888 EXPERIMENT STATION RECORD. I Vol. 41 



opinion being that tlie implement promises to give good results. Traction tests 

 showed that it required a greater tractive effort than the so-called vibrating 

 or spring-toothed cultivator, and that the latter implement gave somewhat 

 better results. It is thought that the disk harrow, while giving good results, 

 is not entirely adapted for use on very heavy compact soils. Its traction re- 

 quirements necessitate the use of two horses, which lowers its efBciency for 

 vineyard cultivation. 



Tests of mechanical cultivating apparatus, M. Feerouillat {Vie Agr. et 

 Rurale, 8 {1918), No. 40, PP- 251, 252). — In connection with tests of a single 

 10-h. p. tractor on loose sandy vineyard soil, traction tests on a 3-bottom plow 

 covering a width of about 30 in. and working at depths of from 5 to 6 in. 

 showed a total average traction of from 221 to 322 kg. (487 to 708 lbs.). 

 Tests of a double flexible toothed harrow covering a width of aboJt 5 ft. and 

 working at a depth of about 4 in. gave a total average traction of about 680 

 lbs. Other tests of special apparatus are noted. 



Becent advances in the differentiation of lactose-fermenting (gas-produc- 

 ing) bacilli, with special reference to the examination of water and food 

 products, D. R. Wood (Jour. Hyg. [Cambridge], 18 {1919), No. 1, pp. 46-58).— 

 Investigations are reported which confirm studies by American bacteriologists 

 and show that lactose-fermenting or gas-producing bacilli can be divided into 

 two main types, distinguishable by the methyl red and Vosges-Proskauer 

 reactions. 



The methyl red — Vosges-Proskauer-}- type were found to be rare in human and 

 animal feces, more common in surface water, milk, and sewage, and the pre- ■ 

 dominant type in soil and grain, and to be more resistant than the methyl red+ 

 Vosges-Proskauer — type. The methyl red type was found to predominate in four 

 out of six samples of soil. 



Organisms of the methyl red type were found in 66 samples of water out of 

 a total of 200 containing lactose fermenters, and in 41 samples containing this 

 type no evidence of recent contamination could be found. Twenty-nine of the 

 66 samples were from water sources of good repute, mostly public supplies. It 

 is concluded that judgment of the water was liable to modification by the 

 recognition of this organism. 



"The presence of lactose fermenters of the ' M. R.— ' 'V. P. 4-' type must be 

 regarded with considerably less disfavor than the presence of ' M. R.-f-' ' V. P. — ' 

 organisms, and the application of tests for the recognition of these types is im- 

 portant. It is suggested that these tests should be included in all routine ex- 

 aminations of water and food products." 



The deoxygenating effect of the effluent from the Miles acid process of 

 sewage treatment, F. W. Mohlman; {Engin. and Contract., 50 {1918), No. 7, 

 pp. 166, 167, fig. 1; also in Jour. Indus, and Engin. Cliem., 11 {1919), No. 4< PP- 

 325-327, fig. 1). — Experiments with the Miles acid process of sewage treatment 

 led to the conclusion that the acid effluent from this process contains unox- 

 idized sulphur dioxid which is oxidized at the expense of the dissolved oxygen 

 in the water in which the effluent is diluted. 



" The sulphur doxid may be oxidized before dilution by aeration for a short 

 time with relatively small quantities of air. After this aeration the effluent 

 will not de-aerate large volumes of diluting water." 



RURAL ECONOMICS. 



Some after-the-war problems in agriculture, G. F. Warren {Jour. Farm 

 Econ., 1 {1919), No. 1, pp. 12-23).— Problems of unemployment, police protec- 

 tion, education, labor, laud ownership, food distribution, cooperation, equality 



