1»16J AGRICULTURAL BOTAKY. 133 



ordinary season and were much more robust than usual. A specimen of 

 Chelone glabra grew luxuriantly and flowered freely, though for some years 

 it had barely kept alive. On the other hand, the rather xerophytic Sedum 

 telephioides and Hedera helix showed no better growth than usual, and some 

 other plants, as Saponaria officinalis and Oxalis corniculata, showed little in- 

 crease over their usual size. It is thought that the differences noted were due 

 to increased water supply, and that many plants of agricultural importance 

 may be as sensitive to the effects of diminished water supply as the Aster, 

 Asclepias, and Helianthus previously mentioned. 



Radium and plant growth {Gard. Chron., 3. ser., 58 (1915), No. 1501, p. 

 209). — In comments on the results of a number of experiments said to have 

 been carried out by M. H. F. Sutton, it is stated that in no case was it apparent 

 that any of the radium preparations had a beneficial effect on the growth of 

 the crops. In not a few instances there were deiinite indications that the prepa- 

 rations had exercised an adverse influence on the plants. 



Bibliography on the effect of sulphur dioxid on vegetation and animal life 

 (U. S. Dept. Int., Bur. Manes Bui. 98 (1915), pp. 503-520) .—This bibliography, 

 which is said to have been prepared by the chemists' club library of the Selby 

 Smelter Commission, lists nearly 100 articles upon the biological effects of 

 sulphur dioxid, giving notes or brief abstracts of most of the articles mentioned. 



Disappearance of sulphur dioxid from dilute mixtures of sulphur dioxid 

 with air, G. C. Baktells, Je. (U. S. Dept. Int., Bur. Mines Bui. 98 (1915), pp. 

 308-323, pis. 2). — These investigations were carried on to test certain observa- 

 tions made in the field fumigation experiments previously noted (E. S. R., 35, 

 p. 28). 



It is stated that the disappearance of sulphur dioxid from a mixture thereof 

 with air, when introduced into a carboy containing green vegetation, was 

 found to be due in great part to absorption of sulphur dioxid by the plant, but 

 in some degree also to the oxidation of the sulphur dioxid in an excess of 

 moist air and to absorption by the surface of the glass. Experimentation 

 showed also that when a mixture of sulphur dioxid and dry air was left in a 

 glass container, there was a disappearance of the sulphur dioxid to the extent 

 of about 10 per cent in 30 hours. The disappearance was greater when the air 

 showed a relative humidity of 50 per cent than it was in dry air, and much 

 greater at a humidity of 100 per cent. When a mixture of sulphur dioxid 

 and air was exposed to the action of direct sunlight, a gradual disappearance 

 of the sulphur dioxid took place. This was greatest when the temperature was 

 highest, which fact is considered to preclude the view of its solution by water. 

 In all cases both oxidation and absorption took place to an extent which was 

 greater in a moist than in a dry atmosphere. 



Defects in the investigation of smoke injury, S. Eickk (Ztschr. rflanzen- 

 krank., 25 (1915), No. 1, pp. 45-59). — Discussing the methods, results, and pres- 

 ent state of study of the relations between soil, plant, and smoke, also between 

 smoke and the aerial portions of plants, the author calls attention to some of 

 the gaps in our present knowledge in this connection. 



Tests of various brands of litmus for bacteriological work, Christie J. 

 Mason (Connecticut Storrs Sta. Bui. S3 (1915), pp. 126. 127).— The autlior 

 gives a report on an investigation of different brands of litmus to determine 

 their adaptability for bacteriological purposes, basing her conclusions on the 

 numbers of bacteria which developed In lltmus-lactose-gelatin plates prepared 

 for testing milk or Its products. Of the four brands of litmus tested, litmus 

 cubes were found to be the most satisfactory though the difference between 

 azolltmin and litmus cubes was slight. The other forms of purified litmus are 

 said to have inhibited the growth of bacteria to a noticeable degree. 



