I IO 



HARD WICKE'S SCIENCE- G OSSIP. 



through eating ; the dog's-mercury, but the annual 

 mercury is far less powerful in its effects, and, indeed, 

 its leaves are often boiled and eaten as a pot-herb. 



The manchineel-tree (Hippomane mancinella), a 

 native of tropical South America and the West 

 Indies, may be mentioned here, it being 2. poison ccPcbre. 

 The wonderful accounts of its power, for instance, 

 that persons have died from merely sleeping beneath 

 it, that a single drop of its juice falling upon the 

 skin burns like fire, etc., should be subject to a con- 

 siderable discount, as they are probably exaggerated. 



The cassava (Manihot utilissima) contains prussic 

 acid, and possibly another acrid principle of the 

 nature of the one found in some spurges, and these 

 render its juice highly poisonous. The roots of this 

 plant, however, are rich in farinaceous matter, from 

 which the cassava meal and tapioca are prepared. 

 These roots, which weigh thirty to forty pounds, are 

 grated ; after washing, the poisonous juice is separated 

 "by pressure, and the residue is then made into thin 

 -cakes, and baked. Prussic acid and the acrid princi- 

 ple being volatile, the remaining poison is completely 

 dissipated during the baking. Tapioca is a pure 

 starch which settles in the troughs where the cassava 

 meal is washed. It is granulated upon hot plates. 



Urtice^. — Urtica ure7is, pihdifera, etc. Al- 

 though our nettles can scarcely be called poisonous 

 plants, yet no one who has ever fallen into a bed of 

 them, and there made their close acquaintance, will 

 be surprised to see them mentioned here. As is 

 well-known, the leaves, etc., of the nettle are 

 ■covered with numerous stiff hairs. These hairs have 

 siliceous walls, as can be proved by heating a portion 

 of the leaf red-hot on a mica plate or platinum wire, 

 and their tips are bent into sharp hooks. In case of care- 

 less contact, the hairs, by means of these points, enter the 

 skin, and being very brittle they break off, and the 

 sap, which is strongly caustic, enters the wound and 

 produces inflammation. The sap of the hair or 

 "sting" of the nettle contains a volatile acid of an 

 acrid, pungent odour, similar to acetic acid, and it is 

 called formic acid, from having first been found in 

 ants. As yet formic acid has been discovered in only 

 a few plants, viz., in the leaves, bark and wood of 

 the Coniferce, in the fruits of {Sapindtis saponaria), 

 (Tamarindus Indica), the leaves of Urtica and Semper- 

 -vivum tectorum; but it exists, in all likelihood, in 

 many other plants (Dr. Wittstein). The burning 

 pain produced by the sting of the nettle is well-known, 

 but even that of our most virulent species, U. pihdifera, 

 soon abates and disappears. Their effects, however, 

 are not to be compared with those of some Indian 

 species. M. Leschenault thus describes the result of 

 touching ( Urtica crenulata) in the botanic gardens at 

 Calcutta : — " One of the leaves slightly touched the 

 first three fingers of my left hand ; at the time I only 

 perceived a slight pricking, to which I paid no atten- 

 tion, but the pain continued to increase, and in an 

 hour it had become intolerable ; it seemed as if 



someone was rubbing my fingers with a hot iron, 

 though no swelling or inflammation could be seen. 

 The pain rapidly spread along the arm as far as the 

 armpit. I was then seized with frequent sneezing, 

 and with a copious running of the nose, as if I had 

 caught a violent cold in the head ; soon after I ex- 

 perienced a painful contraction of the back of the 

 jaw. ... I continued to suffer for two days, and 

 the pain returned in full force whenever I put my 

 hand into water. I did not finally lose it for nine 

 days." There is another species of nettle in Timor, 

 the effects of which are said by the natives to last for 

 a year, or even to cause death. 



I must not fail to mention the celebrated upas-tree, 

 {Antiaris toxicaria), the juice of which is a violent 

 poison, as it contains strychnine. Its effects, however, 

 have been greatly exaggerated. "The tree is one of 

 the largest in the forests of Java. Close to the ground 

 the bark is, in old trees, more than an inch thick, 

 and upon being wounded yields plentifully the milky 

 juice from which the celebrated poison is prepared. 

 The inhabitants do not like to approach it, as they 

 dread the cutaneous eruption which it is known to 

 produce when newly cut down. But except when 

 the trunk is extensively wounded, or when it is felled, 

 by which a large portion of the juice is disengaged, 

 the effluvium of which, mixed with the atmosphere, 

 affects the persons exposed to it with the symptoms 

 just mentioned, the tree may be approached and 

 ascended like the common trees of the forest," — Dr. 

 Horsfield. 



Conifere;e. — Taxus baccata. Though the dan- 

 gerous properties of the yew have sometimes been 

 denied, it is now a well-known fact that its leaves 

 and the kernels of the fruit are highly toxic, and have 

 often proved fatal to human beings and to cattle. 

 The leaves contain an alkaloid — taxin, which dries 

 in the form of a white, loose, amorphous powder, 

 very bitter to the taste and a violent narcotic-acrid 

 poison. Several cases are known where children 

 have died through eating the berries, and the leaves 

 have often caused the death of women who had taken 

 infusions of them under mistaken ideas. The juicy 

 red cups of the berries are harmless, but the kernels, 

 as already stated, are highly poisonous. The savin, 

 {Juniperns sabina), is also toxic, and the powder 

 prepared from the dried tips of the branches, greatly 

 irritates the alimentary canal, sometimes to a fatal 

 point. 



Amaryllide^. — To this order belong the nar- 

 cissus, daffodil, snowdrop, etc., and as the beauty of 

 their flowers has made them such general favourites, 

 many readers may be surprised that every part of 

 these plants, especially in N. pseudo?iarciss!cs i (N. 

 poeticus), and N. biftorus, is strongly emetic, and their 

 very odour, though pleasant, is deleterious, pro- 

 ducing intense headache, stupefaction, and even vomit- 

 ing, if indulged in to excess. Their active principle is 

 particularly strong in the bulbs. 



