FIELD CROPS. 325 



tho name amygdalaso is given. They state that the hydrolysis of auiygdalin 

 is due to a hitherto unrecognized constant of yeast which is the active agent in 

 sfi)arating tlie glucose. This euzym was separated by a system of extraction 

 at different teniiieratures. and its characteristics are described at length. It 

 appears to be eiiually well extracted from dried yeast at temperatures from 15 

 to 4.")° C".,'and while a small quantity can be obtained at zero temperature, the 

 amount may I)e greatly increased by heating for a short time to 45°. 



The action of naphthalin on plants, K. Aso {Bill. Coh Agr., Tokyo Imp. 

 I'liir.. 7 (1007), Xo. 3, pp. ^IS-Jfll, pi. 1). — On account of the recommendation 

 that naphthalin might be used to prevent attacks of nematodes, bacteria, etc., 

 the author carried on .some experiments to test the influence of naphthalin in 

 cultures containing barley, peas, buckwheat, millet, and rice. 



It was found that naphthalin could prevent the development of various soil 

 bacteria, although it did not kill them. In the proportion of 0.005 to 0.01 per 

 cent added to the soil naphthalin caused a moderate stimulation with barley, 

 buckwheat, and millet, but not with peas and rice. An increase to 0.05 per cent 

 injured the growth of all the plants. The injurious action is attributed to the 

 vapors of the naphthalin spreading through the soil, and since it injures plants it 

 can not be recommended as a remedy against nematodes, at least not in greater 

 iiuantities than 0.005 per cent of the soil. 



The accumulation of arsenic in the fruit of certain plants, B. Gosio {Atti 

 R. Accail. Lined. Hciiil. CI. »S'c/. Fis.. Mat. e Xat., 5. scr., 15 (1906), I, pp. 130- 

 131; (lbs. in Ceiithl. Bakt. [etc.], 2. Abt., 18 (1901), No. 22-23, pp. 72.}, 725).— 

 The author grew in boxes two squash plants, which, after they had attained a 

 length of 1 meter, were regularly watered with arsenic water of a strength of 

 1 part metallic arsenic to 1,000,000 of water After one month the strength of 

 the arsenic water was increased to 1 part in 100,000 and a month later to 1 

 icirt in 10,000. This was used to water the i)lauts until their growth was 

 lompleted. 



Leaves, stems, flowers, and fruits were analyzed for arsenic, and it was 

 Cound most abundant in the fruits, where it was present as metallic arsenic to 

 the extent of 0.0041 per cent. By gradually accustoming the roots to the effect 

 of arsenic the author believes even greater amounts would probably be 

 stored ui). 



Causes of injury to vegetation near a large industrial establishment, P. 

 Fr.vzer (Bi-Mo. Bui. Amer. Inst. MUi. Eiigin., 1901, No. 15, pp. 311-434, flgs. 2) .— 

 By means of experiments with saturated cloths, analyses of plants, and the 

 quantitative determination of sulphur in the air, the author has proved that the 

 injury to vegetation was due to the gases given off by a large establishment. 

 Studies were also made of the soot and dust driven (_)ut from smokestacks and 

 their effect on plant growth. A bibliography, with synopses of conclusions, 

 of a number of important contributions to the literature of this subject is 

 given. 



FIELD CROPS. 



The importance of nitrogen in the growth of plants, T. F. Hunt (Neir 

 York Cornell ,st(i. Bill. 2'/7, pj). 119-203, fiij.'i. 3). — The thesis of this bulletin is 

 that the amount of water soluble nitrogen occurring in the soil at a critical 

 time in the plant's life history may be a limiting factor in the growth of the 

 i-nip. With reference to this point the importance of nitrogen in the growth of 

 I>lants, th(( difference between nitrogen and other elements, the firaction of 

 nitr<)gen, the relation of total and water-soluble nitrogen, the purpose of cultural 

 methods, the conservation of moisture, and the results of dift'eernt experiments 

 considered as bearing on this subject are discussed. The discussion on the 



