same, and his dead stop and refusal to name them, coupled with his ready reception of a colour the opposite of yellow as purple, are exactly the features of colour-blindness as I have constantly seen it in those who confound red with green.1

The other artillery soldier, on being shown a slate-coloured paper, pronounced it to be yellow, but on this name being challenged, described the colour correctly. On asking him why he had previously named it differently, he replied, that on first looking at it it had appeared to him yellow. This perhaps was simply a case, where a fixed gaze on one colour brought up its complementary colour, according to the well-known law of such alternations. But even regarded as such, it is curious, for the man had done no more than glance at the paper when he named it, whereas a normal eye must look long and steadily at a colour to bring into view its complementary; and, moreover, in this case the complementary colour alone was seen without a previous perception of its primary.

Altogether, therefore, both of the cases detailed are probably entitled to rank as examples of a slight or incipient manifestation of a rare variety of colour-blindness, of which more marked cases will be found if sought for.

The confusion of red with green, which first largely attracted attention to colour-blindness, extends, though not equally, to all the shades of both colours; and each is also liable to confusion with other colours, so that the great majority of cases of chromato-pseudopsis group themselves under red or green, or both. I shall first

consider the confusion of these colours with each other.

Red, without any tinge of yellow on the one hand, or of blue on the other, is for most persons rather an ideal than a real colour, and there is a very marked difference in the sensitiveness of eyes reputed normal, as to the distinction between red and crimson, red and scarlet, and crimson and scarlet: but on this point it is needless to

Above 700 soldiers in the Edinburgh garrison were examined as to the quality of their vision of colours, but as they were purposely left in ignorance of the object of the examination, many of them supposed that Mr Dun, who assisted me, and myself were government or military inspectors, and that dismissal from her Majesty's service might follow the discovery of any defect in their eyesight. We did our best to set the men at their ease, but several of them were a good deal discomposed, and a few were somewhat sulky. The particulars of this examination are given in another part of the paper.

2 This is curiously exemplified in the apparent total inability of medical men to determine whether arterial blood is scarlet or crimson. The poets and painters appear to have unanimously decided that it is crimson; whilst the Spanish grandee prides himself on his blood being blue. In reality, blood shows all these colours. Seen through a vein it appears blue; drawn from it, it appears purple; as it undergoes oxygenation it becomes crimson and then red. When coagulation commences, the yellow colour of the serum shades the red into scarlet, and when allowed to dry up, blood becomes brown. We should avoid a needless difficulty, if without affecting too great precision, we styled living arterial blood, neither crimson nor scarlet, but simply red.

NEW SERIES.—NO. XLIX. JANUARY 1854.

F

dwell at length, for all those colours are confounded with green. I wish, however, to notice, that as crimson by the addition of blue, passes insensibly into red-purple; and scarlet by the addition of red into orange, it is to be understood, unless otherwise stated, that by crimson and scarlet are signified always the redder, and generally the reddest shades of these.

No term includes a greater number of different shades of colour than GREEN, chiefly, no doubt, because nature presents to us on every side so great a mass of green, and so many tints of it. I cannot, accordingly, decide what colour exactly is signified by those subjects of colour-blindness,, who have communicated to me their cases in writing; but, in general, I intend by green, a mixture of yellow and blue, in which a normal eye sees no excess of either. Very great differences occur in the judgment of different persons as to the preponderance of one or other of its components in a green; and it would be convenient to have a standard shade for this abundant and important colour, such, for example, as the green which is complementary to pure red, i.e., a compound of all the blue and yellow in the solar spectrum. But very few are familiar with this green, and I must leave each normal-eyed reader to choose for himself a shade of this colour free from the least bluish or yellowish tinge.

It is scarcely necessary to particularize the cases on record in proof of the insensibility of colour-blind eyes to the difference between red and green by daylight. Dr K. and Dr Y. confound full red, scarlet, and crimson, with various shades of equally full and bright green. The former gentleman, as well as Mr T. and Admiral have independently referred to a red or scarlet cloak, coat, or jacket, as undistinguishable by them, from a hedge or the leaves of a tree. Lord V. thought a lady's green dress scarlet. Mr N.'s brother picked up a red-hot coal as " a green thing." Lady D., Dr E., and Mr Hughes, cannot tell the scarlet berries of the mountain ash from its leaves. Dr Bryce could not distinguish a scarlet geranium from its foliage. Dugald Stewart made the same mistake with cherries. Dalton held red sealing-wax to match with grass in colour. The tailor's foreman referred to, proposed to sew green tapes to a scarlet waistcoat. Dr Y. could not see a difference between the red and green railway signal glasses. And in addition to the cases described in the previous portions of this paper by me, I found in the Edinburgh garrison eleven soldiers, who put side by side as of the same colour, full scarlet and crimson wools, along with full and pale greens, and who identified red with green glass.

A question here arises, much more easily asked than answeredDo colour-blind persons of the class described, see red, but not green; or green, but not red; or do they see both, or neither? This question, or series of questions, will be variously answered, as, so far, it has been by different authorities, and probably demands a different answer in different cases. My own strong conviction, which is at variance with the opinion of some distinguished writers

on optics, is, that red and green are both visible in favourable circumstances to the majority of the subjects of chromato-pseudopsis.

I am led to this conclusion by two considerations:- 1. All the colour-blind persons whose vision I have formally tested, could in favourable circumstances occasionally distinguish red from green; and although always uncertain as to the difference between them, and easily shaken in their conclusion as to which was which, yet practically acted on their judgments, which were not always wrong.

2. I have stated, in reporting Mr Hughes' case (p. 391), that, "When asked to select, from a number of pieces of coloured glass, all the specimens which were red, the majority were rightly chosen, but two or three were green; and in the same way, when assorting greens, he placed a few reds among them." Struck by this fact, I watched narrowly the deportment of the colour-blind soldiers in the Edinburgh garrison, when asked to select reds from greens, and with great uniformity they acted thus:- From a heap of coloured wools, each was asked to select first the red skeins, and then the green, no notice being taken of the selection of individual skeins till eight or nine had been set aside as red, and as many as green. In all cases the majority of skeins were rightly chosen,-five or six, for example, in the so-called red bundle, were red, and two or three green; and vice versa in the so-called green bundle. It is impossible, I think, to avoid the conclusion that, to those who acted thus, the sensation of red, when felt in its full intensity, is distinct from the sensation of green; yet so slight was the difference to their eyes, that they would not unfrequently, on looking at the two bundles, transfer a red skein, as wrongly placed, from the red bundle to the green, or the opposite; and in no case, even when informed that certain of the skeins were in the wrong heap, did they succeed in a just assortment of them. Prolonged contemplation of the colours, indeed, seemed in all cases to make matters worse; and, in general, I have found that the colour-blind, when informed that they have made a mistake in selecting hues, become increasingly uncertain concerning them, and give up for the time attempting to distinguish between them.

It thus appears that red and green are both occasionally perceived in daylight by those who more commonly are blind to them, and that the majority of the colour-blind cannot be defined as possessors of "Dichromic Vision," in the strict sense of that term, although it is quite true that they are only certain regarding the two primary colours, blue and yellow.

In what has been stated, red and green are referred to as seen by sunlight; but it is a remarkable fact, which has not hitherto been sufficiently regarded, that, by gaslight or candlelight, the distinction between red and green, which to the colour-blind was so slight by daylight, becomes in many cases quite apparent. My attention was first directed to this matter by the statement of Mr N. (p. 496), that by.

candlelight crimson flowers, such as fuchsias, which by day had been lost among the leaves, stood out in contrast with the foliage, so that it was "then quite an enjoyment to look" at them.

On reading this, I recalled the account given of his colour-blindness by Mr D. (p. 336), that "the flowers of a scarlet geranium I cannot see distinctly by daylight; but by candlelight there is a marked contrast between them and the leaves."

Without any knowledge of Mr N.'s statement, Prof. Y. repeated (p. 499) his experience in nearly similar words, adding that he always delighted in going into a conservatory by candlelight, because all the purple and red flowers stood out in such brilliant contrast to the green leaves ;" and he further mentions that scarlet flowers then appear brighter than by daylight. Mr R., who proffered the account of his case, stated that," Sometimes I can see some reds and greens by lamplight" (p. 494), and in illustration of this mentioned the very striking fact, that a baize curtain which he bought as green by daylight, and which was then agreeable to his eyes, proved excessively painful by lamplight, and turned out to be "a very bright red."

Dr E., in answer to queries, reported his experience to be exactly similar. Dr Y. whom, by daylight, I had found to make the greatest mistakes between red and green, by gaslight made far fewer blunders (p. 493).

Lastly, Mr S. reports one of the colour-blind persons known to him as being in the practice of resorting to a room lighted with gas or candles, when he wished to tell the difference between scarlet and green, and crimson and blue. (P. 502.)

(To be continued.)

Part Second.

REVIEWS.

Lectures on Surgical Pathology, delivered at the Royal College of Surgeons of England. By JAMES PAGET, F.R.Š., lately Professor of Anatomy and Surgery to the College, etc. etc. 2 vols. 8vo. London, 1853.

DURING the period that Mr Paget held the Professorship of Anatomy and Surgery of the Royal College of Surgeons of England, he delivered an annual course of six or eight lectures to its fellows and members, in order to illustrate that portion of their museum which comprehends general pathology. These lectures extended and rendered more complete by the introduction of numerous facts and quotations, which time, or their inaptness for oral delivery then obliged

him to omit, are contained in the present volumes. Why they should be called on Surgical Pathology is not stated, nor, indeed, is it easy to find a reason why pathology any more than physiology, should be divided into medical, surgical, and obstetrical, unless their being taught by persons who practice different departments of the profession, be deemed a satisfactory one. It frequently happens that these subjects, such as healthy and morbid nutrition, inflammation, mortification, specific diseases, cancerous and tubercular formations, etc., are taught by physicians, yet it would be as injudicious in them to call these topics medical pathology, as it is in Mr Paget to denominate them surgical pathology. We trust our readers, therefore, will not be misled by the title of these volumes. They will be as useful to the physician and obstetrician as to the surgeon. They bear no especial reference to the art of surgery, but rather to that science on which every branch of the profession ought to be grounded.

With regard to the work itself, it is one of comprehensive aim, executed with a complete knowledge of the present state of pathology, together with a thorough acquaintance of the whole range of ancient and modern literature, domestic and foreign. It aspires not only to communicate and to generalise upon what is known, but to advance the boundaries of science by the acquisition of new facts, by the results of independent and original research, and by the careful, candid, and earnest endeavour of a mind qualified to investigate and able to interpret. Such a work ought, and we have no doubt will, exercise a powerful influence on the progress of pathology, and consequently on the practice of medicine and surgery. It should therefore be carefully studied by all our readers who desire to see the profession connected with a sound philosophy, and to exercise their art on a scientific basis.

Having said so much, we might here pause, satisfied that whatever objections might be made to this or that portion of Mr Paget's writings by the individual reader, his general opinion would coincide with our own. But it is exactly on account of its great merit as an exponent of facts, that we feel indisposed to allow that all the doctrines it contains should be considered as proven. On the contrary, many are far from being established, and several are in our opinion faulty. It is the more important to remember this, and to be somewhat guarded in admitting all the views of the author, because, we have no doubt, the work will justly be received as one of high authority. We shall endeavour to illustrate this by discussing with Mr Paget one or two points in which we differ, leaving our readers to judge whether he or ourselves be in error.

Most writers on inflammation have expressed the same idea as Mr Travers, when he observed" that a knowledge of the phenomena of inflammation, the laws by which it is governed in its course, and the relations which its several processes bear to each other, is the key-stone to medical and surgical science." To the truth of this statement we emphatically subscribe, and hence we deem it a duty