolyzed to a much greater 

 degree than the one formerly imported has increased nutritive values. Beef infusion is 

 superior to beef extract for the cultivation of pathogenic bacteria, and especially for the 

 production of toxins. The presence of a small quantity of fat in the infusion, however, has a 

 deleterious action, due, probably, to a depression in the surface tension of the medium. 

 Hydrogen-ion concentration is discussed and a general procedure for adjusting it by the colori- 

 metric method is outlined. The steam pressure method of sterilization is favored, but media 

 having a supernatant layer of oil for production of anaerobiosis are perfectly sterilized by the 

 intermittent method. — C. A. Ludwig. 



2066. Hartley, Carl, Roy G. Pierce, and Glenn G. Hahn. Moulding of snow-smoth- 

 ered nursery stock. Phytopath. 9: 521-531. 1919. — The authors describe a mulch injury or 

 snow mould of evergreen nursery stock, the disease also occurring to a less extent on young 

 trees in the forest. The disease can be distinguished by the fact that following the snow or 

 mulch injury, the roots remain healthy for a considerable time. Control measures are sug- 

 gested. — /. G. Dickson. 



2067. Jones, L. R., and M. Miller. Frost necrosis of tulip leaves. Phytopath. 9: 

 475-476. 1 fig. 1919. 



