AGRICULTURAL BOTANY. 131 



leaves, but small proportions were found in the fleshy or juicy portions in the 

 case of gourds, tomatoes, and beans when fresh, only traces being found in 

 dried grains, peas, etc. Absorption of arsenic by soil is said to vary with the 

 concentration and time and to be incomplete. 



Arsenic was recovered from the soil under olive trees that had been sprayed 

 therewith for olive fly. It is considered necessary to regulate the use of arsenic 

 in such connection on account of possible injury therefrom. 



Studies on the anatomical and physiolog-ical influence of tobacco smoke on 

 seedlings, A. Purkyt (Anz. K. Alcad. ^y^ss. [Vienna], Math. Naturw. Kl., 1912, 

 No. 17, p. 265; a&.s\ in Centhl. Bakt. [etc.], 2. Abt., 38 {WIS), No. 7-12, p. 211).— 

 The author reports that in tobacco smoke plants develop high turgor which is 

 later gradually lost; that abnormal thickening of the stems is due to growth 

 in the size but not in the number, of cells, which in case of the leaf epidermis 

 Is expressed in alterations of form, hypertrophy of stomata, and deformation 

 of leaf hairs; and that along with other changes mentioned, the formation of 

 both wood and bast fiber is limited by exposure to tobacco smoke. 



Injuries to vegetation by furnace gases and ashes, H. C. Muxleb et al. 

 {Ber. Agr. Chem. Kontroll u. Vers. Stat. Pflanzenkrank. Prov. Sachscn., 1912, 

 pp. 19-22). — A condensed and apparently preliminary account is given regarding 

 the probable or actual injury done to vegetation in the neighborhood of certain 

 furnaces, factories, etc., distributing smoke gases, ashes, and -dust. An illus- 

 trative table is given showing that leaves and twigs of hawthorn in an exposed 

 situation gave a considerable increase of the ash, chlorin, and sulphur content. 



Effects of illuminating gas on vegetation, G. E. Stone (Massachusetts Sta. 

 Rpt. 1912, pt. 1, pp. 45-60, pis. 2). — The author presents a general description 

 of the effects of gas poisoning on trees and gives a number of specific examples 

 of injurious as well as stimulating effects due to illuminating gas. The 

 symptoms of gas poisoning are said to be best obtained from a careful examina- 

 tion of the wood at the base of the tree or the roots. 



During the winter a break in a gas pipe led to the defoliation of a large num- 

 ber of plants in a short time. Those most severely injured were roses, ger- 

 aniums, and abutilou, though others were also somewhat injured. The ferns, 

 mosses, and liverworts near the gas inlet were scarcely affected. After being 

 defoliated the geraniums and abutilon produced small leaves, and the leaves 

 on the variegated abutilon which were put out were entirely green. 



On Carolina poplars illuminating gas is said to show some characteristic 

 effects. The symptoms of gas poisoning are generally a peculiar swelling and 

 cracking of the bark, the lesions often extending for a foot or more along the 

 trunk. On the sides of these cracks the bark was bulged out and examination 

 showed a thick layer of soft parenchymatous tissue extending to the wood and 

 apparently derived from the cambium zone. It is believed that the absorption 

 of the gas may have killed the tissue exterior to the cambium layer before the 

 cambium itself was affected, and that, in this way, the tension of the outer 

 tissues being diminished, a stimulation of the cambium cells resulted. 



When willow cuttings were grown in water charged with illuminating gas 

 from time to time, there was found to be a slight acceleration in the develop- 

 ment of all plants subjected to gas, although the gain was not very marked^ 

 The development of the lenticels and roots seemed to be considerably favored 

 where the cuttings were placed in the gas-charged water. 



Influence of a radio-active body on germination, J. Crochetelle (Jour. Agr. 

 Prat., n. ser., 26 (1913), No. 37, pp. 332, 333, fig. i).— The author gives a pre- 

 liminary report of his experiments regarding the influence of radio-active sub- 

 stance on some common plants. st<ating that while the results obtained with dif- 

 ferent plants were not uniform, bean seedlings so treated showed a striking 



