802 UMBELLIFERtE. 



employed in reducing the juice to the required consistence. On the 

 other hand, Harley has proved that the juice of fresh hemlock preserved 

 by the addition of spirit of wine, as in the Succus Conii of the Pharma- 

 copoeia, possesses in an eminent degree the poisonous properties of 

 the plant. 



The entire amount of nitrogen in dried hemlock leaves was estimated 

 by Wrightson (1845) at QS per cent. ; the ash at 12-8 per cent. The 

 latter consists mainly of salts of potassium, sodium, and calcium, 

 especially of sodium chloride and calcium phosphate. 



A ferment -oil may be obtained from Coniurii ; it is stated to have 

 an odour unlike that of the plant and a burning taste, and not to be 

 poisonous.^ 



Uses — Hemlock administered in the form of Svxicus Conii, has a 

 peculiar sedative action on the motor nerves, on account of which it is 

 occasionally prescribed. It was formerly much more employed than at 

 present, although the preparations used were so defective that they could 

 rarely have produced the specific action of the medicine. 



Plants liable to be confounded with Hemlock — Several common 

 plants of the order Umbelliferce have a superficial resemblance to Coniiim, 

 but can be discriminated by characters easy of observation. One of these 

 is JEthiisa Cyiiajnum L. or Fool's Parsley, a common annual garden weed, 

 of much smaller stature than hemlock. It may be known by its primary 

 umbel having no involucre, and by its partial umbel having an in- 

 volucel of 2 or 3 linear pendulous bracts. The ridges of its fruit more- 

 over are not wavy or crenate as in hemlock, nor is its stem spotted. 



Chcerophyllum Anthriscus L. (Anthriscus vulgaris Pers.) and two 

 or three other species of Chairophyllnni have the lower leaves not un- 

 like those of hemlock, but they are pubescent or ciliated. The fruits 

 too are linear-oblong, and thus ver}'- dissimilar from those of Conium. 



The latter plant is in fact clearly distinguished by its smooth spotted 

 stem, the character of its involucral bracts and fruit, and finally by the 

 circumstance that when triturated with a few drops of solution of caustic 

 alkali, it evolves conine (and ammonia), easily observable as a white 

 fume when a rod moistened with strong acetic acid is held over the 

 mortar. 



FRUCTUS AJO^VAN. 



Semen Ajavce vel Ajouain ; Ajowan, True Bishop's weed. 



Botanical Origin — Carum Ajowan Bentham et Hooker {Ammi 

 copticum L. Ptychoiis coptica et Pt. Ajotuan DC.) — an erect annual 

 herb, cultivated in Egypt and Persia, and especially in India where it 

 is well known as Ajvan or O'mam,. 



History — The minute spicy fruits of the above-named plant have 

 been used in India from a remote period, as we may infer from their 

 beino- mentioned in Sanskrit writings, as, for instance, by the gram- 

 marian Panini, in the third century B.C. (or later ? ), and in Susruta. 



Owing to their having been confounded with some other very small 

 umbelliferous fruits, it is difficult to trace them precisely in many of the 

 1 Gmelin, Cliemistry, xiv. 405. 



