PLANTS REPUTED POISONOUS TO STOCK.

NATIVE TOBACCO.

AMONGST the native plants of Australia known to be poisonous to stock, one said to be the most noxious is the Native Tobacco, found growing in one form or another over the whole of the Australian Continent. It belongs to the order Solanaceæ, and its botanical name is Nicotiana suaveolens, Lehm., Hist. Nicol. 43, Flora Austr. IV. 469.

It is an erect annual or biennial plant from 1 to 4 feet in height, and is usually covered with viscid hairs. The lower leaves are the largest, often reaching to 1 foot in length, the upper ones being, as shown in our illustration, narrower and usually stalkless, sometimes clasping the stem with their base. In one variety (parviflora) only about 1 inch long, and not spreading much at the mouth; in another variety (longiflora), usually met with inland, the flowers are several inches long, and expand into an open flower like a petunia, or Marvel of Peru. Capsule ovate, slightly pointed, and full of small seeds.

There is a general consensus of opinion amongst stockowners that this plant is poisonous to stock. It is credited with causing the deaths of many travelling sheep. Mr. Hutchison instances a case which came under his notice of 300 rams being poisoned by it. The effects upon sheep are-drooping head, dull eye, swollen tongue, and, a few hours before death, paralysis of the loins.

Dr. T. L. Bancroft, in a note communicated to the Royal Society of Queensland, in January, 1886, has shown that this plant is undoubtedly poisonous, and this is due to the presence in it of an alkaloid having all the physiological properties of the nicotine of the true tobacco plant.

The above description of the plant, and the illustration, are from the publication on Plants Reputed Poisonous and Injurious to Stock," by Messrs. F. M. Bailey, Government Botanist, and P. R. Gordon, Chief Inspector of Stock.

A remarkable circumstance connected with this and some other reputed poisonous plants is that, whilst in one part of a district it is declared to be deadly to stock, in another, at no great distance, it is looked upon as an excellent fodder.

The late Mr. Jacob Low, who was undoubtedly a first-class judge of fodder plants suitable for sheep, stated that the Native Tobacco was splendid sheep feed, and the animals grazing on it became rolling fat. Yet we are told by another good authority that hundreds of sheep have died from its effects, whilst a scientific man like Dr. Bancroft also gives testimony to its deadly qualities. The question arises, "What can one believe when such conflicting evidence is given by men who ought to know what they are talking about?" It would seem that the only plan by which certainty on such points can be attained would be to make practical experiments, by growing the plants and offering some sheep as a sacrifice in the general public interests.

We have lately been informed that all wattle-trees possess very poisonous qualities. Who would believe that a wattle-tree could be poisonous? "Yet there is not the slightest doubt" says Dr. Lauterer, in a paper read before the Royal Society of Queensland, "that the Black Wattle (Acacia Cunninghamii), although quite innocent when it blossoms and after it has borne fruit, contains a large amount of saponin in the unripe pods, and a small amount of it even in the leaves and in all green parts of the plant. Saponin has been found in Acacias as far back as 1871.

"In 1886 Dr. T. L. Bancroft, in a scrub on the Gregory River, by accidentally biting the pod of Acacia delibrata, found that it had a very disagreeable, acrid taste. It seemed so strange that an Acacia should have any but an astringent taste that a quantity of the pods were gathered with a view to ascertain if they contained a physiologically active substance. The result of Dr. T. L. Bancroft's investigation was the discovery of saponin in the pods of Acacia delibrata.

"After Dr. Bancroft, Mr. M. Thiel, in 1889, drew attention to the occurrence of a variety of saponin (called moussenin) in the bark of the Abyssinian Acacia

Anthelmintica, which is used as a taenicide, or remedy against tapeworm, by the natives, by whom it is alleged to be more effective for the purpose than Kuosso, whilst less disagreeable in taste. Many of the 320 species of our Australian Acacias have been found by me to contain saponin all the year round-e.g., the New South Wales species (Acacia verniciflua, Cunn.), which is called 'dogwood' by the bushmen around Bathurst, and which is used as a fish poison by them.

"Other species are quite free from saponin at certain times of the year, and rich in it at other times, such as Acacia Cunninghamii and A penninervis. These Brisbane black wattles blossom in the spring month of September, and show the pretty flowers for about a fortnight. After fertilisation has taken place, the pods begin to grow. In about 3 weeks they attain the length of 2 inches, with a narrow width and twisted appearance which has gained them the name of 'wattle curls' from the school children in the bush. In this state the pods have a purely astringent taste. They contain about 20 per cent. of catechutannic acid, and not a trace of saponin. They continue to grow during the fourth week. The tannin then disappears gradually, whereas saponin by degrees takes its place. The astringent taste gives way to an extremely nauseous, acrid, and disagreeable sensation on the tongue, especially on the back parts and the sides of it. This taste creeps over the whole tongue, if even only the tip of it is brought into contact with the bruised pod. It continues long, and leaves a slight sense of numbness on the tongue. If the juice of the pod is allowed to reach the back part of the tongue, it seems to irritate some branches of the nervus vagus, as it produces a short hacking cough, and the same sensation as when the inside of the ear or the skin behind the ear is scratched with a sharp instrument.

"A watery infusion of the 'wattle curls' froths and forms a lather, when agitated, like a solution of soap, and this property is due to the saponin, which has been obtained pure by me from the pods. The tannin has to be removed first from the inspissated infusion or watery extract by shaking with ether, which does not dissolve the saponin. Chloroform then takes out the saponin, which can be estimated quantitatively after evaporation. It is a white powder, and is dissolved by sulphuric acid with a red colouration. I found 3 per cent. of saponin in the unripe pods of Acacia Cunninghamii. Saponin is a strong poison for the muscle and the nerve, producing anesthesia very much like the cocaine; but, besides this, it acts as a powerful irritant. I have seen many

cases of so-called 'sandy blight' of the eyes of bush people at times when there was no sand and no wind, and in people where every suspicion of a specific infection was excluded. In one case it was easy for me to trace the real cause. The bushman, who suffered from a very acute conjunctivitis, with swelling of the lids, had the fingers of both hands covered with a sticky substance, which, on being washed away in a small basin, caused a very marked frothing in the water. The sandy blight' of the woodcutter was caused by the juice of the wattle curls,' brought in contact with the eyes by wiping them with the hand.

"The hypodermic injection of the extract of only one unripe pod of Acacia Cunninghamii into the arm of a person caused great pain, swelling, and redness of the injected spot, nausea, and shivers; the extract of two pods caused headache, formications in the legs and arms, and paralysis of the accommodation of the eye and mydriasis. It is beyond doubt that the juice of six wattle pods, hypodermically injected, will kill a man. Injected into the leg of a frog (Hyla coerulea), it produced total insensibility of the leg against even the strongest local irritation, and total paralysis of the muscles."

As the commercial saponin, in doses of 2 drachms, is a deadly poison to dogs, it may well be supposed that a dose of 6 drachms would kill a man; and this quantity is contained in the extract from only 2 lb. of "wattle curls."

There is one point left to be discussed-the occurrence of saponin in the Acacia leaves at the time when it is found to occur in the pods. Is it formed in the leaves, and does it migrate to the pods? Or, is it formed in the pods, and does it go to the other parts of the plants from there? The question is a

difficult one; still, an answer is given (1) by the fact that saponin makes its appearance first in the unripe pods, and only after some days in the leaves; (2) the analogy with similar processes shows that tamic acids in many instances are found in unripe fruits, to be transformed into sugar when the fruits ripen, as in the case of the banana, which is rich in gallotannic acid, and even when cut off the tree will lose nearly every trace of tannin, and get rich in sugar and vegetable slime.

In the case of the Peach-leafed Poison Bush (Trema aspera) which has been denounced by some as injurious to stock, it would seem that the difficulty with this plant lies, not in poisonous properties, but in the indigestibility of the fibrous leaves. The fibre remaining in the animal's stomach becomes hardened into balls, in the same manner as hair is found matted and hardened in the stomach and intestines of cows, horses, and pigs, eventually causing the animal's death.

Economic Botany.

BY F. MANSON BAILEY, F.L.S.,
Colonial Botanist.

THE KEI APPLE (ABERIA CAFFRA, Hook).

(PLATE CXV.)

A LARGE shrub, native of the Cape of Good Hope and Kaffirland, furnished with strong, straight, long spines, and rather small obovate leaves. The round lemon-coloured fruit, which is about 1 inch or more in diameter, has an agreeable somewhat acid flavour, and makes a most palatable preserve. A few weeks ago Mr. Charles Harries called at my office with a few fruits of this plant, of which he desired the name, &c. I recommended him to try it as a preserve, mixed with melon, for jam-making; a few days afterwards, he sent me a small pot of excellent jam, accompanied by the following note:- Since seeing you on Friday last about the Kei apple, the information which you so kindly gave me concerning the apple's use for making jam, &c., has been put to the test, and I forward you herewith a small pot of jam which was made from the 'apple' and the melon which I was describing to you. According to the colour of the jam, you would think that colouring had been used, but I can assure you that none was used in making it. I am very sorry I did not come to you sooner for the information, as the crop of fruit is just over and gone to waste." The melon spoken of is the White Gourd (Benincasa cerifera), a fruit equally as useful as the pie-melon. In an unripe state, the fruit of the Kei apple is used for pickling.

The plant is one of the best known for hedge-making, for which purpose it must be raised from seed, as it does not strike readily from cuttings. In planting for fruit, layers from female plants should be made. For fertilisation purposes, one male plant would supply pollen sufficient for 20 or 30 female ones.

Although as previously stated, the fruit is a useful auxiliary in the manufacture of preserves, its cultivation on a large scale for this purpose cannot be recommended. The plant was introduced into England in 1838, by the Messrs. Loddiges, and one of these plants (a male) was brought out by my father, who left England for South Australia in the same year.