To John O'Shanassy   18 June 1862

Melbourne botanic Garden,

18 June 62

Sir

I have the honor to inform you, that having in the afternoon of Saturday 14. instant received your letter, dated 13 June,¹ desiring me to investigate by personal inspection the cause of the recent death of a number of sheep at Mr Wallace's run at Ballark, I proceeded on Monday 16. instant by the noon train to Meredith and reached Mr Wallace's station early the following morning.²

The Ballark Station is situated at one of the upper branches of the Moorabul³ River, the homestead occupying part of a beautiful basaltic valley.

Conducted by Mr Wallace to the paddock, in which the sheep had been pasturing immediately previous to their sickness, I found after a careful search of the whole ground no indication of the existence there of any herb known to me as deleterious or poisonous in the strict sense of the word. Like in all vallies rich of decomposed trap rock, the vegetation of grasses and herbs is also on this spot very luxuriant, especially at this season of the year, but is constituted only by ordinary native plants, whilst amongst the immigrated weeds I noticed only such as have become abundant in most districts of the colony, including Trifolium repens, Lolium perenne, Cirsium lanceolatum, Stellaria media, Marrubium vulgare, Erodium moschatum, Capsella bursa pastoris and Malva rotundifolia, all from Europe and the originally South African Cryptostemma calendulaceum, all widely spread over the colony.

Having learnt from Mr Wallace that the flock of sheep, of which the 87 died, had been brought from a drier upland part of his run to the deep humid valley in which the disaster occurred, and that the animals before they were brought to this paddock had been for about a day without food, my opinion became more confirmed, that the illness and death of these animals was not caused by their feeding on any particular poisonous herb growing at the spot, but most probably in consequence of the creatures after some abstinence gorging themselves with an exuberance of wet soft green food, which in its young state and taken in excess proves not unfrequently noxious to herds and flocks, especially when the latter are not accustomed to such localities, and it is not improbable that the large amount of soft and wet foliage of the Cryptostemma calendulaceum produced particularly the destructive effect on the animals, altho' at the time of my visit to Ballark a small flock of sheep, bred at the low valley of the homestead, was pasturing in the same paddock without any apparent injurious consequences.

No sheep or cattle had been kept in the paddock for months previous to the disaster; hence the growth of the weeds, augmented by the favorable season, was at the time, when the sheep were lost, most abundant. Mr Wallace informed me that under similar circumstances losses amongst his flocks had been sustained last season.

The loss of the sheep, which was the immediate cause of my visit, having taken place 2-3 weeks ago, it was beyond possibility to institute a very satisfactory examination of the stomachs of two of the perished animals, kept by Mr Wallace for the purpose. They did however not present any marks of internal abrasion, indicative of the action of metallic poison, nor did I discover on application of the ordinary chemical tests any traces of such poisons as usually are employed for dressing sheep, altho' many instances are on record of the incautious use of arsenic and mercury preparations for sheep-washing, which are often allowed to saturate the ground and may remain as anorganic poisons, an everlasting danger of destruction on such spots.

In examining the stomachs of the sheep I found the rumen and reticulum gorged with a semiliquid pulp of green food. The psalterium and abomasum were also more or less filled with triturated herbs, which on account of their softness would be rapidly regurgitated. But neither these stomachic cavities nor the oesophagus nor the pylorus showed traces of the action of metallic poison. The specific recognition of the herb in the stomachs of the animals would under any circumstances be equally out of the question as the recognition of any peculiar organic poison.

Mr Wallace informed me, that the sheep were removed after a nights stay from the paddock and that a few days after their removal no further deaths occurred amongst the flock. The internal application of a spoonful of mustard and a spoonful of unmixed tar to most of the animals, which died, was evidently calculated to increase the inflammation, consequent on the overcramming of these sheep, as the above remedies would act as strong irritants, whilst under the circumstances emetic evacuants and demulcents would be indicated in order to remove the inciting cause of the disease and to involve the inflamed membranes and linings with an oleaginous and mucilaginous covering. Such remedies would be specially indicated by any of the Gentlemen of the veterinary profession, when consulted on the subject.

I am gratified to be enabled to dispel the fears of the settlers in the locality, that a new noxious weed had sprung up on their runs, in as much as it is apparent that the danger of the reoccurrence of losses similar to those in Mr Wallace's flocks might readily be obviated by keeping the flocks at the early spring season in higher ground.

Should the cramming food, consisting of Cryptostemma calendulaceum have been, as I suppose, the primary cause of the disaster in this instance, then its effect must be ascribed to mechanical irritation, since this plant has under ordinary circumstances not proved deleterious to herds and flocks and would become only dangerous when it forms in moist weather the momentary prevailing and rapidly devoured food of stock unaccustomed to this plant, similar hurtful actions of green food, when consumed immoderately, and in wet weather being by no means of rare occurrence.

As the Cryptostemma has widely spread over the country, the ready opportunity is offered every where to investigate its varied effect on pastural animals.

I may add, that after explaining my views, Mr Wallace fully concurred in the lilekihood of their correctness.

I have the honor to be,

Sir,

your most obedient and humble servant

Ferd. Mueller, M.D.

Gov. Botanist

The honorable the Chief Secretary

&c & &⁴

Capsella bursa pastoris

Cirsium lanceolatum

Cryptostemma calendulaceum

Erodium moschatum

Lolium perenne

Malva rotundifolia

Marrubium vulgare

Stellaria media

Trifolium repens