BOOK REVIEWS. 



593 



cultivation and for trees on lower stems, such as are called bushes in 

 England. An alternative to the use of grass is the planting of cover 

 crops. They are recommended for several reasons, amongst which 

 the following are the most important. On sloping lands they serve 

 to hold the water, preventing the soil from being washed away. They 

 check the autumn growth by Hmiting the water supply, and finally 

 add a considerable amount of humus to the soil. When such cover 

 crops are of leguminous plants a certain proportion of nitrogen is, of 

 course, added as well. The plants most generally used for this purpose 

 are various Clovers, Vetches, Rape, Barley, Rye, and Soy Beans. 



The usual pests, both insect and fungus, are figured and described, 

 but we do not note any new methods of treatment. It is unfortunate 

 that the Latin names of these are not given, as, though a " railroad 

 worm " may be recognized at once on the other side of the Atlantic 

 its identity here is by no means certain. 



It is useful to note that experiments have been tried as to the 

 danger to cattle of the arsenical spray which falls on grass when the 

 trees are being sprayed in spring. Such grass was cut and given to 

 horses, and cattle were also grazed under the trees, with no harmful 

 effect. Furthermore, the small amount of arsenic which sometimes 

 remains in the calyx of apples has been proved to be so insignificant 

 that eight or ten barrels of fruit might be eaten v/ithout any ill effect. 



It is also interesting to learn that in the Western States thinning 

 of the fruit on the trees is practised and is considered commercially 

 successful, and the author strongly advocates its adoption in the 

 Eastern sections, with which his book is particularly concerned. 



Upon the oft-debated question of gathering in bags or baskets, the 

 author still believes in a padded basket, and the new apparatus, which 

 resembles a cross between a pail and a sack, he does not consider 

 advisable save in extremely careful hands. 



The question of storage is dealt with rather fully, and its value as 

 enabling the grower to hold his fruit should prices be unfavourable 

 is very strongly emphasized. The importance of a certain amount 

 of moisture is very strongly advocated for the successful keeping of 

 fruit, and it is stated that one of the most successful stores has a stream 

 of water always running through it. 



The whole work is written in the cheery tone which one expects 

 from America, and it is well printed and illustrated. Unfortunately, 

 these illustrations have necessitated the adoption of a heavy clay- 

 laden paper, and the book is therefore somewhat unpleasantly heavy 

 to hold in the hand. 



" Transpiration and the Ascent of Sap in Plants." By H. H. Dixon, 

 Sc.D., F.R.S. 8vo. 216 pp. (Macmillan, London, 1914.) 5s. net. 



This work contains eleven chapters. The first deals with The 

 Nature oj Transpiration, but it is remarkable that the author entirely 

 omits to say anything about the cause of it. All botanists are aware 

 that it is light, and not heat, which is the agent ; and, as Henslow has 



