Almonds were known during antiquity. They are mentioned several times in the Old Testament,2) also by Egyptian and by later Greek and Roman authors. Of the latter Theophrastus,3) Dioscorides,4) Scribonius Largus,5) Pliny,6) Palladius,7) Celsus,8) Alexander Trallianus,9) Platearius10) and others distinguished the bitter almond from the sweet. During the middle ages, both kinds of almonds were in use.

1) See p. 38.

2) Genesis, 43:11. - Numbers, 17:8. - Ecclesiastes, 12:5. - Rosen-muller, Handbuch der biblischen Altertumskunde. Leipzig 1831. Vol. 4, p. 263.

3) Theophrasti Historia plantarum. Lib. I, cap. 11, 18.

4) Dioscoridis De materia medica libri quinque. Editio Kuhn-Sprengel. Vol. 1, p. 155.

5) Scribonii Largi Compositiones medicamentorum. Editio Helmreich. 1887. p. 8.

6) Plinii Naturalis historiae libri. Lib. XVI, cap. 22; lib. XXXIII, cap. 75. - Editio Littre. Vol. 2, p. 127.

7) Palladii De re rustica, in Nisards Les agronomes latins. Paris 1877. p. 552.

8) Celsi De medicina libri VIII. Editio Vedrenes. Traite de m6decine. de A. C. Celse. Paris 1876. p. 274.

9) Alexandri Tralliani Medici libri XII. Editio Puschmann. Wien 1878. Vol.2, p. 445.

10) Platearii Liber de simplice medicina. "Circa instans." Editio Choulant.

Bitter almond oil is first mentioned in the writings of Sala-din1) in 1488 and those of Sancto Amando2) in the 16. century. The distillates from bitter almonds and of other Prunoideee, seem to have received but little attention during the period of general use of distilled waters. It is also uncertain whether the poisonous character of bitter almond oil was generally known. Even Scheele,3) when he discovered hydrocyanic acid in 1782 does not seem to have fully realized its poisonous properties. He did not even recognize the similarity in odor between this acid and the distillates from the bitter almond and the cherry laurel.

It was not until the eighties of the 18. century that bitter almond oil again received more attention. In spite of earlier observations,4) it was not regarded decidedly poisonous until so pronounced in 1784 by Joh. Andr. Murray5) of Goettingen. Following him, other contemporaries made the same statement.6)

The hydrocyanic acid content of bitter almond oil was first suspected in 1785 by the Erfurt apothecary joh. Christ. Wilhelm Reinder1) and in 1797 by Lucas2) of Armstadt. Its presence, however, was not proven until 1803 when Bohm,3) apothecary in Berlin, identified it. From that time on, bitter almond oil and its hydrocyanic acid content became the subjects of numerous investigations. Of these the reports of Schaub,4) Schrader6) and Ittner6) advanced our knowledge, but a clear understanding of the formation and composition of the oil was gained only through those of Gay-Lussac,7) Robiquet and Vogel,8) Boutron-Charland9) and finally those of Liebig and Wcehler,10) and C. Winkler.11)

1) Saladini Compendium aromatariorum. Bononae 1488. Index.

2) Expositio Joannis de Sancto Amando supra Antidotarium Nicolai incipit feliciter. In the edition with Mesue's works. Veneti 1502. fol. 228, and Additiones fol. 85-87.

3) Carl W. Scheele's Physische und chemische Werke. Translation by Hermstaadt. Vol. 2, p. 331. - Fluckiger, Arch, der Pharm. 224 (1886), 388. - Pharm. Rundschau (New York), 4 (1886), 211.

4) According to the statement made by A. Wynter Blyth in his treatise on "Poisons", London 1895, the poisonous character of the peach and almond kernels was known to the Egyptians. - Mortimer in Philosophical Transactions (London) 37 (1731), 84 and 166. - Vater, Dissertatio de laurocerasi indole venenata. Wittenbergae 1737. - Langrish, Experiences de medecine sur des animaux. Paris 1750. - Fontane, Trait6 sur le venin de la vipere, le laurier cerise etc. Fiorenze 1781 and Philosophical Transactions (London) 70 (1781), I. 210.

5) J. A. Murray, Apparatus medicaminum tarn simplicium quam prae-paratorum et compositorum in praxeos adjumentum consideratus. Gottingen 1784. Vol. 3, p. 215, 220 and 259.

6) Heyer, Crell's Chem. Annalen, Beitrage 1 (1793), 414, 415. - Gilbert's Annal. der Physik. Neue Folge 23, 220.

The separation of the hydrocyanic acid from the benzaldehyde was first accomplished by Vogel in 1822 by treating the oil with baryta water. Liebig and Woehler12) introduced the method still in use involving ferrous sulphate, ferric chloride and milk of lime, which yielded pure benzaldehyde. Bertagnini13) proposed sodium acid sulphite.

The separation of benzoic acid from bitter almond oil which has been exposed to the air was observed as early as 1823 by Stange14) in Pegau.

1) Crell's Chem. Annalen 1785, II. 443. - Gottling's Almanach fur Scheide-kunstler und Apotheker 8 (1787), 136.

2) Ibidem 18 (1797), 101.

3) Scherer's Allgem. Journ. der Chem. 10 (1803), 126. - Gilbert's Annal. der Physik 13 (1803), 503.

4) Schaub, Dissertatio medico-chymica sistens Laurocerasi qualitates medicas ac venenatas etc. Marpurgi 1802.

5) Trommsdorff's Journ. der Pharm. 11, I. (1803), 259 and 262.

6) Uber das Vorkommen der Blausaure im Ole der bittern Mande/n. Schweigger's Journ. f. Chem. u. Phys. 24, 395. - F. v. Ittner, Beitrage zur Geschichte der Blausaure, mit Versuchen uber ihre Verbindungen und Wirkungen auf den tierischen Organismus. Freiburg and Constanz 1809.

7) Poggendorff's Annal. der Phys. Neue Folge 23 (1831), 1 and 138. - Schweigger's Journ. f. Chem. u. Phys. 16 (1831), 1.

8) Journ. de Pharm. II. 8 (1822), 293. - Annal. de Chim. et Phys. 15 (1810), 29 and 21 (1822), 250. - Trommsdorff's Neues Journ. der Pharm. 7, I. (1823), 217.

9) Annal. de Chim. et Phys. 44 (1837), 352. - Liebig's Annalen 25

(1838), 175.

10) Liebig's Annalen 22 (1837), 1.

11) Repert. f. d. Pharm. II. 17 (1839), 156. - Pharm. Zentralbl. 1839, 634.

12) Liebig's Annalen 3 (1832), 252.

13) Ibidem 85 (1853), 183.

14) Repert. f. d. Pharm. I. 14 (1823), 329, 361 and 16 (1824), 80.