422 Botanical Society of Edinburgh. 



The druggists here, dissatisfied with this English bark, have got 

 the officinal substance imported from America. It is now brought 

 in 1 lb. packages, as made up in America ; is in small fragments not 

 more than an inch long, is free from epidermis, and otherwise corre- 

 sponds with Wood and Bache's description. 



Dr. Maclagan made various experiments with different samples of 

 the English bark, to determine whether or not it would yield any 

 hydrocyanic acid ; but though he subjected four separate portions to 

 distillation, he could not obtain from it the least trace of this active 

 principle. It is obvious, therefore, that the bark of English growth 

 wants one of the most important constituents of the American bark, 

 and is comparatively of little value. Dr. Maclagan' s trials of it in 

 practice had not tended to raise it in his estimation. It did not ap- 

 pear to have any special advantage over other bitters of which there 

 are plenty, and from the great quantity of altered tannin and extractive 

 which is taken up in the infusion, it even appeared frequently to 

 disagree with the stomach. From the American imported bark, 

 however. Dr. Maclagan separated hydrocyanic acid in small quantity 

 by distillation. It made a very bitter infusion, and deposited some 

 tannin on cooling. Alcohol appears to take up more of the bitter, 

 and water more of the astringent matters of these barks. Even the 

 American bark, however, which is now in the best shops substituted 

 for the English, does not appear to possess that combination of 

 sedative and calmative action with tonic power, for which it is pre- 

 ferred in the United States, and did not appear to be so useful, and 

 cannot be so uniform in quality, as a combination of some of our 

 common bitters, such as Colombo with hydrocyanic acid, a form of 

 prescription which had proved very efficacious in his hands. In fact 

 the want of calmative property had led to its being generally prescribed 

 with hydrocyanic acid added to it, and thus it did not appear to 

 Dr. Maclagan to have any special advantages. 



The fact that the bark of the C. serotina yields hydrocyanated oil 

 has been established by the experiments of Procter quoted above ; 

 that the bark of C. Padus yields hydrocyanic acid also has been long 

 known. Dr. Maclagan had made some experiments with the fresh 

 twigs of C, Virginiana from the Botanic Garden of Edinburgh, and 

 found that it yielded hardly any volatile oil, not enough to render 

 the distilled product milky, but it gave a certain amount of hydro- 

 cyanic acid. 



* From two ounces of fresh bark distilled with water, he obtained a 

 distillate which gave 0*08 of real hydrocyanic acid ; but the decoction 

 contained little tannin, was barely bitter, and had rather a sweetish 

 taste. It was obvious, therefore, that the bark of the shrubby C. 

 Virghiiana would be of little use as a medicine. 



Dr. Maclagan likewise examined the bark of C. Padus. From 

 two ounces of the fresh bark he got by distillation a fluid which had 

 a distinct layer of oil on the surface, and contained ()"2G of real hy- 

 drocyanic acid, or more than three times the amount got from C. 

 Virginiana. The decoction of C. Padus also was richer in tannin, 

 and was strongly and agreeably bitter. Dr. Maclagan had not had 



