1 oz. to every gallon of water. This fluid should be held in a wooden tub. Potatoes that have been derived from a distant source should not, by reason of this circumstance, be regarded as necessarily "clean."

9. The immediately preceding suggestion has reference to cases in which the seed, though possibly carrying the germ, is not itself diseased. But the latter condition may occur, and it should therefore be subjected to a very close scrutiny, in order to discover whether it is sound or otherwise; and, if unhealthy, discarded and destroyed. The following appearances will indicate the occurrence of the malady in a latent or temporarily undeveloped state—

(a) A wetness at the eyes, accompanied by a slight exudation of a frothlike matter, when the seed is kept warm and damp, as, for instance, by covering it with a wet sack.

(b) Sunken brown or blackish-brown areas on the surface, or (in whiteskinned potatoes) patches of dark discolouration showing through the outer skin.

(c) Adherence of soil to the eyes, which soil, when removed, will appear to be covered, where in contact with the bottom of the eye, with a greyish glossy film (dried gum).

(d) A potato being cut across with a sharp and clean knife, and the sap upon the exposed surface being allowed to dry off, small droplets of a whitish, glossy, pus-like matter will appear at places along the course of the line or ring that runs a short way within the margin nearly parallel thereto, except where it sends an extension to any eye that may be cut through. These droplets are especially discernible when the section is looked at obliquely, when their bright lustre brings them into view. A small patch of decay present along the indistinct line alluded to, or between it and the outside of the tuber, may also be usually regarded as indicative of the presence of the disease. Potatoes cut in preparation for planting should always be examined with the object of detecting such appearance in view, and suspicious sets rejected and burnt.

10. These recommendations as to treatment are based on a recognition of the cause and fundamental nature of the disease as set forth in general terms in the first section of the report, and that have been revealed for the first time by the writer as the outcome of patient research. They may be supplemented by others that it is within the capacity of the intelligent farmer himself to devise, now that he has been enlightened on these points.

BIBLIOGRAPHY,

A "Preliminary Report on a New Potato Disease prevalent at Ravensbourne, at Corinda, and in other parts of Southern Queensland," by the writer, was submitted by him on 27th April, 1894. This contained sections dealing with the following subjects:-Symptoms; Mode of Occurrence; History of Occurrence; Amount of Injury; Other Outbreaks; Cause (including description, mode of occurrence, and development on artificial media of the bacillusillustrated by figures); Conclusion (recommendation as to treatment). This memoir was neither printed at the time nor subsequently, but a summary of it was published by the Department of Agriculture, and this forwarded to different papers and institutions. This summary appeared in the various Queensland daily and weekly journals, including the Queenslander of 12th May. It was also printed in the "Annual Report, Queensland Department of Agriculture, 1893-4, Brisbane, 1894." Again, an abstract of it, written by Professor Schimper, of Bonn, was contributed to Dr. Paul Soraurer's Zeitschrift für Pflanzenkrankheiten for 1895 (op. cit. Band V., pg. 234). Further, Professor B. T. Galloway (Chief of the Division of Vegetable Physiology and Pathology of the U.S. Department of Agriculture), in acknowledging it-the receipt-at the time stated as follows:— "I have read with interest the account of the New Potato Disease; and while I cannot say positively that what you have described occurs here, I think it very

probable we have isolated cases of it every year. The disease you describe seems to be very similar to one attacking the tomato in various parts of the country, and known here under the name of 'Southern Tomato Blight,' in. litt.

18-7-1894.

In the spring of 1895, the Assistant Pathologist (Dr. Erwin F. Smith) in the department so ably presided over by Professor Galloway-prompted, it may be, by the writer's discovery, with whom also he had been in communicationcommenced an extensive series of microscopic examinations and plant inoculations in the laboratories and greenhouses of the U.S. Department of Agriculture in Washington, made field observations in August, 1895, and resumed his laboratory investigations in the following year. As the outcome of this extended research, he published an important paper entitled "A Bacterial Disease of the Tomato, Egg Plant, and Irish Potato (Bacillus solanacearum n.sp.)," as Bulletin 12, Div. of Veg. Phys. and Path., U.S. Dep. of Agr. Dec. 1896.

In a foot-note at the commencement of his memoir, Erwin F. Smith writes:-" A bacterial disease of potatoes and tomatoes has also been reported by Henry Tryon from Queensland, where it is said to be very destructive." He then gives references to the summarised version of the report already alluded to, and adds :-" In the article on Gumming of Cane,'* the potato and tomato organism is called Bacillus vascularum solani, and no description is given, and I have not been able to find any, or to decide from the brief account of symptoms whether or not the Australian disease is identical with our own.' To this it may be added that, having carefully studied the statements in E. M. Smith's able memoir pertaining to the American disease, and repeated some of the experiments that relate to the morphological and physiological characteristics of the bacillus referred to therein, and that go more fully into this aspect of the subject than had previously been attempted here, the conclusion-previously suggested by Professor Galloway-that the American and Australian diseases are identical. is fully borne out, a verdict that any investigator, endowed with but little less of the spirit of scientific caution exercised by E. M. Smith, might have pronounced even in the meagre light of the information, derived from this Queensland source, that partially illuminated the question.

* The paragraph alluded to occurs on page 14 ("Gumming of Cane," Department of Agriculture, Brisbane, June, 1895), and is as follows:-"I may also add that, in a new potato disease that I have lately reported upon, and which I have had an opportunity for reinvestigating in the course of this inquiry, microbes, scarcely distinguishable from those that are met with in diseased sugar-cane, and which I have designated Bacillus vascularum solani (the microbe occasioning 'gumming' of sugar-cane having already been entitled Bacillus vascularum by N. A. Cobb), occurs under precisely the same circumstances-i.e., clogging up the vessels of the stems, roots, and rhizomes, and, in the initial stages of the disease, nowhere else; and that seedling examples of another solanaceous plant, viz., the tomato-raised in soil in which these microbes have been liberateddevelop a disease apparently quite similar to that which the potato plants, from which they have been derived, present, and which, amongst other features of resemblance that it shares, has these identical microbes clogging up its vessels also. So that the connection between the microbes and the occurrence of the disease with which they are associated in both plants is that (of cause and effect.

SOME fourteen years since the writer commonly remarked the presence of a large and peculiar slug in the Brisbane Botanical Gardens, which was then to be found as it traversed the footpaths, early in the day during the summer months, especially

if wet prevailed. How long prior to this it might have been observed there cannot perhaps be now ascertained. It is stated, however, by W. French, one of the staff of that establishment, that it was to be met with there already in 1883, in which year his official connection with the institution commenced. Two apparent varieties-one nearly black, and the other pale yellowish-brown-were thus early recognisable.

Beyond the fact that they represented the genus Vaginula, nothing was known of their systematic relationship until 1889, in which year a former scientific colleague, C. Hedley, submitted specimens to D. F. Heynemann, who had not only, in conjunction with Fischer, written a monograph on the genus, but had also described a related slug, now known as Atopos australis (Heynemann), Simroth, from this colony. Heynemann in due course referred the specimens to Dr. H. Simroth, of Leipzig University, who pronounced the hitherto regarded varieties to represent two different species, that he named respectively Vaginula Hedleyi and Vaginula Leydigi; the latter specific title being a tribute to a venerated teacher, Geheimrath Leydig.

BIBLIOGRAPHY.

66

The

NOTE. Dr. H. Simroth has devoted two memoirs to the technical description of these species of Vaginula; both are entitled "Über einige Vaginula-Arten." one is published in the Zoologischer Anzeiger for 1889 (op. cit. vol. xii., pp. 551-556 and 574-578, Leipzig, 1889), and the other in the Zoologischen Jahrbüchern for 1891 (op. cit. Abth. f. Syst., vol. v., part 5, pp. 861-906, plates xlix.-lii.). The Anzeiger paper is fully summarised in the Journal of the Royal Microscopical Society for 1890, in a note entitled "Some Species of Vaginula" (op. cit. pp. 21-22), and is also referred to by C. Hedley in a paragraph On laginula Leydigii and V. Hedley, Simr.," in Proceedings Linnean Society of New South Wales for 1891 (op. cit. ser. 2, vol. 5, p. 897). Dr. Simroth's paper in the Zoologischen Jahrbüchern has unfortunately not been seen by the writer, but he is informed by the lastmentioned authority that it is the paper in chief"; also that the plates reproduce a series of coloured and uncoloured drawings (the work of C. Hedley himself) of the animals, their eggs, &c., and exhaustively illustrate the anatomy-most fully dealt with also in the text. The student of the genus may also consult, with great profit, Dr. C. Semper's Land Mollusken, part vii., in vol. iii. of his Keisen im Archipel de Philippinen, Wissenschaftliche Resultate" (op. cit. pp. 291-327, plates xxiv.-vii.), in which is embodied descriptions of the species of Vaginula contained in European collections at a time just prior to the date of Dr. Simroth's first paper.

66

INCREASE.

66

For some years subsequent to the time at which these slugs were first remarked as occurring in the Botanical Gardens they remained apparently quite restricted to the limited area that these embrace, but already in 1895 they had extended in the Brisbane district far beyond them, for at that date they were very numerous on the hills immediately to the south on the opposite side of the river, especially in certain gardens on Highgate Hill and in Musgrave Park. At the present time they have reached almost all the suburbs of the city; thus it has been certified on good authority that they are not only at Milton and Toowong, but that "they extend from the Junction on the Ipswich road, all around about West End to as far as the Albion, if not further"; also, that they are very plentiful at the Acclimatisation Society's Gardens, Bowen Park." Where they occur also they are, as a rule, to be met with in immense numbers. In the parks of North Brisbane, during warm wet nights, they may be encountered in such numbers in the grass that every square foot of surface seems to be occupied by one or more. Mr. M. B. Bernays also has informed the writer that where he is living near Highgate Hill it is usual to see, after nightfall, regiments of slugs, of at least three varieties, making their way from their haunts towards tender plants of all descriptions, be they vegetables or flowers. Within the last week (second week in April) I have collected as much as seven measured quarts of these vermin, and apparently have made very little progress towards their annihilation."

Ein guter Conchyliolog und speciell über Nachtschneckenanatomie" (H. Simroth).