the musculo-cutaneous nerve from the outer cord. In the movements of the wrist and fingers the fifth and sixth nerves appear to co-operate, and those of the fingers are chiefly due to the sixth. The supinators and extensors of the wrist, fingers, and thumb get their nerves from the musculo-spiral or its interosseous branch. To resume, the fifth and sixth cervical nerves raise the shoulder, flex the forearm, and extend the wrist. The nervous energy passes from them along the upper trunk and outer cord of the brachial plexus to the flexors of the forearm, while the impulses to raise the shoulder, rotate the humerus, and extend the wrist and fingers travel chiefly through the posterior cord by the musculo-spiral nerve and its interosseous branch to the extensors of the wrist and digits. From the fifth and sixth cervical nerves we make a jump to the first dorsal, which has an exactly opposite action. The movements it produces are that the hand closes firmly upon the apple, the wrist is twisted round into the prone position and flexed to the ulnar side. The forearm is extended, and the upper arm is retracted in the manner required to pull the apple from the tree. In these movements, if you put your hand upon your chest, you will find that the pectoral muscles are largely engaged, and they receive their nerves partly from the internal cord of the brachial plexus. Flexion to the ulnar side is produced by the ulnar nerve, and the dragging of the arm down is effected by the subscapular, teres major, and latissimus dorsi muscles, which are supplied by the subscapular nerves, and the triceps by which the arm is extended gets its nerve supply from the musculo-spiral. But these movements, especially if executed forcibly, as they would be if the apple were firmly attached, would bring the hand below the level of the mouth, and the prone position would keep the apple away.

We must now go back to the sixth cervical nerve, which we find will rectify this action, for it raises the arm inward and upward with the forearm flexed, so as to bring the hand to the mouth, supinated, and with the wrist and basal phalanges extended, so as to present the apple comfortably for eating. In effecting this movement the nervous impulses travel by the posterior thoracic, circumflex, musculo-cutaneous, musculo-spiral, and median nerves to the serratus magnus, deltoid, biceps, brachialis anticus, supinator longus, and extensors of the wrist and basal phalanges. The position of Adam's left hand in Raphael's picture shows this action in its middle stage, before it has carried the hand to the mouth. The few last phalanges of his fingers are flexed, and we may suppose that the flexion is effected by means of the median nerve, but it is just possible that their flexion may be due to mechanical pulling on the tendons by the extension of the wrist and basal phalanges just as the hand is opened in the well-known

schoolboy trick by bending the wrist forcibly inward, and thus mechanically stretching the extensor tendons of the fingers. In this picture the action of the serratus magnus muscle in drawing

FIG. 15. THE FALL OF MAN. (After Raphael's picture in the Loggia of the Vatican, Rome.) The position of Eve's left arm illustrates the action of the fifth cervical nerve, and that of her left hand the commencement of action of the first dorsal nerve. The position of Adam's left arm shows the action of the sixth cervical. The action of the hallux is well shown in Eve's right and Adam's left foot.

forward the shoulder and rotating the scapula so as to raise the shoulder is well seen, and the action of the muscle appears almost exaggerated. We have already found that it gets a branch from

the fifth nerve as well as from the sixth. We may fairly suppose that the branch from the fifth is the channel for the impulses which cause the muscles to act as an inspiratory muscle when raising the arm to pluck the apple, while that from the sixth serves to excite the muscle to pull the shoulder forward. Now, here we have got, apparently, the movements required for plucking the apple and conveying it to the mouth, and yet we have got two nerves which seem superfluous-the seventh and eighth cervical. We may suppose the seventh to be brought into play later on, when the first pair recognized their nakedness, for its action in the monkey is to bring the hand over the pubis in the position of Eve's, as represented by Raphael in the Expulsion from Paradise (Fig. 14). We can not in this scheme find a place for the eighth nerve in the entirety of its action, as observed in monkeys, but the first part of the movement which it produces may be used in throwing away the refuse of food.

The mere fact that I have been unable to work this last nerve properly into this scheme shows you how imperfect it is, yet I trust that, as an attempt to hang together the facts-anatomical and physiological-it may not be without service as an aid to your memories, and still more as an inducement to you to find out the true relationships of the different parts of the body.

PROF. G. F. WRIGHT AND HIS CRITICS.*

BY PROF. E. W. CLAYPOLE, B. A., D. Sc. (LOND.), F. G. SS. L. E. And Å.,

FOR

AKRON, OHIO.

OR more than twenty years a controversy on the antiquity of man has prevailed in the scientific world. This controversy is still far from decision. The origin of the human family is veiled in obscurity, and all efforts to discover our primeval ancestor have hitherto failed. The gloom and darkness enshrouding the past are not yet sufficiently dispelled by the light of science to reveal prehistoric man in his early stages.

The geologist and the archæologist have been chiefly engaged in the search. They have followed the trail of man to some distance and can tell us something about him within narrow limits. But beyond these their efforts have met with little success. At this point it seems as if some huge effacing hand had swept across the field and blotted out almost every trace of his existence.

And this is no mere imagination. A huge effacing hand has

*Man and the Glacial Period. By G. F. Wright. International Scientific Series. D. Appleton & Co.

swept across the field and wiped out the records written as with an iron pen on the rocks, and has engraven in their stead a palimpsest of its own. The Ice age is now a familiar topic, and its massive ice-sheet a reality to all. The continental glaciers which covered a great part of North America and Europe with ice thousands of feet thick, and enduring for thousands of years, literally swept from the face of the country the monuments of preceding life, leaving in their place its own memorials which the geologist is now learning to interpret.

Here is the unexpected barrier which meets the archæologist and the geologist in their investigations. They can follow the trail of man back into the Pleistocene era almost or quite to the edge of the ice. There it either becomes exceedingly faint or is lost altogether. In the tangled maze of glacial history the previous confusion is worse confounded, and the thin thread of evidence for man's existence is broken or lost.

The nature and date of the Glacial era and man's relation to it thus become important problems in the main issue, and it is these with which Prof. Wright's book deals. To some geologists the Ice age was single, to others it appears to have been double, triple, or even more complex. Some believe that man was contemporary with the later and even with the earlier stages of the era. Space will not allow us here to do more than mention these divergences of opinion, but so much was necessary in order to understand the scope of the work.

The appearance of Prof. Wright's little book has been the signal for a renewal of the controversy with fresh energy, not to say with acrimony, yet in it the ordinary reader would scarcely find any cause for commotion. It is for the most part merely a condensation of the same writer's larger work on the Ice Age in North America. Its aim is to lay before the general reader a short sketch of the present state of our knowledge of the Glacial era, and to briefly state the evidence bearing on man's existence during it or any part of it. The book is not sensational; it contains little or nothing that is new; it publishes no startling facts; it propounds no novel or strange theories, scientific or unscientific; it is simply, as it professes, a summary view over the field of glacial geology.

The author is well known to geologists by his share in the epoch-making work of tracing the southern limit of the ice-sheet across the North American continent. This was accomplished by him in connection with Lewis, Upham, Smock, Chamberlin, Cook, Leverett, etc., and, as far as the western Illinois State line, may now be considered definitely known. In this great work Prof. Wright may fairly claim a place among the first, having commenced his studies on the drift hills of Andover,

Mass., as early as 1876, when his first paper was read before the Boston Society of Natural History. Largely through him the late Prof. H. Carvill Lewis was brought into the work, and our author's studies on the Muir Glacier in Alaska gave us most of our early knowledge of a region previously almost a terra incognita to science.

Qualifications thus won by hard work in the field secure for the author, Prof. Wright, no mean place among glacial geologists, and entitle him to at least respectful attention. It is therefore somewhat surprising to note the storm of criticism and even abuse with which the work has been assailed by certain geologists.

Far be it from us to deprecate criticism, even if severe. Equally far is it from the desire of the author. But we feel justified in the name of science in entering a protest, and a strong one, against the style and manner of the articles which have appeared in condemnation of the work and in denunciation of the writer.

In thus protesting against so unusual and apparently concerted an attack we do not wish in any way to defend the author from so much criticism as is just and courteous. The book is far from perfect. We can not acquit the writer of apparent haste in its completion. Besides inaccurate expressions there are in some places insufficient statements of the divergences of opinion. Many of these have been already pointed out, and have received all the blame that is due, and in no measured terms. The title, for instance, should have run, The Glacial Era and Man, for of its ten chapters only one is closely connected with human history. It is scarcely correct to write of the great interlobate moraines as medial (page 100). We presume that our author means that their material was carried on the ice during its flow. This was in great part true, but they did not exist as medial moraines at any time, and were only formed at the melting end of the ice-sheet. Nor do we think that any evidence worth consideration can be adduced in support of the supposition of a great southern subsidence to explain the origin of the loess in the Mississippi Valley. We think that Prof. Wright should have recognized the fact that northern drift had been reported from Kentucky many years before his visit (page 212), and the expression "I have traced the limit of southern bowlders for thousands of miles across the country" is certainly unfortunate. It is, perhaps, literally true in the sense intended, but it is liable to misconstruction, and has been misconstrued. We might also object to his use of the word "preglacial." In this, however, he has many companions among geological writers.

We may further add that his explanation of the relation of the névé to the glacier has been assailed with justice, and is quite indefensible. There is, however, little occasion here to expose