ENTOMOLOGY. 507 



the blood.' 1 Some lines of experiments with insecticides based on the 

 presence of potassium phosphate in the digestive fluids of the gypsy 

 moth larvae are suggested. 



Arsenate of lead: Its manufacture and chemical composition, 

 F. J. Smith (Agr. Massachusetts, 1897, pp. 357-369).— Arsenate of lead 

 suitable for spraying is prepared from commercial grades of arsenate 

 of soda and either acetate of lead or nitrate of lead. The proportions 

 and properties of these ingredients are described. The lead oxid con- 

 tent was found to vary from 58.81 per cent to 66.795 per cent in 8 

 samples of acetate of lead, and from (56.37 per cent to 68.37 per cent in 

 3 samples of nitrate of lead. Four samples of arsenate of soda showed 

 a variation of 36.77 per cent to 47.8 per cent in arsenic pentoxid. It 

 also varied in percentages of chlorin and other foreign substances. 

 The chemical composition and properties of arsenate of lead and the 

 chemical actions involved in the preparation are given in detail. For- 

 mulas are given for computing the quantities of acetate of lead and 

 arsenate of soda required to prepare a given quantity of arsenate of 

 lead. 



Danger from the use of arsenate of lead, A. H. Kirkland {Agr. 

 Massachusetts, 1897, pp. 390-393). — Analyses were made of the urine of 

 men engaged in extensive spraying operations against the gypsy moth. 



"The results of these analyses show conclusively that in some cases men engaged 

 in spraying acquire dangerous amounts of arsenic. That actual sickness resulting 

 from this work is rare is shown hy the fact that but few of our many employees 

 lost time frum this cause. ... It may be stated, in general terms, that while an 

 occasional person may become poisoned during extensive spraying operations with 

 arsenate of lead, premonitory symptoms appear in ample time lor a change of work 

 to be arranged; and since the conditions existing in the work against the gypsy 

 moth are exceptional, the farmer or fruit grower may use this insecticide witli less 

 fear of danger from poisoning than is the case where Paris green or London purple 

 is used. Iu all cases proper care must be taken in handling the poison and in pre- 

 venting the exposure of the skin to the spray." 



Concerning the direct combating of phylloxera on stock, C. 

 Mohr (Ztschr. J'Jianteuhraul:, 8 (1898), No. 2, pp. 69, 70). — The author 

 recommends the use of 0.5 liter benzolin in 100 liters of water, to be 

 made neutral to litmus paper with sulphuric acid. This mixture is to 

 be poured about the roots of the infected plants, 10 to 15 liters being 

 used for each plant. It is further stated that this solution can be used 

 with benefit for destroying various forms of plant lice on many other 

 plants. 



Experiments -with insecticides, A. H. Kirkland and A. F. 

 B jug-ess {Agr. Massachusetts, 1897, pp. 370-389). — Both indoor and out- 

 door tests of the relative value of various insecticides iu killing gypsy 

 moth larvae are reported. The data obtained are reported in tabular 

 form. Some of the conclusions are as follows: 



"While arsenic seems slightly superior to Paris green so far as killing effects are 

 concerned, its high specific gravity renders it difficult of suspension in water, and 

 hence it can not be applied evenly to the foliage. . . . Experiments with chemically 



