BOOKS AND CURRENT LITERATURE 23 



rainfall occurred in such small amounts. Whether a storm is suffi- 

 ciently heavy to be of benefit to plants must depend on several features 

 among which would be the season, the kind of soil, and the amount of 

 moisture in it at the time of the storm. Measurements which the 

 reviewer made of rain penetration at different stations in the Eyre 

 region showed, as a matter of fact, that it required a surprisingly smart 

 shower to effect any marked moisture penetration. It would be a 

 very interesting and useful thing if the various meterological offices 

 would make an investigation into what constitutes an effective fall of 

 rain and put out the same together with rainfall totals. 



Finally, it would have made the work of considerable more service, 

 it seems clear, had there been added a good index. Reference books 

 without indexes are badly handicapped. — W. A. Cannon. 



The Conditions of Fruitfulness. — In their bulletin on Vege- 

 tation and Reproduction with special Reference to the Tomato, Kraus 

 and Kraybill 1 have presented physiological and biochemical studies as 

 important evidence in the elucidation of the problem concerned with 

 the interrelations existing between fertilization, vegetative vigor and 

 seed and fruit development. It has been shown that at least some of 

 the instances of sterility considered to be the result of physiological 

 incompatibility may be due to the state or condition of nutrition of 

 the plant itself. Furthermore, both environmental and hereditary 

 factors must be considered in any attempted explanation of the repro- 

 ductive and vegetative behavior of plants. The results of the experi- 

 ments tend to support the theory they present, namely that vegetative 

 vigor and reproductive vigor are dependent upon a definite relationship 

 between the carbohydrate and nitrogenous compounds in the plant. 

 Some of the important conclusions follow: 



Plants grown with an abundant supply of available nitrogen and 

 the opportunity for carbohydrate synthesis are vigorously vegetative 

 and unfruitful. Plants grown with an abundant supply of nitrogen 

 and then transferred and grown with a moderate supply of available 

 nitrogen are less vegetative but fruitful. Plants grown with an 

 abundant supply of nitrogen and then grown with a low supply of 

 nitrogen are very weakly vegetative and unfruitful. Fruitfulness is 

 associated neither with highest nitrates nor highest carbohydrates, but 

 with a condition of balance between them. 



1 Kraus, E. J. and H. R. Kraybill. Vegetation and reproduction with special 

 reference to the tomato. Bui. 149, Oregon Agr. Col. Exp. Sta. 1918. 



