256 ROSACEA. 



grown in Holland under precisely similar circumstances, in each month 

 of the year. The results proved that the product obtained during the 

 winter and early spring was weaker in the acid in the proportion of 

 17 to 24, 28, or 30, the strongest water being that distilled in July and 

 August. This chemist found that a stronger product was got when 

 the leaves were chopped fine, than when they were used whole. 

 According to Christison,^ the buds and very young leaves yield ten 

 times as much, essential oil as the leaves one year old. We have 

 ascertained that leaves collected in January when they were thoroughly 

 frozen yielded a distillate containing about ten times less of hydrocyanic 

 acid than in summer. The product obtained from the leaves collected 

 in January, but previously dried for several days at 100° C (212° F.), 

 still proved to contain both essential oil and hydrocyanic acid. 



The unwounded leaves of the cherry-laurel in vigorous vegetation 

 have been shown by our friend Prof. Schaer, not to evolve naturally a 

 trace of hydrocyanic acid, though they yield it on the slightest 

 puncture. We are ignorant of the mode of distribution in the living 

 tissue of the lauro-cerasin, and of the substances causing its decompo- 

 sition, and how these two bodies are packed so as to prevent the slightest 

 mutual reaction. The leaves may be even dried at 100° C. and 

 powdered without the evolution of any odour of hydrocyanic acid, but 

 the latter is at once developed by the addition of a little water ; on dis- 

 tilling its presence is proved by means of all the usual tests in the first 

 drops of the product. 



Besides the substances concerned in the production of the essential 

 oil, the leaves contain sugar which reduces cupric oxide in the cold, a 

 small quantity of an iron-greening tannin, and a fatty or waxy 

 substance. 



Schoonbroodt (1868) treated the aqueous extract of the fresh leaves 

 with alcoholic ether, which yielded ^ per mille of bitter, acicular 

 crystals ; these quickly reduced cupric oxide, losing their bitterness. 



Bougarel (1877) isolated from the leaves under notice and several 

 others, Phyllinic acid, a crystalline powder melting at 170° C. 



Uses — The leaves are only employed for making cherry-laurel 

 water {Aqua Lauro-cerasi), the use of which in England is generally 

 superseded by that of the more definite hydrocyanic acid, 



FLORES KOSO. 



Flores BrayercB, Cusso, Kousso, Kosso. 



Botanical Origin — Hagenia abyssinica Willd. (Brayera anthel- 

 niinthica Kunth), a handsome tree growing to a height of 60 feet, 

 found throughout the entire table-land of Abyssinia at an elevation of 

 3,000 to 8,000 feet above the sea-level.^ We have never noticed it 

 growing in any botanic garden. The tree ^ is remarkable for its abun- 

 dant foliage and fine panicles of flowers, and is generally planted 

 about the Abyssinian villages. 



^ Dispensatory, 1842. 592. from Madagascar to the Paris Exhibition 



2 The French section of the International of 1878. 

 African Association contributed Kousso ^ Fig. in Bentley and Trimen, " Med. 



Plants, part 5 (1876). 



