If a cone of Araucaria be examined, it is manifest that the apparent scales of the cone are serially homologous with the leaves of the shoot which the cone terminates. As Dr Lindley has pointed out (Veget. Kingdom, p. 227), these scales "have actually the same structure as the ordinary leaves;" there is, indeed, a gradual transition from the one to the other. Now, under the ordinary view, the difficulty at once arises; since the "scales" of Araucaria are thus the leaves of the main axis of the cone, how can they correspond to the scales of an Abies, which (whatever view be taken of their nature), are certainly not the leaves of the main axis of its cone?

This difficulty may, I think, be removed, if we direct our attention to the small scale-like body (figs. 3 and 4, sc), situated

Fig. 3. Bract and scale from Araucaria imbricata. b, Bract; sc, scale; P, pistil; o, orifice of pistil. (After Richard.)

Fig. 4. Longitudinal section in the mesial plane of bract and scale from a

young cone of Araucaria (Eutassa) excelsa: b, sc, p, and o as in fig. 3; nu, "nucleus." From a dried specimen remoistened.

Fig. 5. Diagram showing the supposed constitution of the cone-scale in Araucaria. The different parts are represented as detached from one another. The shaded portion represents the axial structure. b, Bract; sc, axillary scale, nu, "nucleus" (the termination of the axis of the scale ?); c, carpel.* *The covering of the "nucleus " in Araucaria is here provisionally termed a carpel. It may, however, be open to question whether this pistil (the soNEW SERIES.-VOL. XIII. NO. II.-APRIL 1861. 2 c

near the apex of the apparent-scale in most of the species of Araucaria. This "squamula" is most distinct in those Araucarias termed Eutassa. It is very small in A. imbricata, and is absent in A. brasiliensis. It is generally regarded as a process or appendage of the "ovule."† This small scale-like body must, I conceive, be regarded as the representative of the conescale of an Abies. We are prepared for its small size, when we consider the relatively small size of the scale in Cunninghamia when compared with the scales of Abies or Pinus, and for its extensive union with the bract by what occurs in Cunninghamia, or Abies pectinata. If this supposition be adopted, the structures in the cone of Araucaria become at once intelligible, and capable of strict comparison with those in our ordinary cones. What have been termed scales in Araucaria should now be considered as bracts, to which the scales proper are extensively adherent.

In Dammara the cone is provided with "scales" so-called, each of which gives origin, about or a little below. the centre of its inner surface, to a solitary unequally-winged female flower ("ovule"). These scales have, so far as I am aware, been universally considered as true scales desti- Bract (cone-scale) of Dammara

tute of bracts. This, I believe, is exactly the reverse of the truth, and on the following grounds :

Fig. 6.

1st, These so-called scales are not placed in leaf-axils. 2d, In the allied genus Araucaria we have the true scale very much reduced in size. Its free portion actually dis

called adnate or adherent ovule) may not really be of the nature of an inferior germen; in which case the "carpel" would necessarily be considered as consisting for the most part, if not altogether, of an axial structure. This point, however, can only be determined by examination of the development.

* I have not had the opportunity of examining the cones of Araucaria brasiliensis. Through the kindness of Professor Balfour, I have examined a cone of A. (Eutassa) excelsa, from a scale of which I made the section represented in fig. 4. The transition between the leaves of the shoot and the so-called scales (bracts) of the cone is particularly well seen in young specimens.

†See Richard, Mémoires, &c., p. 87; also, Endlicher, "Synop. Conif.," p. 184.

appears in Araucaria brasiliensis, in which we have a condition almost exactly similar to what, I believe, exists in Dammara. If my supposition regarding Araucaria be correct, it cannot be imagined that Dammara, otherwise so nearly related, should differ so widely from Araucaria and the ordinary Abietineæ as it would necessarily do if the generally received opinion were correct. Thus, I conceive, that in Dammara we have, as in Araucaria brasiliensis, bracts with which the axillary scales (so to speak) are completely incorporated. On cutting the cone-scale of Dammara longitudinally, the female flower (" ovule") is seen to be supplied with a vascular bundle, which runs up from the base of the "scale," curving at its upper end to enter the inverted pistil. This vascular bundle is quite distinct from the mesial vascular bundle of the so-called scale, running parallel to it, and like it, in the mesial plane. This circumstance, although it does not of itself necessarily prove anything, yet tends to confirm the idea that the pistil of Dammara does not originate from the scale so called, but is only connate with it by its peduncle.

I feel satisfied that no one, who will without prejudice reflect upon the matters which I have just now been discussing, can fail to be convinced that the above is the only possible method by which the structures in Araucaria and Dammara can be reduced to a common type with our ordinary Coniferæ.*

There is one other question of interest in relation to the general Araucaria and Dammara to which I may allude, although it is one which can only be determined with certainty by an appeal to their developmental history, viz., are their solitary pistils (so-called ovules) developed on tertiary axes, as in Abies, &c; or (what is probably the case) are they developed upon the extremity of the secondary axes-the "scales," or axillary shoots of the bracts? Upon this latter supposition we probably have in Cunninghamia a transition form between Abies, Pinus, &c., and Araucaria, with its allies. In Cunninghamia it is probable that, in addition to the two late

*It may be observed that the above reasoning is not necessarily depen lent upon any considerations as to the nature of the so-called ovules (pists of Baillon), or of the squamæ fructiferx.

ral flowers of Abies, &c., a terminal flower is developed at the extremity of the axis of the scale. In Araucaria, &c., the two lateral flowers are not developed, leaving only the terminal one.

If there is any truth in this idea, it might be predicated, that of the three female flowers on the scale in Cunninghamia, the central one would be found to be developed first, the two lateral subsequently, a state of things resembling the centrifugal development of the female flowers in Cupressus, so clearly detailed by Dr Baillon.

The union of the bract with the axis of inflorescence in Cunninghamia, and with the peduncle in Araucaria and Dammara, is perfectly comparable to the connation of the axis of inflorescence with the leaf from whose axil it originates, in Tilia and Helwingia.

On the Acrid Fluid of the Toad (Bufo vulgaris). By JOHN DAVY, M.D., F.R. S. Lond. and Edin., &c.*

The fluid, the secretion of the cutaneous glandular structure of the toad, is a subject on which many different opinions have been entertained. The popular notion, handed down from a remote period, has always been that it is a poison. That notion some years ago was held to be a mere vulgar prejudice, and was pointed out as altogether an error, by so high an authority as Baron Cuvier. In 1826 my attention was given to it, and the result of the inquiry was, that the fluid is simply acrid, an irritant, offensive as such, but not a poison. Subsequently, it was examined by two French physiologists, MM. Gratiolet and S. Cloez. The conclusion they arrived at was, that the secretion is a powerful poison, in some instances occasioning almost immediate death.§ Later still, Mr George Rainey engaged in the inquiry, and his re

*Read before the Royal Society of Edinburgh, 18th March 1861. Le Règne Animal, ii. p. 94.

Phil. Trans. for 1826.

§ A notice of these experiments is to be found in the " Spectator" newspaper of 28th August 1852.

sults, it would appear, are opposed to those of MM. Gratiolet and Cloez, agreeing perfectly with those I had before obtained.

Recently, viz. in August last, I made further trials of the fluid. The animals experimented on were a kitten, two days old, a fowl, and a slug (Limax ater). The toad, from which the fluid was collected was of ordinary size. It had been in confinement three days. The fluid was obtained by scraping the glandular surface secreting it with a knife. In each trial it was applied to a small wound in the cutis; and not merely applied by simple contact, but inserted and rubbed in. The animals were watched for twenty-four hours. The results were entirely negative. Neither the kitten, the fowl, nor the slug appeared to. suffer in the least. The kitten did not refuse milk, although the part chosen for the experiment was the nose; nor had the fowl its appetite impaired;-its head was the part selected for the trial.

These results agreeing with my former, and with those obtained by Mr Rainey, I shall not attempt to reconcile with those, so opposite, of the French physiologists.

I do not think that any material difference of quality of the fluid could have arisen from difference of climate or of season. My first experiments were made in the Ionian Islands; and the viscid fluid used-at the time copiously secreted—was acrid and irritant. The fluid last employed had the same bitter taste, and, applied to the tongue, excited the same kind of sensation as before experienced-an acrid one, but not severe, though of some hours' duration.

I have stated, in my early account of the fluid, that it was neither alkaline nor acid, it having had no effect in changing the colour of litmus or turmeric paper. MM. Gratiolet and Cloez say that they found it alkaline. The fluid which I

have recently examined has also been neutral, similarly tested. They mention having kept it twelve months without its losing its activity. If kept in a damp place, might not its alkaline

* Quarterly Jour. of Micro. Science, No. 12, for July 1855.

During that time it had voided a good deal of excrement. The focal part consisted chiefly of the wings of insects; the liquid, the urinary part, contained a little urea.