ABSTRACTS. 



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the meadow it killed out all other plants, forming a dense deep patch of 

 spiny creeping stems with pink blossoms. — G. H. 



Silage Studies. By Fred. W. Morse (U.S.A. Agr. Exp. Stn. New 

 Hampshire, Bull. 92, Sept. 1902, illustrated). — This bulletin deals with 

 various considerations in the treatment of silage which have arisen during 

 the last ten years of investigation. 



Amongst these are : 



1. The composition of the crop at different stages of growth- 

 Results show that the best silage is obtained from corn that has nearly 

 reached maturity. It then contains most dry matter and essential 

 nutriments, protein and soluble carbohydrates. Varieties should be 

 chosen yielding a mature crop at cutting time, rather than a larger but 

 immature plant. 



2. Comparison of varieties of corn for silage was based on the relative 

 merits of the ' Sanford ' flint, the ' Learning ' dent, and ' Mosby's 

 Prolific ' corn, which are placed in order of precedence. 



3. The amount of seed sown per acre affects the yield of green fodder 

 and also its composition. A medium stand (one bushel to the acre) gave 

 the best results. 



4. Changes in the composition of corn fodder while in the silo. This 

 is chiefly confined to the destruction of the soluble carbohydrates in the 

 plant, notably sugar, whereas starch is little affected, rendering important 

 the exact period at which to cut the corn for the silo, for as the ear ripens 

 the sugar changes to starch in the kernels and decreases in the stalk and 

 leaves. — C. H. C. 



Slug's and Snails. By W. C. Worsdell (Gard. Ghron. No. 829, 

 p. 349, Nov. 15, 1902, and No. 831, p. 390, Nov. 29, 1902).— Some 

 observations and experiments made by Prof. Stahl have thrown quite 

 a new light upon the relationship between these creatures and plants. 

 In this article Mr. Worsdell gives, as he says, " a general account, taken 

 from his [Prof. Stahl' s] book ' Pflanzen und Schnecken,' of the different 

 ways in which various plants are protected from slugs and snails." " Cer- 

 tain chemical substances are contained in the soft tissues of many plants, 

 which, although other parallel functions are not denied them, appear 

 to chiefly serve the purpose of warding off the attacks of snails ' ' (in this 

 term slugs are included). Of these tannin plays a very important part : 

 " those plants which contain this substance in considerable quantity are 

 seldom molested. Some plants possess an acid sap, caused by the presence 

 of binoxalate of potash, which is very distasteful to these molluscs ; other 

 plants have acid-secreting hairs, or their leaves contain ethereal oils 

 or bitter substances, which are also disliked. There are also various 

 mechanical means by which plants are protected, such as bristle hairs, 

 calcification of the cell membranes, the silicification of cell membranes, 

 mucilage, gelatinous structures, raphides, or isolated sharp-pointed 

 crystals of oxalate of lime. Experiments were made in many cases, by 

 depriving the leaves of the supposed noxious substances or qualities, to 

 see if the snails would then eat them, and in most cases it was found 

 that they would."— G. S. S. 



