own efforts, Mrs. Whiting has devoted considerable time and attention in preparation of material for courses and in instructing individual students, thus relieving other members of the department.

My "Program for Teaching and Research in Biological Science at the University of Maine," which was submitted to you after President Little's departure, was worked out with much care and approved by several eminent biologists at the university. It was, however, negatived by the administration in points essential both to efficient teaching and to research, despite the fact that the present budget allowance was ample to cover all expenses involved.

I assure you that I am leaving Maine with no feeling of resentment, but with the hope that a more constructive policy will be pursued in the future.

Very truly yours,

(Signed) P. W. WHITING

SCIENTIFIC BOOKS

Textbook of Comparative Physiology. By CHARLES GARDNER ROGERS. McGraw-Hill Book Co., New York. 1927. List price, $5.50.

To state that Professor Rogers's book is new and different from others tells little; yet even this feeble remark may attract attention to the work among the books of the year. The present writer is not a physiologist, but he feels moved to say something about the book for the benefit of his non-physiological brethren. Professional physiologists will soon be familiar with it; zoologists and botanists working in other fields need to have it brought to their notice.

A few of the chapter headings may be listed: II. Solutions, III. Diffusions and Osmosis, V. Properties of Protoplasm, VII. General Phenomena of Life, X. Blood as an Oxygen Carrier, XIII. Circulatory Mechanisms, XVIII. Catalytic Actions of Animals, XXII. Nutrition of Different Animal Groups, XXVI. Physiology of Movement. These rather familiar titles, most of which are found in all physiologies, suggest the general scope of the work and yet they do not give any intimation of the freshness of treatment and the breadth of outlook which our author brings to us. In his hands, physiology becomes functional biology, the real science of life.

Dr. Rogers compassionately spares us the multitude of algebraic formulae and soul-corrupting graphs now so popular. He is teaching physiology, not mathematics, physics and chemistry. He gives clear pictures of life processes in general and offers a wealth of information about the physiology of invertebrates not obtainable in our usual books of reference. He presents his material in logical and interesting form with no apparent bias for pet theories. If an outsider might presume a suggestion, it would

Ice Ages, Recent and Ancient. By A. P. COLEMAN. New York: The Macmillan Co., 1926. pp. 296, 51 figs., 8 maps.

IT is the stroke of the master pen. Only mastery could produce so complete, frank, simple and obviously trustworthy an account of the Ice Ages of the earth. Many accounts of personal experience enliven the style of the book. As an introduction to the work of ancient glaciers, the activities of living glaciers are sketched with a few well-chosen examples. The Pleistocene glaciation is treated only briefly, since "the work is not intended to take up the Pleistocene in great detail, but rather to outline its extent, to describe its mode of operation and to study particularly such features as will throw light on more ancient and therefore less completely recorded glaciations." The drift, the extent, the centers of radiation and the interglacial periods are discussed both for North America and abroad. One interesting point in North America is that the Cordilleran sheet was formed first and was followed in succession by the Keewatin and then the Labradorian sheets. It is inferred by the reviewer that this applies to the last of the Pleistocene sheets. It would be of great interest to know whether this succession holds for the earlier of the Pleistocene invasions. Doubtless data are not available to answer this question, for the author makes no mention of it. Four interglacial periods are recognized near the drift-margin in North America, while at least one is distinguished in Canada near Toronto and Moose River. Likewise three warm interglacial periods are accepted in the Alps and in Denmark, while studies of the interglacial climates have led to the conclusion that the ice in Europe, as well as in North America, was completely removed at least once during the Pleistocene.

Ancient ice ages are beautifully described. Eocene and Jurassic tillites in North America are discussed. In all the periods of the Paleozoic era, glaciation is either strongly inferred or is proved. Of these the world-wide Permo-Carboniferous glaciation, the greatest in the history of the earth, receives its due consideration. Chapters on the Talchir tillite of India, the Dwyka of South Africa, the Squantum of North America and the tillites and interglacial deposits of

South America and Australia are very impressive. They leave no doubt in the reader's mind of the magnitude and certainty of the refrigeration. Continental ice sheets of Silurian age are known in Alaska. The Varanger Fiord tillites of northern Norway have been recently correlated with the Ordovician. Widespread Ordovician glacial conglomerate is also recognized in Gaspé. Early Cambrian or late pre-Cambrian tillites are described from the Yangtzi Canyon in China, from southern Norway, from several places in North America, from Africa and from Australia, placing this ice age as equal in magnitude to that of the Pleistocene.

The widespread Gowganda tillite of Huronian age in Canada is convincingly described as of glacial origin. And beds of similar age, probably of glacial origin, are cited from several other parts of the world. Conglomerates strikingly like tillites are discussed from the Timiskamian and Keewatin rocks of Canada, though metamorphism has rendered their sure reference to glacial origin uncertain.

The effects of glacial periods on both plants and animals, treated rather fully, makes a very suggestive contribution to the study of organic evolution.

Defects in all existing theories of the cause of ice ages are pointed out. But the author confesses he is unable to propose something better. In his opinion the solution must come from general and local causes in a combination of astronomic, geologic and atmospheric conditions.

Photographs are numerous and in general very good, though many of them lack a scale. The book is of great importance not only to the glacial geologist, but to the historical geologist, the paleontologist and the paleobotanist as well.

UNIVERSITY OF CHICAGO

PAUL MACCLINTOCK

SPECIAL ARTICLES

THE NATURE OF THE "INORGANIC
PHOSPHATE" IN VOLUNTARY
MUSCLE

SOME months ago we1 described a colorimetric phosphate method, the special feature of which is the use of a very active agent (aminonaphtholsulfonic acid) for converting the phosphomolybdic acid to its blue reduction product. When we first made use of this method for the determination of inorganic phosphate in protein-free muscle filtrates, shortly after the details had been worked out, we found a marked delay in color production. The time required to reach a constant reading was about thirty minutes, whereas 1 C. H. Fiske and Y. Subbarow, J. Biol. Chem., Vol. 66 (375)-1925.

ordinarily the full color (relative to the standard) has developed within four minutes or less. This peculiar behavior appeared to indicate that muscle contains either some substance capable of retarding the color reaction or else a very unstable (presumably organic) compound which liberates o-phosphoric acid while the color is developing. While the course of the color development in muscle filtrates turned out to be quite different from anything which we had seen in testing out the method in the presence of known interfering substances, it is impossible to rely on this point as a means of distinguishing between the two alternatives. Ferric salts, for example, also behave in a way that is unique. A mixture of inorganic phosphate and ferric chloride certainly does not contain a highly unstable organic phosphorus compound, and the delayed

color reaction found with muscle filtrates therefore does not constitute conclusive proof of the existence of such a substance in the muscles.

Further study of the course of color development nevertheless did bring out some interesting and suggestive points, notably the fact that the delay is hardly any more pronounced with 10 cc of muscle filtrate, for example, than with 5 cc or less. Every interfering substance which we investigated in the course of our work on the phosphate method, on the other hand, shows a much more marked effect when the phosphorus content of the sample is increased. Although these facts have been in our possession now for more than a year, we have until this time refrained from placing them on record, inasmuch as the phenomena observed could not with any certainty be ascribed to the presence of an organic compound of phosphoric acid until the compound had been isolated, or at least until the organic radicle had been identified. Both these things have now been done, although the isolated substance has not yet been obtained in the pure state, and the outcome appears likely to throw light on a field of biochemistry never before suspected of being in any way related to phosphoric acid.

Muscle filtrates from which all the inorganic phosphate has been removed (by precipitation with barium, silver, etc.), as well as material which has been still further purified, show the same delay in the production of the color. These facts, together with the knowledge that the delayed reaction really is associated with the hydrolysis of an organic compound of phosphoric acid, give real significance to the quantitative data which we have meanwhile been accumulating. Some of these data will now be presented before we proceed to a discussion of the nature of the substance.

The method which we have used for the determination of this unstable form of phosphorus (which we shall for the present designate as "labile phosphorus")

differs in no respect from our regular phosphate method, except that readings are taken at brief intervals (every minute, beginning with the third, until the unstable substance is about half hydrolyzed, and thereafter every few minutes until no further change occurs). The growth in color intensity for the first few minutes is practically linear, and the concentration of inorganic phosphate is found by extrapolating back to zero time. The sum of the inorganic and the "labile" phosphorus is calculated from the final reading, and the amount of "labile phosphorus" found by difference. From control analyses of solutions of the purified organic compound, with and without the addition of known amounts of inorganic phosphate, we believe that the results are accurate within 1 or 2 mg of phosphorus per 100 gm of muscle.

The principal results which we have obtained by this method of analysis are as follows: (1) The normal resting voluntary muscle of the cat shows generally about 60 to 75 mg of "labile phosphorus" per 100 gm if removed with the greatest possible care and at once cooled to 0° C. or below. (The further preparation of the material for analysis consists simply in precipitating the protein with ice-cold trichloroacetic acid, filtering and immediately neutralizing the filtrate with sodium hydroxide.) The true inorganic phosphorus under these conditions is only 20 to 25 mg, instead of the 80 to 100 mg, shown by other methods of analysis. (2) After prolonged electrical stimulation, the "labile phosphorus" usually falls to about 20 mg (in one instance to as little as 9 mg), while the inorganic phosphorus is correspondingly increased. (3) Stimulation with the blood supply shut off, in which case complete fatigue ensues, causes complete disappearance of the unstable compound, within the error of analysis. Merely shutting off the circulation for an equal length of time has little or no effect. (4) A period of rest after the muscle has been stimulated is accompanied by resynthesis of the organic compound. The maximum yield of "labile phosphorus" so far observed under these conditions is 46 mg per 100 gm of muscle. The inorganic phosphate, however, falls to the normal level, so in all probability either some of the phosphate has been discharged into the circulation, or else the water content of the muscle has increased.

The compound under consideration is a derivative of creatine. On a small scale we have succeeded in separating it from all other phosphoric acid compounds. On a sufficiently large scale to yield material enough for a complete analysis, the separation is not so readily accomplished by our present methods, and the best products that we have so far procured contain several per cent. of one or more other phosphorus compounds, since the full blue color can not be ob

tained unless the material is ashed. In spite of this contamination, the phosphate, creatine and base in two salts which have been prepared add up to about 85 per cent. of the weight of the entire substance, indicating the probable absence of a third component. The elementary analysis of amorphous products, unless they are of definitely established purity, proves very little. Our main evidence for the existence of "phosphocreatine" in muscle is of a quite different nature. In the first place, we have found that the "labile phosphorus" can be more or less completely separated by precipitation with a number of different reagents (six in all have been used to date), and that in each case there is precipitated with it one equivalent of creatine. One of these reagents (copper in slightly alkaline solution) has been applied to muscle filtrates prepared under various conditions, and the proportionality between creatine and "labile phosphorus" has never failed. A few typical illustrations of our experience with copper precipitation are given in the accompanying table. They serve to show that creatine and the labile form of phosphate are precipitated together, in equivalent proportions, whether the muscle was fresh and in the resting state or whether it had been subjected to manipulations which alter the concentration of the "labile phos

phorus." Thus, when the muscle is allowed to stand outside the body, the "labile phosphorus" content progressively diminishes at a fairly rapid rate (it is entirely gone in less than twenty minutes), and at the same rate creatine is set free, as indicated by its failure to be thrown down by copper. If the trichloroacetic acid filtrate prepared from a sample of fresh muscle is kept (unneutralized) for several hours, the "labile phosphorus" has completely disappeared, and the copper precipitate is then virtually free from creatine. The same parallelism holds for muscle which has been stimulated, showing that the liberation of inorganic phosphate during stimulation is associated with the conversion of the creatine to a form in which copper will not precipitate it. Finally, in case the muscle has been stimulated with the blood supply cut off-a procedure which, as stated, leads to the loss of all the "labile phosphorus"-and then permitted to recover, the reappearance of "labile phosphorus" is accompanied by the return of an equivalent quantity of creatine to the condition in which precipitation by copper does take place. Direct evidence for the synthesis of a creatine-phosphoric acid compound during recovery is thereby attained.

Quite aside from its obvious bearing on the mechanism of muscular contraction, the demonstration of "phosphocreatine" in muscle should go far towards providing an explanation for a number of matters which in the past have been obscure. Among these may be mentioned the passage of administered creatine into muscle in spite of the large quantity already there, and the striking difference between resting (living) muscle on one hand and fatigued or dead muscle on the other in their capacity for retaining both creatine and phosphate, as shown by perfusion and dialysis experiments.

BIOCHEMICAL LABORATORY,

HARVARD MEDICAL SCHOOL

CYRUS H. FISKE Y. SUBBAROW

ON THE UPPER LIMIT OF VIBRATIONAL FREQUENCY THAT CAN BE REC

OGNIZED BY TOUCH

In relation to experiments on the transmission of speech instrumentally to organs of touch in the skin and to end organs of the sense of vibration it is of more than ordinary interest to discover what is the upper limit of vibrational frequencies that can be felt through these senses.

Landlois (Lehrbuch d. Physiol. d. Menschen, 1880) states that vibrations of strings are recognizable at a frequency of 1552 a second. This is the highest figure that has been published hitherto.

Dr. V. O. Knudsen, of the Department of Physics of the University of California, reports in a paper that is about to be published that his subjects reached no higher than 1600 d.v. a second. The stimulus was furnished by an oscillator and was applied through a reed slapping near the tip of the subject's middle finger.

In my experiments the stimuli are the vowel qualities e, er, oo, o, ah and aw, spoken into a high-grade microphone. A modified 25 B (Western Electric) two tube amplifier is in circuit. An electrical filter has been introduced also, and a five unit receiver or teletactor. Each of these instruments has been made for my use by the Bell Telephone Laboratories. The filter analyzes the speech frequencies into five bands: 0-250; 250-500; 500-1000; 1000-2000 and 2000 plus vibrations a second. Each band is led into one unit in the receiver and into no other. In the course of the experiments that are reported here connections have been broken so as to eliminate all but the highest band of frequencies-2000 d.v. and above.

When the vowel qualities already mentioned are pronounced into the microphone the subject feels the fifth reed that remains connected through the filter when it is in vibration. The figures below indicate the degree of the subject's accuracy of detection. He reported "yes" when he felt a vibration; otherwise he was silent. The stimulus is received through the finger nail or through the skin-preferably the former.

was going on, was thirty-five feet from the subjects, behind two closed doors and standing upon a pile of papers and magazines to damp vibrations that may otherwise be assumed to reach the subject through the floor from the experimenter's body.

When connection was broken between the microphone and the receiver and the experimenter continued to pronounce as usual the subjects gave no sign of knowledge that anything was going on.

What the subjects felt may have been far above a frequency of 2000 a second. It was at least as high as that. High frequencies in the male voice run up as follows: e, 2987; oo, 3700; er, 3050; o, 3475; ah, 3683; aw, 3612, (Crandall, Sounds of Speech; The Bell System Technical Journal, IV, 4). In fact these figures are next above 1965 in Crandall's table. It is highly probable that our subjects are sensing vibrations that occur with a frequency approximating 3000 a second.

ROBERT H. GAULT

VIBRO-TACTILE RESEARCH LABORATORY, NORTHAMPTON, MASS.

POSSIBLE SOURCES OF SOME BOULDERS IN THE GLACIAL DRIFT OF MISSOURI THE writer realizes that it is not an entirely safe procedure to identify a rock specimen, found in glacial drift, as having come from a certain locality, by comparing the megascopic characteristics of the specimen with the recorded descriptions of rocks from various localities. With a full realization of this uncertainty, the writer has endeavored to locate the original sources of some of the glacial boulders in the vicinity of Columbia, Missouri.

A large variety of rocks has been identified in the glacial drift in the vicinity of Columbia. These rocks include granites of various colors and varying coarseness of texture, dolerites, hornblendites, basalts, gneisses, both hornblende and mica schists, anorthosites, quartzites of various colors, conglomerates and a quartzose-looking rock. For most of these rocks, the writer has been unable to locate successfully their original sources. The last four rocks above mentioned are the ones about which the writer wishes to make a few remarks.

Anorthosite is not a common rock, being known to occur in relatively few places in North America. It is known to occur in the following localities: Adirondack Mountains, in Wyoming, several places in Canada, such as in the region of the headwaters of the Saguenay River, and north of Montreal, in the Lake Superior region in localities as Carlton Peak, Shingle Cove and other places. The writer believes that the anorthosite found in the glacial drift in the area under consideration came from the anorthosite locali

ties along the west shore of Lake Superior. This is the only probable locality from which the anorthosite Icould have come.

The quartzites in the drift are largely the Sioux quartzite, which is the hard, red quartzite found in Minnesota, Iowa and South Dakota.

The conglomerate, which is of much interest locally, is a jasper conglomerate. The jasper pebbles are the red-banded and black-banded varieties. These pebbles, along with quartz pebbles, are firmly cemented with a siliceous cement. The conglomerate closely resembles a portion of the Ogishke conglomerate, of Huronian age, found in the Vermilion Range of Minnesota.

The "quartzose-looking" rock is a dark red, finegrained rock containing sandy granules of red jasper. Grout,1 to whom a sample was sent, says of it, in part-"I have never seen (it) in place anywhere except on the Mesabi range, as a part of the iron-bearing formation." It agrees with the description of the ferruginous chert which makes up a part of the ironbearing formation in the Mesabi range.

The direction of movement of these rocks, if their original localities as stated be granted, was therefore from the north directly to the south, in almost a north-south line. The post-glacial movement, due to running water, is believed to be slight.

In the vicinity of Marysville, Nodaway County, Mo., and at Green City, Sullivan County, Mo., there have been found several pieces of native copper in the glacial till,2 the age of the till being unknown to the writer. According to W. A. Tarr, one of the pieces of copper weighed about twelve pounds. The only logical locality from whence this copper could have come is the copper country of Upper Michigan.

Upham3 states, "In Lucas County, of southern Iowa, a mass of drift copper weighing more than thirty pounds undoubtedly was borne by the currents of the ice-sheet about six hundred miles, from the present copper-mining region south of Lake Superior or from Isle Royal, first southwestward and later southward through eastern and southern Minnesota, passing west of the Wisconsin driftless area. journey probably was accomplished mostly during Nebraskan time."

Its