that a friend of his, a banker near London, finding himself constantly confounding red and black ink with each other, had a bottle of a different shape provided for each, as a safeguard against further mistakes. These facts may seem trivial, but they show how comparatively frequent blindness to red is.

8. A case probably as well marked as T. R.'s, occurs in the person of a young clerical student in Glasgow, whom I shall call R. M. T. I have been disappointed in seeing him, but Mr Peter Stevenson, philosophical instrument maker, Edinburgh, who knows him intimately, ascertained the following fact, which is sufficiently decisive in reference to his vision.

He himself and his friends had long been aware that he was to some extent colour-blind, and by way of testing this, he was asked by Mr Stevenson, when recently in Edinburgh, to tell him the colour of a web of children's handkerchiefs hanging at a shop-door, distant in a straight line, about forty feet from the window where he was sitting.

The handkerchiefs in question were white, with rude designs and letters printed on them from copperplates in crimson ink, so that at a little distance they appeared pretty uniformly red. R. M. T. at once pronounced them to be "black like the print of a book;" and as the same designs are as frequently printed in black as red, an eye disposed to confound these colours, and more familiar with the former as occurring in engravings, would be put off its guard by the character of the lettering and designs presented to it. I have seen one of the handkerchiefs, which is of a bright, full crimson colour, but I do not know the peculiarities of R. M. T.'s colour-blindness. He is a student at Glasgow College, and Professor William Thomson has kindly engaged to test his colour-vision by the prismatic solar spectrum, so that further information may be given in the sequel concerning his case.

9. My friend, Mr John Crombie Brown, is acquainted with a party S. N. (known also to Alexander Christie, Esq.,A.R.S.A.), who has a fine eye for form and outline, but is markedly colourblind. In early life he was apprenticed to an upholsterer, and on one occasion being sent for black cloth to cover a coffin, he brought scarlet.

Other cases less fully examined have been reported to me by trustworthy parties.

10. Dr David Skae informs me of a young medical man, formerly an assistant in the Morningside Asylum, who was frequently compelled to appeal to others to decide for him, before sealing a letter, which was red and which black sealing-wax. Mr Walker, the eyesurgeon, also knew this gentleman, and recalls the fact of his mistaking red and black chalks for each other, when engaged in crayondrawing. He is at present in China, but has been applied to for the particulars of his case.

11. Mr R. S. Grieve, the large carpet-maker, George Street,

Edinburgh, tells me that he has often heard his father speak of a weaver in his employment, who, besides matching red with green, frequently matched scarlet with black.

who

12. To these cases I may add that of the Countess of D., enumerates together as colours she cannot confidently pronounce upon, "red, green, black, brown, and lilac." (Ante vol. xlvii. p. 504.) After encountering, without specially seeking for them, so many examples of the confusion of red with black, I thought it exceedingly unlikely that previous investigators of colour-blindness should not have met with cases of it; and on searching, it appeared that they had.

Thus Mr Harvey has recorded the case of a tailor in Plymouth who was otherwise colour-blind, and to whom black appeared "generally green, in particular cases crimson." A purplish red flower, the great snap-dragon (antirrhinum majus) he pronounced to be black, and "a very good match for my [Mr Harvey's] black coat." His master stated, that "being desired to repair an article of dress that required black silk, he employed crimson; and a similar mistake occurred on two other occasions."

"On another occasion, when a young gentleman's dark blue coat was brought to him for immediate repair, the mother was surprised to find the elbow of the coat repaired with crimson.' In connection with this last mistake, Mr Harvey quotes a case recorded by Dr Nicholls in the Medico-Chirurgical Transactions, where an officer in the navy "purchased a blue uniform coat and waistcoat, with red breeches to match." Here probably, as was the case with Mr Harvey's example, dark blue was undistinguishable from black, and the latter would have been confounded with red also.

Dr Colquhoun of Glasgow has described the case of a gardener in Clydesdale, who was originally a weaver, but gave up that trade, "because he confounded the red, black, green, and purple threads."? It is further stated in reference to this person, that "he confounds red with lilac, rose, brown, black, white, although he perceives the difference of the light tints and dark tints;" and that "in bright candlelight he cannot specify the shades of violet or brown, nor those of black, which he takes for brown, red, green, or black." In other respects his case was an extreme one.

I finally turned to Dalton's account of his own case, and that of his fellows, and at first it appeared that he had distinctly ascertained that he did not confound red with black, as I have already illustrated, by a quotation from his paper. Sir John Herschel and Sir David Brewster also, who both paid much attention to Dalton's case, have expressed their conviction that he saw as long a spectrum as others did, but that the red extremity appeared to him yellow. He should, of course, have seen a shorter spectrum than others, had red ap1 Trans. R S. E., vol. x. 1824, pp. 255–269.

Glasgow Medical Journal, vol. ii. p. 12., 1829, quoted by Wartmann. Scientific Memoirs, 1846, p. 168.

peared black to him; and no one can avoid concurring in the conclusion of the great opticians named above, that Dalton did not habitually fail to perceive the less refrangible end of the spectrum, although it did not appear to him red. Herschel, accordingly, in addressing Dalton, says: "It is clear to me that you, and all others so affected, perceive as light every ray which others do. The retina is excited by every ray which reaches it." And again,"It seems to me that we [the normal-eyed] have three primary sensations where you have only two. We refer or can refer in imagination all colours to three,-yellow, red, and blue. All other colours we think we perceive to be mixtures of these, and can produce them by actual mixture of powders of these hues, whereas we cannot produce these by any mixtures of others. Now, to eyes of your kind, it seems to me that all your tints are referable to two." A similar conviction is stated by Herschel, in his treatise on light in reference to the colour-blind as a class:-"All the prismatic rays have the power of exciting and affecting them with the sensation of light, and producing distinct vision, so that the defect arises from no insensibility of the retina to rays of any particular refrangibility."2

Sir David Brewster thus writes:-"In all those cases [of colour blindness] which have been carefully studied, at least in three of them in which I have had the advantage of making personal observations, namely, those of Mr Troughton, Mr Dalton, and Mr Liston, the eye is capable of seeing the whole of the prismatic spectrum, the red space appearing to be yellow. If the red space consisted of homogeneous or simple red rays, we should be led to infer that the eyes in question were not insensible to red light, but were merely incapable of discriminating between the impressions of red and yellow light. I have lately shown, however, that the prismatic spectrum consists of three equal and coincident spectra of red, yellow, and blue light, and consequently, that much yellow and a small portion of blue light exist in the red space;-and hence it follows that those eyes which see only two colours, viz., yellow and blue, in the spectrum, are really insensible to the red light of the spectrum, and see only the yellow with the small portion of blue with which the red is mixed. The faintness of the yellow light which is thus seen in the red space, confirms the opinion that the retina has not appreciated the influence of the simple red rays."

A reference to Dalton's own account of the appearance which the solar spectrum presented to his eyes, will show the compatibility of those conclusions with what I have now to urge. Dalton writes

The quotations are from a letter as yet unpublished, but which will appear in the forthcoming life of Dalton, by Dr W. C. Henry, by whom I have been favoured with a perusal of it.

2 Enclyc. Metrop. Article Light, p. 434.

3 Letters on Natural Magic. 1832. P. 31.

NEW SERIES.-NO. LII. APRIL 1854.

2 s

thus: "I found that persons in general distinguish six kinds of colour in the solar image, namely, red, orange, yellow, green, blue, and purple. Newton, indeed, divides the purple into indigo and violet; but the difference between him and others is merely nominal. To me it is quite otherwise. I see only two, or at most three, distinctions. These I should call yellow and blue, or yellow, blue, and purple. My yellow comprehends the red, orange, yellow, and green of others; and my blue and purple coincide with theirs." Assuredly, this passage appears unhesitatingly to assert, that to its writer the red end of the spectrum appeared yellow; and the fact that Dalton permitted Herschel and Brewster to refer during his lifetime to him as having this impression of the solar image, seems decisive of the matter, especially when it is taken in connection with the fact that the great chemist had anticipated the possibility of red appearing black to him, and had decided by looking at vermilion that it did not so appear. It must be remembered, however, that there is no common language between the colour-blind and the colour-seeing; that Dalton gave in only a silent and negative adhesion to the opinions which I have quoted; and that vermilion, besides that it is not a pure red, is a colour so intense, that although it did not appear black, other reds might. And that other kinds of red than vermilion did appear black to Dalton, is shown by his own account. After the passage which I have quoted, as descriptive of his impression of the spectrum, he continues as follows:-"That part of the image which others call red, appears to me little more than a shade or defect of light; after that the orange, yellow, and green seem one colour, which descends pretty uniformly from an intense to a rare yellow, making what I should call different shades of yellow."" The language here is very precise. The red is not spoken of as appearing yellow, or any other positive colour; but as appearing defectively illuminated or dark, i. e., more or less black; whilst the orange, green, and yellow are referred to as different gradations of one positive colour, namely, yellow.

It further appears that, in looking at coloured objects, Dalton was not liable to confound red with yellow, as he certainly should have done if these colours had appeared to his eye identical with each other. Thus, under the head of orange and yellow, as seen both by daylight and candlelight, he writes: "I do not find that I differ materially from other persons in reference to these colours. I have sometimes seen persons hesitate whether a thing was white or yellow by candlelight, when to me there was no doubt at all." And under red as seen by daylight, he states, as already mentioned, that crimson and pink generally appeared blue, and scarlet was confounded with

green.

Mem. Lit. and Phil. Soc. Manchester, 1798. P. 31.

2 Op. et loc. lit.

* Ibid. p. 34.

By artificial light it was otherwise; then crimson and pink became

Moreover, he tells us,-" All crimsons appear to me to consist chiefly of dark blue; but many of them seem to have a strong tinge of dark brown. I have seen specimens of crimson, claret, and mud which were very nearly alike. Crimson has a grave appearance, being the reverse of every showy and splendid colour. Woollen yarn, dyed crimson, or dark blue is the same to me." Again:-"The colour of a florid complexion appears to me that of a dull, opaque, blackish blue upon a white ground. A solution of sulphate of iron in the tincture of galls (that is, dilute black ink) upon white paper, gives a colour much resembling that of a florid complexion. It has no resemblance of the colour of blood." Again:-"Stockings spotted with blood or with dirt would scarcely be distinguishable." Lastly:" By day some reds are the least showy imaginable; I should call them dark drabs."

It thus appears, that as Dalton saw the red end of the spectrum dark or darkish, so certain red objects showed to his eye as dark blue, dark brown, dark drab, mud-coloured, dirt-coloured, or even like ink. The most famous example of colour-blindness, therefore, should seem, although he did not fully realize the fact himself, to have been in certain circumstances blind to red.

(To be continued.)

ARTICLE IV.-Enormous Growth from the Posterior Lip of the Os Uteri removed by Operation. By E. R. BICKERSTETH, Surgeon, Liverpool.

Margaret Helpin, æt. 39, a poor woman, in a very weak and exhausted condition, and of an exceedingly exsanguine appearance, applied to me in the middle of June last for a constant flooding, which had continued with hardly any interruption for eight years. She was the mother of several childrenthe last, eight years ago, was delivered by craniotomy in the Rotunda Hospital, Dublin, on account of a "tumour of the womb" which prevented the natural birth of the child. After this period she had a constant bloody discharge, and at times profuse hemorrhage, from the womb. She suffered from all the severe symptoms of long continued loss of blood, extreme weakness, frequent loss of sight, palpitation, dyspnoea, and occasional syncope. She had slight pain at the lower part of the back, and complained of weight and fulness in the pelvis ; also of a tumour which protruded between the vulvæ after standing for a short time. Her bowels were habitually confined and defecation very difficult.

On examination I found the vagina filled by a firm growth of fibrous consistence. It was of a conical form, the base being uppermost, and apparently continuous with the posterior lip of the cervix uteri, while the apex protruded slightly between the labia. The anterior lip very thin and almost membranous was felt on the front surface of the tumour as high as the finger could reach.

yellowish red or reddish yellow, and red and scarlet appeared much more vivid and superb than by day. In keeping with this, Dalton states, that in the prismatic image of a candle-flame, "the red extremity of the image appears more vivid than that of the solar image."