BOTANY. 327 



them as required in his granaries. Care must be taken to renew the 

 tar from time to time in the course of the year, to prevent the return 

 of the insects." 



MODE OF PRESERVING PLANTS AND FLOWERS. 



A COMMITTEE appointed by the French Academy to examine a com- 

 munication of M. Gannal concerning "the preparation of plants for 

 herbariums, so as to preserve almost without change the color of the 

 flowers and leaves," made their report on Dec. 24, 1849. After re- 

 ferring to the present imperfect mode of preserving flowers, they ob- 

 serve that the essential condition in preparing plants is to dry them 

 as rapidly as possible, for if life remains in them for a few days the 

 color is lost, and other changes take place. An apparatus invented 

 by M. Gannal, which receives the approbation of the committee, dries 

 the most difficult plants in twenty-four hours. This process consists 

 in placing the plants in the leaves of gray paper, which absorb imme- 

 diately the moisture arising from rain or dew, so that they remain un- 

 changed for twenty-four hours. The next day they are placed in very 

 dry paper, after which they are put into the apparatus we are about to 

 describe, by which they are completely dried in twenty-four hours. 

 The principle of M. Gannal's method is, that the moisture under ordi- 

 nary circumstances evaporates very slowly, but by increasing the tem- 

 perature and lessening the atmospheric pressure it disappears much 

 more rapidly. To effect this he takes a cylindrical copper vessel, large 

 enough to contain readily a parcel of one hundred specimens, which 

 he places in it, and into the empty space at the sides puts about four 

 kilogrammes of quicklime, after which the cover is fastened. Having 

 been placed in a little basin, the apparatus is brought to a temperature 

 of 50 or 60 (Centigrade?) by means of boiling water turned into the 

 basin, after which a vacuum is created by a pneumatic pump fastened 

 to a cock in the cover. After creating the vacuum by pumping at in- 

 tervals for two or three hours, the plants are allowed to remain from 

 twenty-four to thirty hours, and are then perfectly preserved, with all 

 their natural colors and appearances. 



CHINESE BOTANICAL MEDICINE. 



M. DE PARAVEY drew attention to a substance well known in Chi- 

 nese medicine, which is called ou-poey-tsc. It appears to be a sort of 

 gall, possessing a very remarkable astringent power. It develops it- 

 self as an excrescence upon a variety of ash, and is used by the Chi- 

 nese with great success in cases of diarrhoea. Comptes Rendus, 

 Feb. 4. 



