Revieiv 219 



Cultivation carries with it a great quantitative and qualitative modi- 

 fication of the fauna of plants. A chapter is given on the relations 

 between the parasites of insects and their hosts. 



Professor P. Marchal gives an account of arsenical sprays and the 

 treatment of fruit trees in America and France, pp. 242-280. 



A section is devoted to the relation of arsenical sprays to the con- 

 sumer of fruit. The results of experiments quoted, show that owing to 

 rain and atmospheric conditions generally, the danger is negUgible. 

 Obvious precaution is necessary after spraying with regard to cattle 

 and herbs which grow in orchards. Observations and recommendations 

 based on experiments carried out in 1917 are given and an extensive 

 bibhography is appended. 



Among the mycological papers Professor E. Foex, Director of the 

 Vegetable Pathology Station in Paris, gives detailed observations of 

 Leptosphaeria herpotrichoides, the causative organism of a disease of 

 wheat, pp. 200-213. The practical apj)hcation of the results of the 

 investigations are summarized. 



Professor L. Ravaz, Professor at the National School of Agriculture, 

 Montpellier, in an account of experimental research on the treatment 

 of vine mildew, pp. 281-288, gives much useful information of practical 

 value, especially with regard to the effect of spraying formulae on the 

 plant and on the fungus. 



G. Arnaud has given notes and descriptions of some new or httle 

 known diseases in France. The author notes the development of 

 Rhizoctonia solani on potatoes, due to the favourable dry season, while 

 on the other hand Phytopthora has been greatly restricted. 



An interesting article on the destructive action of fumes from the 

 Chedde factory in Savoy is written by Professor L. Mangin, pp. 187-199. 

 The author shows that Hydrochloric acid, which are the harmful fumes, 

 exerts the greatest effect during foggy weather, and least during dry 

 periods. 



Several other mycological and entomological articles complete this 

 most interesting and valuable volume. 



J.D. 



