261) Chronicles of Science. [^pril, 



Ohlique Leaves. — In a late volume of the Boston Society of 

 Natural History, Dr. Wilder shows that in the Elm the larger 

 portion is in the upper or most elevated side ; the leaves not lying 

 with their edges horizontally. In the Hornheam the outer or lower 

 portion is the largest. De Candolle and Herbert Sj)encer have 

 both tried to account for oblit^uity in leaves, but Dr. \Yilder con- 

 siders their reasoning to be insufficient. Dr. W. beheves it to be 

 caused by no external agency, but by an inherent constitutional 

 force. The German botanists, especially Schimper and Brauu, have 

 long since investigated the development of leaves in coimection witli 

 the general subject of phyllotaxis. They found that each leaf was 

 primarily a swelling or wave of growth freeing itself from the axis 

 of the embryo ; and that differences in size between the sides of a 

 leaf were caused by the greater force of the wave in its upward or 

 downward movement. Such pecuharities as have been pointed out 

 between the leaves of the Elm and the Hop Hornbeam exist therefore 

 in the earliest formation of the leaf, while yet connected with the 

 axis by a broad base, and before any constriction for the petiole has 

 taken place. Professor Agassiz considers the W'Ord " antistrophe " 

 as better expressing the inverse relation of correspondmg parts on 

 the opposite sides of a line than "symmetry." Dr. AVUder has 

 shown that the corresponding leaves on each side of a shoot are 

 symmetrical. 



The B'uhi, of Plymouth. — The Eev. A. Bloxham names a new 

 Kubus after Mr. Briggs, who has recently given a very interesting 

 account of the stations of the Eubi in his own neighbourhood. The 

 marvellously protean genus Buhus is one of the most uiteresting 

 studies at the present time for English botanists. By careful 

 examination we may hope to see definite relations of cause and 

 effect pointed out between the various species and their stations. 



The Culture of Opium. — Mr. Heffler, of Smyrna, describes 

 some of the difficulties and risks attending the cultivation of the 

 poppy in Asia Minor. The agricultural implements used are most 

 primitive, and no irrigation is applied. The poppy must be grown 

 in a moist but not a too wet soil, and hence is very much sub- 

 ject to injury from variations of season. Accordingly it is sown 

 at thiee different periods of the season, so that if one crop should 

 fail, another may have a chance of success. This method also 

 enables the labourers to gather first one field and then another, 

 which is desirable from the scarcity of hands and the necessity of 

 gathering just at the right time in the plant's development. When 

 the seed capsule is considered to have arrived at maturity, the 

 gatherers go into the fields and in a very skilful manner make 

 horizontal and vertical incisions in the outer portion of the capsule, 

 l)eing very careful not to penetrate to the seeds. On the morning 

 following this operation, the cuts are found to be covered with 



