131 



For ten years \ve have used the bruised leaves, sprinkled with 

 molasses water, as a fly-poison. It attracts swarms of the noisome 

 insects, and is sure death to them." 



Although the seeds of Gym?iocladiis are harmless, and have been 

 used as a substitute for coffee, the leaves of the tree are said to con- 

 tain cytisine, a vegetable principle which, in certain doses, acts on the 

 human subject as an acrid poison. It is perhaps to this principle 

 that are to be ascribed the effects of the leaves as an insecticide. 



Latent Vitality of Seeds. — Messrs. Ph. Van Tieghem and Gaston 

 Bonnier have been making some preliminary experiments, says The 

 Gardeners' Chroiiide^ to ascertain the effects of different conditions 

 on the latent vitality of seeds. On January 9th, 1880, several pack- 

 ets of seeds supplied by Vilmorin were divided each into three equal 

 parts/ One portion was exposed to the free air, but secured from 

 from dust ; another portion was put into closed air, securely 

 corked up in a tube ; while the third was placed in pure carbonic 

 acid. At the end of two years the seeds were taken out and w^eighed, 

 and afterwards sown. With regard to weight, all ihe seeds exposed 

 to free air showed an increase. Thus, for example, fifty seeds of the 

 common_pea were found to have increased about -^ oi their original 

 weight ; and fifty seeds of the French bean about ^ of their original 

 weight. The seeds confined in closed air increased in weight, but 

 infinitely less than those exposed to free air^ and the increase in some 

 instances was so trifling as to be hardly measurable. Thus, fifty 

 peas increased about y^ of their original weight, and fifty beans 

 about ytW ^f their original weight. As for the seeds placed in carbonic 

 acid, they did not vary half a milligramme from their original 

 weight. The following are two examples of the comparative germi- 

 nation of the seeds, the conditions being as near as possible exactly 



the same : 



Peas left in the free air, 90 per cent, germinated. 

 *^ " *' closed air, 45 per cent, germinated. 



carbonic acid, o per cent, germinated. 

 Beans " " free air, 98 per cent, germinated. 

 " " " closed air, 2 per cent, germinated- 



(< a u 

 u a 



it a u 



carbonic acid, o per cent, germinated. 



T/ie Cross-fertilization of Flowers by Insects. — In his translation 

 of Darwin's work on Cross-fertilization, M. Heckel, in a foot-note, 

 urges, as a decisive argument against the cross-fertilization of flowers 

 by insects, the fact that these latter auxiliary aids are absent from 

 the flowery summits of high mountains, or at least are extremely rare 



there. 



M.Ch.Musset,after four years' residence and observation at Grenoble, 

 in the centre of a region which has all altitudes from 600 to 10,000 feet, 

 comes forward with a note in the Comptes Rendus of the Academic 

 des Sciences (T. xcv., No. 6), in which he fully confirms the views of 

 Darwin, and shows that M. Heckel's objection must fall to the 

 ground. He testifies as the result of manifold observations of his 

 own, supported by the testimony of several distinguished botanists 

 and entomologists of the region, that all orders of insects are repre- 

 sented up to an altitude of 9,800 feet; that above that height Lepi- 



