ioo Green. — On Vegetable Ferments. 
of the embryo, and that amygdalin was only present in the 
cotyledons. In 1877 Pfeffer 1 gave as his opinion that both 
ferment and glucoside were present together in the cells, the 
former being in the protoplasm, the latter in the cell-sap. In 
1887 Johansen 2 found that emulsin exists in both varieties 
of the almond, and is distributed in the fibro-vascular bundles 
and the cells abutting on them,, particularly in those of the 
cotyledons. He found amygdalin in the parenchyma of the 
cotyledons of the bitter variety only. In 1890 Guignard 3 
published the results of a very careful research into the distri- 
bution of the ferment in both the almond and the cherry 
laurel. His work was partly based on micro-chemical 
methods, while he confirmed his results by observing what 
parts of the tissues had, when isolated, the power of liberating 
HCN from a solution of amygdalin. In his work he quotes 
two micro-chemical reactions on which he found himself able 
to rely. One of these is the development of a violet colour in 
cells containing emulsin when a section is treated with a 
solution of orcin in hydrochloric acid. The second is the 
behaviour of the same cells with Millon’s reagent. Instead of 
the pale brick-red or rose-red which proteids give with this 
fluid, emulsin gives a much deeper and more persistent 
orange-red colouration. Certain layers of tissue which gave 
these colour-reactions were found, when very carefully isolated 
by dissection, to be capable of liberating HCN from a weak 
solution of amygdalin, and yielding at the same time the 
characteristic odour of benzoic aldehyde. 
Guignard found the distribution of the enzyme in both the 
cherry-laurel and the almond to be in the neighbourhood of 
the fibro-vascular bundles, but not in quite the same layer in 
the two cases. In the case of the first named plant he pre- 
pared it from leaves and twigs, and located it chiefly in the 
endodermis. In the almond he only detected it in the seed 
and young seedling, where it was chiefly in the pericycle of the 
1 Pflanzen-Phys., t. I, p. 307, 1881. 
2 Ann. des Sc. Nat. Bot. ser. 7. t. VI, p. 118, 1887. 
3 Journal de Botanique, 1890, p. 3, et seq. 
