1020 EXPERIMENT STATION EECORD. 



and that variability attacks only one characteristic at a time. The forms of heredi- 

 tary variability are grouped in 3 classes: In those in which variation is caused by 

 degeneration all the individuals gradually losing their vegetative power, so that species 

 may cease to exist. By transformation, individuals may lose a specific characteristic 

 and acquire another. By hereditary variability or variation, the normal form throws 

 off some individuals which possess characteristics strongly differing from those of 

 the normal form, while the normal form continues to propagate quite unchanged. 

 The author believes that many of the so-called new species are only variants of others 

 and are not new species. Especially is this true among bacteria where the want of 

 crossing strongly favors the continuation of variants once produced. If these variants 

 become isolated the discoverer is liable to recognize theni as new s^pecies, l)ut their 

 affinities can be determined only after prolonged investigation. 



Symbiosis and symbiotic ferm.entation, J. R. Greex ( Pror. Roy. Inst. Great 

 Britain, 16 {1900), TI, No. 94, pp. 261-273). — In a paper read before the Royal Insti- 

 tution, the author discusses symbiosis at considerable length, describing many of 

 the best known forms. Among those mentioned are the symbiosis between phan- 

 c ogams, the symbiosis of lichens, the symbiosis existing between the Leguminosaj 

 and the bacteria of the root tubercles, and the symbiosis in kephir, ginger beer, and 

 that reported from Madagascar in which sugar cane is attacked by organisms which 

 consist of yeast and bacteria associated in the same way as are the organisms of the 

 ginger-beer plant. 



The disinfectant properties of washing powders, C. F. Doane [Maryland Sla. 

 Bid. 7.9, pp. .11-64). — A report is given of the value of a number of washing powders, 

 sal soda, baking soda, and caustic soda as disinfectant agents for the cleansing and 

 purifying of culinary and dairy implements and vessels. The washing powders were 

 found to have a decided value for destroying Vjaeteria, as also did the sal soda. Bak- 

 ing soda had little or no effect on the germs present in the cultures tested. Dilute 

 caustic soda was also without effect. A test was made to determine whether the free 

 alkali in the washing powders is entirely responsible for their antiseptic proi)erties, 

 the results indicating that such is not the case. 



The effect of physical agents on bacterial life, A. M.\cfadyen {Proc. Roy. 

 Inst. Great Britain, 16 {1900), II, No. 94, pp. 448-457). — An abstract is presented of a 

 paper in which the effect of various physical agents on liacterial life is described. 

 Among those mentioned are gases, electricity, mechanical agitation, etc. 



Studies of the efficiency of water filters in removing different species of 

 bacteria, S. De :\1. Cm^k (Ma^^xarhiisctts Stat,; B,t. Health Rpt. 1900, pp 527-535).— 

 A report is made on the relative efficiency of continuous and intermittent filters for 

 the removal of bacteria from river M'ater. The filters were constructed, and the waters 

 tested were supplied with a number of species of organisms, and the filtrate exam- 

 ined. The intermittent filter showed somewhat greater distribution of species and a 

 slightly poorer efficiency than the continuous filter. The efficiency of the continuous 

 filter in removing bacteria in everj^ instance Init one was about 99 per cent. Both 

 kinds of filters were most efficient in the removal of the more common and widely 

 distributed species of bacteria. 



Notes are also given on the significance of Barillns coll in filtered water. This 

 organism is found in the effluents of filters more connnonly than B. tyjtJil, the waters 

 being examined for that organism at the sanie time. The exj)eriments indicate that 

 B. coli is more hardy than the other species, and B. typhi could not serve as a test 

 organism as well as the previous species. 



Studies of media for the quantitative estimation of bacteria in -water and 

 sewage, 8. De M. Gage and E. B. Phelps {Reprint from Pror. Ayner. Pitli. Health 

 Assoc. 1901, pp. 8). — A report is given of the comparative value t>f a number of 

 different media for the estimation of bacteria in waters and sewage. The tendency 

 at present is toward a medium which will permit of the shortening of the period of 



