Chemical Preparations and Drugs. 101 



in quality. It is advisable to place the plants in rows 3 feet apart and the latter must 

 be l 1 / 2 to 2 feet apart. A mixture of ammonium sulphate, acid phosphate and potassium 

 sulphate is recommended as manure. It is imperative to distil the herbs in a fresh 

 state, immediately after having been cut, because during the drying process not only 

 oil is lost, but the leaves also fall off easily which causes a further loss in oil. The 

 best time for gathering the plants is when they begin to develop their blossoms, but 

 before they are in full bloom. This statement is illustrated by the following table: — 



Plants just beginning to send up flower stalks . 0.34 per cent, of oil with 72 per cent, of phenols, 



Budded stage 0.30 „ „ „ „ „ 76 „ » „ , 



Full flower ■ . . 0.24 „ „ „ „ „ 74 „ „ „ , 



Flowers fallen 0.18 „ , „ „ , 74 „ „ „ „ . 



For distillation purposes, Hood recommends the same apparatus used for the prod- 

 uction of peppermint and spearmint oil. It is even possible to obtain a further supply 

 of 0.114 per cent, of oil with 95 per cent, phenols from the distillation water. It is 

 occasionally advisable to cut the herbs, but this has no effect on shortening the time 

 necessary for distillation. 



Hood recommends fractional distillation for isolating the thymol from the oil. The 

 phenols of the oil consist almost entirely of thymol and contain hardly any carvacrol ; 

 the non-phenols consist in the main of cymene. Thymol can be separated easily in 

 a pure state from the oil by fractionating it; Hood obtained from an oil that contained 

 72 per cent, of phenols by distillation 64.3 per cent, of thymol. He does not refer at 

 all to the melting point of thymol. The distillation residue consisted of a thick, tarry 

 mass which has hitherto found no application. 



A good mouth wash must prevent the growth of the bacterium Leptothrix ouccalis 

 which is the cause of the formation of tartar and probably also of pyorrhoea. For this 

 purpose, the teeth must be treated as often as possible with a mouth wash by the 

 aid of a tooth brush which purpose is best served according to H. P. Goodrich *) con- 

 centrated watery thymol solution. It has a pleasant taste, acts as a strong antiseptic 

 and in a less irritating manner than carbolic acid, neither does it act as an acid nor 

 does it. possess the corrosive effect of the above-mentioned acid. Besides, it is quite 

 harmless if swallowed by mistake. The following compounds are less effective accord- 

 ing to Goodrich: — boric acid, emetin hydrochloride, iodine, hypochlorite solution, 

 peroxide of hydrogen, potassium permanganate, and flavine. 



While studying substances which act hcemolytically, especially extracts of plants, 

 it has often been the practice to to treat the solutions with thymol. This is not ad- 

 missible, as P. LaviaHe and A. Aubry 2 ) have found, and has in consequence often led 

 to false statements because thymol itself acts as a strong hemolytic. The hemolytic 

 action of thymol depends on its concentration, saturated solutions having a stronger 

 action than weaker ones, besides which the effect is dependant an the temperature 

 and on the presence of various acids. 



Vanillin. On page 80 Of our last October Report we discussed a publication by 

 Constantin and Bois on the three varieties of Vanilla planifolia which are cultivated 

 on Tahiti. This paper has now been supplemented by a further publication of the 

 same authors 8 ). 



2 ) British medical Journ. 1917, I. 473; Chemist and Druggist 89 (1917), 376. — 2 ) Bull. Sciences pharmacol. 

 23 (1916), 193, 266. — «) Compt. rend. 163 (1916), 466. 



