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Ciegiees tigen tee “ahs wa Wit ef rahe nreae rae ait - “ dy FAD, cP Ms wae es Sraaet S99 C954 ¥ Tatas Est Ay phair ee oor elgh ge Liptptelser : i bf rete: Fe Retspuaamea Bf ag hae? a2 eres nal i bead Meets, Reeves pacitee ee ~ ree cree Shad Savin aban fe a ste aie ara Rivets ra Fie Jiaehaterad totes { ae 2 Rte Pag aoe eee Sd ie Benes ees: nat ; ; ite tags Bee ae at Peet te int Lien ye Rk iselee eaenes) — ncnady 2 Naty tr me Me Lanes wy id Ter yy inditend: ioitinin we a el ike Hts ee ey eet rete aia ited vette ” oe este pokes eae fey See Atos , ae ts Aaa ee aa ene ete re ” ay ney ay hyd Sree teaed reer tH ies 43 asthenia peatatdel Reise " Sock tees ee} Soh Lee Py ore C4 ya itech ‘ En an at ks Bia Pasta a8 wat cae Reda pet Ct * “ie Bo oat al PROCEEDINGS OF THE American Philosophical Society HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE VOLUME XLVII 1908 PHILADELPHIA THE AMERICAN PHILOSOPHICAL SOCIETY 1908 —~ PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE VoL. XLVII JANUARY-APRIL, 1908. No. 188. Stated Meeting January 3, 1908. Treasurer JAYNE in the Chair. The decease of the following members was announced: Dr. Coleman Sellers, at Philadelphia, on December 28, 1907, et. 80. Prof. Thomas Day Seymour, at New Haven, on December 31, ‘1907; zt. 59. The judges of the annual election of officers and councillors held on this day, between the hours of two and five in the afternoon, reported that the following named persons were elected, according to the laws, regulations and ordinances of the Society, to be the officers for the ensuing year. ‘ President: William W. Keen. Vice-Presidents: George F. Barker, William B. Scott, Simon Newcomb. Secretaries: I. Minis Hays, James W. Holland, Arthur W. Goodspeed, Amos P. Brown. 2 MINUTES. Curators: Charles L. Doolittle, William P. Wilson, Leslie W. Miller. Treasurer: Henry La Barre Jayne. Councillors: (To serve for three years.) Hampton L. Carson, Harry F. Keller, Talcott Williams, Francis B. Gummere. ' Stated Meeting January 17, 1908. Councillor ROoSENGARTEN in the Chair. A letter was received from the American Institute of Electrical Engineers, inviting the Society to be represented at the Memorial Exercises in honor of Lord Kelvin, to be held on January 12, at 3 P. M.; and from Vice-President Scott announcing the appoint- ment of Mr. Andrew Carnegie and Professor Michael I. Pupin to represent the Society on the occasion. A letter was received from the Committee of Organization of the First Congress of Chemistry and Physics in memory of the cele- brated Russian Chemist, Mendéléeff, announcing that the Congress will be held at the University of St. Petersburg on the second to the twelfth of January, 1908. The decease was announced of Professor Charles Augustus Young, at Hanover, N. H., on January 3, 1908, zt. 78. Proressor Leo Loes read a paper on “ Tumor Growth and Tissue Growth.” (See page 3.) TUMOR GROWTH AND TISSUE GROWTH. By LEO LOEB. (Read Janiiary 17, 1908.) In the course of the last five years, partly through the aid of their respective governments and partly through private initiative, institutions have been founded in the majority of civilized countries for the investigation of the causes and the conditions of growth of malignant tumors; or, as briefly named, for the investigation of cancer. This fact proves more clearly than anything else could do the widespread interest that has recently been aroused in this part of pathological research. Pathological investigations share with those of other sciences a double nature. On the one hand, their problems are of a practical character. Pathology wants to find the causes of diseases and the conditions that favor and inhibit their progress, in order to lay a firm and scientific basis for their cure. In this respect, pathology is an applied, a technical science. On the other hand, pathology desires to analyze the conditions that ulti- mately lead to death, in order to recognize some of the phenomena of life. In that sense, pathology is a pure’ science; its aim is philosophical. Tempting as it might be to relate something of the first attempts of pathology to find the cause and the cure of cancer, I shall here, rather, turn to the purely theoretical aspects of these investigations and indicate some of the results of tumor investigations that have some bearing upon one of the fundamental characteristics of living matter—the ability to grow. Before entering, however, upon a nec- essarily very limited discussion of some of the relations between tissue and tumor-growth, it might be well to indicate what a tumor is; and, especially, what a cancer is. Perhaps I can best approach this delicate task by stating some varieties of growth that are not included under the term tumors. 3 4 LOEB—TUMOR GROWTH AND TISSUE GROWTH. | [january 17, Our bodies consist of cells (that is small parts of protoplasm with nuclear material), of products of cells of different kinds, of decom- position products of cells and of material used for the building up of cells. Here we are concerned with the two former only, namely, with the cells and their direct products. Now growth is based upon an increase in the number or the size of cells in the locality, where growth takes place. The increase in the number of cells can be brought about in two ways: either through the multiplication of pre- existing cells, or through a wandering in of new cells. Cell-growth can take place under various conditions. If toxic substances—the products of bacteria for instance—or even if inert substances foreign to the body are introduced into the organism, a certain proliferation of the neighboring cells and immigration of cells from the blood- and lymph-vessels take place. After a certain period, such reactions come to a standstill, and scar tissue develops. Such a cell-prolifera- tion we do not call a true tumor; but we class it among the inflam- matory reactions. There are other conditions in which an unusual cell-proliferation takes place in the adult organism; in cases of wound healing. If, for instance, a wound is made in the skin, the cells of the epidermis proliferate until the wound is closed; then the additional prolifera- tion ceases. We call this regenerative growth. It lasts only as long as the continuity of the epidermis is interrupted. This is not tumor-growth. We now come to a third variety of cell-proliferation, distinct from the two former varieties. If a follicle of the ovary ruptures at the time of menstruation, the follicle cells enlarge, and proliferate much more extensively than would be necessary in order to insure wound-healing. There is formed a new growth, which exists for a limited period and then disappears. A still more striking example of this new formation was found in our laboratory in the course of the past year. If, at a certain period after copulation has taken place, or at the period of heat, the inner surface of the uterus is sufficiently exposed and cuts are made in the wall of the uterus, we find that, instead of the ordinary wound-healing, another process takes place, namely: the development of nodules of new tissue, which resembles closely the maternal part of the placenta—without, 1908. ] LOEB—TUMOR GROWTH AND TISSUE GROWTH. 5 however, an ovum being in this case responsible for the new forma- tion; but also in this case the experimentally new-formed decidua, as we call this tissue, dies. The latter variety of growth resembles much more closely the real tumor-growth than do the former ; but in this case also the cell- proliferation, and even the life of the newly formed cells, cease, when the cause for the proliferation has disappeared. The cause for the development of an artificial decidua is probably two-fold: in the first place, a general chemical condition exists in the body at that period; and, under these predisposing conditions, a local stim- ulus suffices to produce the tumor-like growth. These new forma- tions might be called transitory tumors, because they have a definite life-cycle ; they grow for some tithe, and then they disappear. In real tumors we find a similar but still more marked cell- proliferation ; and they do not have such a definite life-cycle. Real tumors do not retrograde usually, and may even grow, more or less, during the lifetime of the bearer. Furthermore, we do not know the cause of their origin, as we do in the case of the transitory tumor. They grow, and we do not know why. If such tumors grow more rapidly, and especially if they grow deep into the sur- rounding tissue, digesting it, if parts penetrate into the blood- or lymph-vessels and are carried away to distant parts of the body, and here start a new growth, a so-called metastasis, then we call the tumor malignant, or a cancer. We distinguish different varieties of cancer, according to the tissue or variety of cells from which these cancers originate. The malignant tumors derived from epithelial surfaces or gland cells, we call carcinomata and the malignant tumors derived from the connective-tissue cells, which unite the functionally more highly developed cells, we call sarcomata. But from whatever tissue these malignant tumors are derived, their main characteristics are identical. During the second half of the last century, pathologists studied very carefully the microscopical character of the different tumors ; and they determined quite accurately the genesis of these tumors from normal tissues. They observed how cells began to grow down into the adjoining tissues in cancer; they described the general spreading out of the new formation, and the character of the sec- 6 LOEB—TUMOR GROWTH AND TISSUE GROWTH. [january 17, ondary growth; they also determined that a certain number of tumors apparently originate in tissue that has been misplaced during embryonic development. In other cases, long irritation, and occa- sionally a traumatism, may be held responsible for the origin of cancer. Apparently, however, no further progress could be made by these means of observation. The investigations seemed to have arrived at a dead point. After a few isolated previous attempts, mainly since the year 1899, the attention of the investigators was directed to the occur- rence of tumors in animals; to the fact that cancer in animals fre- quently occurs endemically. This means that a number of animals are affected with cancer simultaneously in a certain locality. Fur- thermore, they observed that certain kinds of tumors are charac- teristic for certain species of animals; and that the tumors occurring endemically in a species of animals are all of the same type. _ The most important fact, however, which was fully developed only within the last eight years, is that it is possible to transplant a certain number of cancers into other animals of the same species. Many at- tempts have been made to transplant cancers into animals of other spe- cies and make them grow!in these animals, but without any success. A certain kind of cancer found in the dog can be made to grow in some related species, as, for iristance, in the fox. Other tumors found in white rats may be transplanted into hybrids between white and gray rats, and the cancer of white mice can occasionally be made to grow in gray mice. The cancer of a Japanese mouse could not be success- fully transplanted into white mice, however, but only into the Japa- nese mice. No such tumors can be transplanted into more distantly related animals, nor can the cancer of man be transplanted into lower animals. A very malignant tumor from a mouse can occasionally be made to grow for a few days in a rat, but the growth soon stops. In a similar way, normal tissues of the body, for instance the epithe- lium, may be transplanted into other animals of the same species, and kept there alive after an initial growth; but if transplanted into an animal of another species, it grows for a short period and then it dies. Some tumors, and probably the majority of them, can be trans- planted only into the same animal in which they have originated. 1908] LOEB—tUMOR GROWTH AND TISSUE GROWTH. 7 Here they live, and even grow; while in other animals of the same species, they die very soon after transplantation. This probably applies to most of human tumors. The same holds good of certain animal tissues and organs; as, for instance, the ovary. They can much more easily be transplanted into the animal of which they have formed an integral part, than into other animals of the same species. 3 There exists another point of similarity between the transplanta- tion of normal tissues and organs, on the one hand, and of tumors, on the other: in both cases, after transplantation, only the peripheral parts of the transplanted piece usually remain alive ; the central part, which is not well supplied with lymph or blood from the host, soon dying. This similarity between the behavior of normal tissues and of tumors after transplantation can be easily explained, if we con- sider that in both cases we have equally to deal with the inoculation of cells or tissues from an animal organism; and that the trans- planted tumor, as can be readily shown by microscopic examination, grows merely from the transferred tumor-cells themselves, and not from the tissues of the receiving host-animal. a On the other hand, however, there exist also some very interest- ing differences between the growth of normal tissues and of tumor- tissues after transplantation, the former always growing only very slowly for a time, and then ceasing to grow, or merely remaining alive after transplantation; and the latter continuing to grow rap- idly, and sometimes continuing to infiltrate the surrounding host- tissue and to make metastases. Their character is not markedly _,modified through transplantation. Eight years ago I transplanted a sarcoma of a white rat into more than forty generations, without an appreciable decrease in the energy of growth of the tumor cells. The fact that it is possible to propagate tissues of the animal body through years and years in other animals of the same species, without any loss of vitality and power of propagation of the tumor-cells, while they would long since have died if they had remained in the animal to which they originally belonged—suggests, it seems to me, a consideration of great biological significance, namely, the question whether our own body-cells are all equally mortal, or whether their death does depend upon their accidental connection with other cells and with 8 LOEB—TUMOR GROWTH AND TISSUE GROWTH. [January 27, an organism that dies, and because a certain number of cells, espe- cially of nervous character, cannot survive. The inevitable fate of all metazoan organisms is death; and this conception deeply influenced all our valuations and directions of thought, as Metchnikoff only recently pointed out in his book on the “Nature of Man.” Weismann added one consoling idea: not all of our cells must necessarily die, but only the so-called somatic cells ; the germ-cells, ova and the sperm-cells, of each individual may propagate forever, may be immortal. The results of the tumor investigations just mentioned may, perhaps, enlarge the number of cells that may remain alive for so long a period that we cannot see the end at present; ordinary somatic cells may propagate through many generations, long after their brother cells that remained in the original organism have been transformed into simple chemical substances, and who can at present deny the possibility that they may have the potentiality of immortality, as well as the germ cells? Thus the work on tumors leads us into different realms of general biology, and opens up new fields that are not without interest. The experimental work on tumors has given some other results of an unexpected nature. One of the great achievements of the last century was the development of bacteriological technique by which it is possible for us not only to cultivate bacteria on artificial culture- media, but also to influence markedly their behavior, functions, vital- ity, and virulence. It has been found to be possible to raise the viru- lence of certain bacteria by inoculating them into animals through several generations ; on the other hand, it is possible to decrease their virulence by subjecting them to certain injurious chemical or physical , agencies. Such a bacterial culture with artificially decreased viru- lence has been used as a vaccine; that means, as a substance that, when inoculated into human beings or animals, without causing the disease, confers immunity against the virulent bacilli. In experimenting with tumor cells, the surprising result was obtained that, through successive transplantations, by cutting out pieces of tumor, an artificial stimulus is given to the tumor cells, so that they begin to grow more rapidly and more extensively. In other words, their virulence has been increased. This is due to a direct stimulating action upon the tumor cells, and not to secondary 1908.] LOEB—TUMOR GROWTH AND TISSUE GROWTH, 9 conditions. This explains a fact very familiar to surgeons; namely, that after an operation a recurrent tumor is frequently more malig- nant than the original tumor. But it is also possible to decrease the power of propagation of tumor cells without killing them by exposing the cells to chemical and physical injurious influences, in a way similar to that pursued in the case of bacteria. Here, also, we may, not without some hope, look forward to the preparation of some vaccine that may, some day in the future, help us to combat the dreaded disease. Even in this case, however, tumor tissue probably differs only in degree, and not in principle, from normal tissue. At least, this conclusion is indi- cated by the fact that such an organ as the normal thyroid gland may, without being entirely destroyed, be markedly weakened in its power of growth through a short exposure to the air before trans- plantation. There exist, however, some interesting differences of another kind between tumor tissue and normal tissues or organs. Normal organs have a specific metabolism and, in connection with or as a part of this metabolism, they exert distinct specific functions. We understand by functions those physical and chemical processes which attract our attention by their real or apparent significance for the organism as a whole. The normal female mammary gland, for instance, secretes milk under the influence of certain chemical stimuli which are present in the circulation at the end of pregnancy ; and it also grows during pregnancy, under the influence of similar stimuli. If we now transplant the mammary gland of a nonpreg- nant animal into a pregnant animal, the foreign transplanted gland may secrete milk at the end of pregnancy in a similar way to that of the animal’s own gland. The circulating chemical substance exerts the same stimulus upon the transplanted as upon the autoch- thonous gland, and the transplanted gland responds to the stimulus in the normal way. There exist certain conditions in which a tumor-like hypertrophy of the mammary gland is found in the white rat. The structure of the gland is slightly modified, but the tumor is not infiltrating. We do not call it a cancer, but a benign tumor—an adenoma. If we transplant such a tumor to another place in the original animal, it 10 LOEB—TUMOR GROWTH AND TISSUE GROWTH. [January 17, heals, and if the animal becomes pregnant, it begins to grow in the same way as the normal gland, but is no longer able to produce milk. It responds, therefore, only to certain stimuli, but not to others. If we persist still further and transplant a malignant tumor, a cancer, of the mammary gland, we find that it no longer responds to the stimuli of pregnancy. Such tumors do not seem to assume a more rapid growth, nor do they ever secrete milk. The metabo- lism of tumors differs, however, only in a greater or less degree from that of the corresponding normal tissues; and the tumor tissue can even still continue to secrete certain substances in a similar way to the normal tissues. This has been observed, for instance, in the case of the tumors of the liver and of the thyroid gland, which latter provides a\so-called internal secretion, without which widespread changes would take place in our body. It seems, therefore, in the case of the tumor tissues that there exists a parallelism between its loss of function and its capability to respond to chemical stimuli in the body that normally excite and regulate function and growth. These observations bring us also nearer to an understanding of tissue growth and tumor growth in general. Just now we men- tioned substances of various kinds circulating in the body that regu- late the growth of normal tissues and of tumors; but there probably exist a number of such substances. How else could we explain the fact that the majority of tumors may be successfully transplanted into the organism in which the tumor had originated, but not into - other individuals of the same species? Evidently there must exist some difference between the chemical composition of the blood and lymph of each individual of one species ; and each tissue of one indi- vidual is more or less adapted to its own body fluid. Furthermore, we have seen that tissues do not grow in animals belonging to dif- ferent species; there must, therefore, exist substances regulating growth, which are the same in the same species, but differ in dif- ferent species. Sometimes, however, certain families of white mice differ among one another to a higher degree than the white mice differ from gray mice. Such substances, however, can merely regulate the growth of normal tissue and of tumor tissue; they are not able to transform normal tissue into tumor tissue. How the latter transformation is 1908. ] LOEB—TUMOR GROWTH AND TISSUE GROWTH. 11 brought about, we do not yet know; and this is one of the problems that remain before us. Of one fact we may be reasonably certain ; namely, that the growth-regulating substances to which we referred just now are, in all likelihood, not the primary factors in the produc- tion of tumors. We draw this conclusion because the action of such substances has so far not been shown to be hereditary. They in- fluence the growth as long as they are present. If we liberate tissues or tumors from their influence these substances lose their effect at once or relatively soon. If, however, we are able to transplant cer- tain tumors through forty generations of animals and if the tumors preserve their character as tumors, notwithstanding the individual differences of the different animals into which they are transplanted, then there must be present some factor in or near the tumor cells themselves that constantly stimulates their growth and stirs them restlessly to new activity, until through their activity they destroy their host, and thus prepare their own end. What the character of this local stimulus is, we do not yet know. All the discoveries of organisms that have been announced from time to time were found | to be based upon erroneous observations; but that does not exclude the possibility that, after all, a microorganism in intimate relation with the tumor cell is the local stimulus acting on the tumor cell. There are two discoveries that, in themselves of interest, promise to give us a foothold from which to attack successfully this problem: In the first place the endemic occurrence of tumors among animals, to which we alluded above. Here we,can determine whether it is caused by hereditary conditions, or whether it is due to microdrgan- isms or environmental factors. Secondly, the surprising fact we learned three years ago, that if we inoculate one kind of tumor, an epithelial tumor, a carcinoma, into animals, the carcinoma, in a certain number of cases, causes the surrounding connective tissue to assume, likewise, a cancerous growth. We have here, therefore, actually succeeded in producing a new tumor, a sarcoma. Such a fact was entirely unforeseen. It could be discovered only through the experimental method of investigation. The more unexpected a new fact, the more welcome it is; the more it promises to change existing conceptions and to open up new roads, where before no way out could be seen. 12 LOEB—TUMOR GROWTH AND TISSUE GROWTH. [january 27, Lastly, the first steps have already been taken to find a rational way of curing cancer by procuring immunity in a similar way to that by which we are able to cure a certain number of infectious diseases. Protective sera can not only be prepared against bacteria, against toxins, but also against cells; and probably also against tumor cells. The beginning has been made. Certain tumors in animals have been made to disappear in such a way. Let us hope that the future holds still better results, and that we shall be able to alleviate suffering and to gain a deeper insight into conditions that determine the fate of living matter. Stated Meeting February 7, 1908. Councillor RoSENGARTEN in the Chair. A letter was read from the Fourth International Congress of Mathematics, announcing that the Congress will be held at Rome, April 6-11, 1908. PROFESSOR EpGAR OpELL Lovett presented a report on the “Lecon sur l’intégration des Equations différentielles aux dérivées partielles professées, a Stockholm (Février-Mars 1906) Sur l’invita- tion de S. M. le Roi de Suéde par M. V. Volterra, Senateur du Royaume d’Italie, Professeur de Physique Mathématique a l’Uni- versité de Rome.” He also presented a paper on “ Integrable Oases of the Problem of those Bodies in which the Force Function is a Function only of the Mutual Distances.” PROFESSOR Horace C. RicHarps and ProFessor ArTHUR W. GOODSPEED read a paper on “Recent Advances in Color Photog- raphy.” Photographs by the Lumiére process were exhibited by Dr. Hartzell and Dr. W. P. Wilson. Stated Meeting February 21, 1908. Treasurer JAYNE in the Chair. Dr. J. H. Hart read a paper on “ Artificial Refrigeration.” 1908.] MINUTES. 13 Stated Meeting March 6, 1908. Secretary HoLLanp in the Chair. Letters were read from the Secretary of the Committee of Organization of the Fourth International Congress of Mathematics, to be held at Rome, Italy, April 6-11, 1908, inviting the Society to be represented at the congress, and Vice-President Simon Newcomb was appointed as the Society’s delegate. Stated Meeting March 20, 1908. Curator MILLER in the Chair. The death was announced of Sir Samuel Davenport, of Adelaide, Australia. Dr. GEoRGE Byron GorDON read a paper on “Some of the Results of the University of Pennsylvania Expedition to Alaska, 1907.” Stated Meeting April 3, 1908. Councillor ROSENGARTEN in the Chair, Letters were received from the Secretary of the Smithsonian Institution informing the Society that the Institution has learned through the Department of State that the Second International Archeological Congress will be held at Cairo, Egypt, on the date of the Latin Easter, 1909, and requesting that the Institution be apprised of the names of scholars likely to attend the Congress. Dr. LeonArD Pearson read a paper on “Some Aspects of the Production and Distribution of Milk.” General Meeting, April 23, 24 and 25, 1908. Vice-President Scott in the Chair. April 23, Afternoon Session. A letter was received from the College of Physicians, of Phila- delphia, inviting the President to be present on April 29, 1908, at 14 MINUTES. [April 24, the laying of the corner-stone of the new building of the College. Owing to the absence of the President in Europe, Secretary James W. Holland, M.D., was appointed to represent the Society at the ceremony. The following papers were read: ‘ “The Law of Oresme, Copernicus and Gresham,” by THomas WiL.LiInG Batcu, of Philadelphia. “The Dramatic Function of Cassandre in the Oresteia of ZEschylus,” by PRoFEssorR WILLIAM A, LAMBERTON, of Philadelphia. “ Goethe’s Private Library as an Index of his Literary Inter- ests,” by PROFESSOR WATERMAN T. Hewett, of Ithaca, N. Y. “ Art and Ethnology,” by Epwin Swirt Batcu, of Philadelphia. , “Cytomorphosis, A Study of the Law of Cellular Change,” by PROFESSOR CHARLES SEDGWICK Minot, of Cambridge. “ Preliminary. Report on the Brains of the Natives of the Anda- man and Nicobar Islands,” by Proressor E. A. SpitzKa, of Phila- delphia (introduced by Professor J. W. Holland). “ Observations regarding the Infliction of the Death Penalty by Electricity,’ by Proressor E. A. SpitzKa, of Philadelphia (intro- duced by Professor J. W. Holland). “The Brain of Rhinochimaera,” by Professor Burt G, WILDER, of Ithaca, N. Y. April 24, Morning Session. The following papers were read: “A Comparison of the Albino Rat with Man in Respect to the Growth of the Brain and of the Spinal Cord,” by Proressor HENRY H. Donatpson, of Philadelphia. (See Journal of Comparative Neurology and Psychology, Vol. XVIII, No. 4, 1908.) “Preliminary Report upon a Crystallographic Study of the Hemoglobins: A Contribution to the Specificity of Vital Substances in Different Vertebrates,” by PRorEssors EpwAarp T. REICHERT and Amos P. Brown, of Philadelphia. “Recent Discoveries in the Pathology of Rabies,” by Mazycx P. RAvVENEL, M.D., of Madison, Wis. “The Explosion of the Saratoga Septic Tank,’ by PRoressor Witxi1AM Pitt Mason, of Troy, N. Y. 1908.] MINUTES. 15 “Determination of Dominance in Mendelian Inheritance,” by Cuarves B. Davenport, Ph.D., of Cold Spring Harbor, N. Y. “Inheritance in Protozoa,” by Proressor HERBERT SPENCER JENNINGS, of Baltimore. “The Excretory Organs of the Metazoa: A Critical Review,” by Proressor THomas H. Montcome_ery, Jr., of Austin, Texas. “The Classification of the Cetacea,” by Dr. F. W. True, of Washington. “ Additional Notes on the Santa Cruz Typotheria,” by W. J. Sinciair, Ph.D., of Princeton, N. J. (introduced by Professor W. B. Scott). Afternoon Session. The following papers were read: “Further Researches on the Physics of the Earth, and espe- cially on the Folding of Mountain Ranges and the uplift of Plateaus and Continents produced by movements of Lava beneath the Crust arising from Secular Leakage of the Ocean Bottom,” by Dr. T. J. J. SEE, of U. S. Naval Observatory, Mare Island, Cal. “Stratigraphic Observations in the Vicinity of Susquehanna Gap, North of Harrisburg, Pa., by GitBErT vAN INGEN, of Prince- ton, N. J. (introduced by Professor W. B. Scott). “Some Chilean Copper Minerals,” by Proressor Harry F. KELLER, of Philadelphia. “Progress of Demarcation of the Boundary between Alaska and Canada,” by Prorrssor O. H. Tirrmann, of Washington. “The Leaf Structures of the Bermuda Sand Strand Plants,” by PROFESSOR JOHN W. HarsHBERGER, of Philadelphia. “The Influence of Heat and Chemicals on the Starch Grain,” by Proressor Henry KRAEMER, of Philadelphia. “ A Contribution to a Knowledge of the Fungi of Pennsylvania ; Gasteromycetes,” by D. R. Sumstine, of Wilkinsburg, Pa: (intro- duced by Dr. A. E. Ortmann). April 25, Executive Session. The pending nominations for membership were read and the Society proceeded to an election, and the teller of election reported PROC. AMER. PHIL, SOC., XLVII. 188 B, PRINTED JULY II, 1908. 16 MINUTES. [April 25. that the following candidates had been elected to membership : Residents of the United States: Martin Grove Burmbaugh, Ph.D., Philadelphia. Walter Bradford Cannon, A.M., M.D., Boston, Mass. James Christie, Philadelphia. William Hallock, Ph.D., New York City. Edward Washburn Hopkins, Ph.D., LL.D., New Haven, Conn. Leonard Pearson, B.S., V.M.D., M.D., Philadelphia. Josiah Royce, Ph.D., LL.D., Cambridge, Mass. Jacob G. Schurman, Ph.D., Ithaca, N. Y. Charles Henry Smyth, Ph.D., Princeton, N. J. Herbert Weir Smyth, Ph.D. (Gottingen), Cambridge, Mass. Henry Wilson Spangler, M.S., Sc.D., Philadelphia. Edward Anthony Spitzka, M.D., Philadelphia. John Robert Sitlington Sterrett, Ph.D. (Munich), Ithaca, New York. Richard Hawley Tucker, Mt. Hamilton, California. - Robert Williams Wood, Ph.D., Baltimore. Foreign Residents: Ernest Nys, Brussels. Albrecht F. K. Penck, Ph.D., Berlin. Morning Session, 10.30 o'clock. The following papers were read: “The Solution of Algebraic Equations in Infinite Series,” by PROFESSOR PrREsTON A. LAMBERT, Of Bethlehem, Pa. “The Investigation of the Personal Error in Double Star Measures which depend on the Position Angle,” by Mr. Eric Doo- LITTLE, of Philadelphia. “Some Results of the Ocean Magnetic Work of the Carnegie Institution of Washington,” by Dr. L. A. Bauer, Director of the Department of Terrestrial Magnetism, Washington (introduced by President Robert S. Woodward). ‘ . «os nee 24.6 peat 2. Sylvian-presylvian junction ..............see08 28.2 ‘Aspect 3. Ventral end of central fissure................- 41.3 P 4. Sylvian episylvian junction .............-.00- 55.0 6. Frontal edge of callostm:...<:7.<../c.0eeuen 18.3 i 7- Porta (Foramen of Monro)......i..eeeccceee 37-7 Right 8. Dorsal end of central fissure............2e0e0- 61.2 Mesal 9. Dorsal intersection of paracentral fissure...... 63.8 Aspect | 10. Caudal edge of callosum.............ceeceeees 63.8 11. Occipito-calcarine junction ...........eeeeeees 75.4 12. Dorsal intersection of occipital fissure...:..... 87.4 JEFFERSON MEDICAL COLLEGE, PHILADELPHIA. DETERMINATION OF DOMINANCE IN MENDELIAN INHERITANCE. By CHARLES B. DAVENPORT, Pu.D. (Read April 25, 1908.) The longer one investigates the phenomena of heredity the more One is impressed with the grandeur of the discovery made over forty years ago by Gregor Mendel. His method is not less important than its results. Following him, in studying heredity one considers a single character at a time. One notes the result in the offspring when this character assumes contrasted forms in the two parents or when one parent has the character and the other lacks it. Under these circumstances one frequently, nay, usually, finds that the con- dition in one parent dominates over that in the other parent, so that the offspring are all alike, and like one parent, in respect to that character. The opposite, or recessive, quality is not lost, however. It persists in the germ plasm and one half of the germ cells of the individuals belonging to the first generation.of hybrids contain the dominant and one half the recessive quality. Dominance, it will be observed, it a matter of the soma. The hybrid fertilized egg contains both contrasting qualities and so, probably, do all of the cells of the body. But only one of the quali- ties ordinarily makes its appearance. It has been suggested that a struggle occurs between the contrasted qualities and the stronger— called the dominant—wins. The question is what determines this assumed greater strength of the dominant quality? What determines dominance? Various replies have been given to this question. It has been suggested that the dominant quality is the older and although this is sometimes true it so often fails to be so that age cannot be regarded as the primary cause of dominance. Frizzling and silki- ness of fowl’s feathers are each novelties but one dominates over the ordinary flat feather and the other is dominated by it. Much evi- 59 60 DAVENPORT—DETERMINATION OF DOMINANCE _s[Aprilas, dence of this sort could be adduced proving the insufficiency of the theory of the recessive nature of novelties. A different theory has been suggested by deVries, namely, when an individual having the characteristic patent is crossed with one in which it is latent the patent characteristic is dominant, the latent recessive. A similar expression has been proposed by Hurst who concludes that the pres- ence of a quality usually dominates over its absence. This expres- sion of the facts is, in the main, true but it is too narrow, inas- much as it assures that the mendelian result occurs only when a character is crossed with its absence; but this I shall show directly is by no means true. Two years ago I suggested that a progressive variation, one which means a further stage in ontogeny, will dominate over a con- dition due to an abbreviation of the ontogenetic process—or a condi- tion less highly developed than the first. Recent studies have thrown additional light on this matter and I wish to treat it now generally. First let me present some illustrations. Many poultry have feathers . on the feet ; these constitute the so-called boot. If a “booted” bird be mated with a non-booted all offspring are booted—booting is dominant over its absence. Booting occurs, however, in an infinity of grades. For convenience I recognize ten, usually determined by inspection. If a bird with a boot of grade 8 or 9 be crossed with a bird with boot of grade 2 or 3, both being pure dominants, then the stronger condition is dominant in the offspring, so that their average grade is about 8. A second illustration may be drawn from certain studies made on the asparagus beetle by Dr. F. E. Lutz, of the Carnegie Insti- tution of Washington. In the embryonic condition the outer wing covers of this beetle are nearly pigmentless or yellow. Before 1908.] IN MENDELIAN INHERITANCE. 61 emerging from the pupal condition black pigment is laid down. The pigmented area is variable in amount. The more extensively pig- mented condition is dominant over the less extensively pigmented (a over c, d or e—see Fig. 1). In this case, also, it is clear that the facts are better expressed by the statement that the more developed condition dominates over the less developed. Still another case is that of human eye color. The pigmentation of the iris is variable in amount. The blue iris is without pigment. A small amount of black pigment (with or without yellow) produces the grays; still more pigment yields browns and blacks. Now it appears that the offspring of parents one of whom has gray eyes and the other blue eyes will have gray eyes or blue eyes, but not brown eyes; and gray will show itself dominant over blue. Simi- larly brown iris color is dominant over gray; the more advanced condition of. pigmentation over the less advanced. We have not here to do with a qualitative difference of the presence of a character opposed to its absence, but of a qualitative difference only. The heredity of human hair color follows a similar law. In one series red pigment is absent in the hair and such colors as flaxen or tow, light brown, brown, dark brown and black may be distin- guished. The records collected by Mrs. Davenport and myself show that two flaxen-haired parents have flaxen-haired children and probably only such. Two parents with light brown hair have chil- apparently only such. Two parents with light brown hair have chil- dren of two parents each with dark brown or black hair produce children with all of the varieties of hair color. This result means that any lighter color is recessive to any darker color. The facts recited above and many others thus support the view that, where various stages, a, b, c, in the progressive development of a quality are found in individuals of the same race or species, the more progressive condition will often behave as a dominant toward the less progressive condition. The extreme case is, of course, that in which the organ or quality is absent in one parent and present in the other; but this seems to be only a special case of a more general law. As to the universality of this law it is still early to speak with confidence. We know too little of the developmental factors of an 62 DAVENPORT —DETERMINATION OF DOMINANCE [April 25, organ to decide, in many cases, whether a difference is due to a progressive or a retrogressive change. For instance, the long angora coat of rabbits is recessive to short coat; and this has been cited as a clear case of recessiveness of the advanced condition. But it seems doubtful if such is the case. For the angora coat retains an embryonic quality (viz., of continued growth) which is present in the infancy of the short-haired rabbit and is then inhibited. The inhibiting factor is present in short-haired rabbits and absent in angora rabbits and the presence of the inhibiting factor dominates over its absence. At one time I thought that the dominant white plumage of some poultry was a case of dominance of absence of color. But it now appears that we have among poultry recessive whites which are true albinos, and the dominant whites which must be regarded as “ grays,” in which pigmentation is obscured by an additional factor like that which turns black hair gray. This gray- ing factor is dominant over its absence. It is possible that the future may show that, in accordance with the ideas of deVries, an advanced grade of a character may be regarded as a sum of minute equivalent elementary units; by the dropping out of these units one at a time a character passes through a series of degradational stages. Then a light brown hair may have one unit of melanic pigment, brown hair two units, dark brown three units, and black hair four units. If this should prove to be true then the four unit condition would dominate over the three unit condition, or the fourth unit would dominate over its absence. But such evidence as I have at present does not favor this view. I am inclined rather to the hypothesis that when the germinal deter- miner of greater intensity meets that of less intensity it dominates over the latter. This hypothesis receives support from another set of facts which go to prove that the idea of varying intensity of a determiner is a true one. This set of facts is derived from the combs of poultry. In one race of poultry—Polish fowl—the comb consists of a pair of horns or broad flaps which lie far back near the base of the beak; and there is no median comb. In the Minorca and most other fowl there is a single median comb. Now when these two races are crossed we find that the median comb dominates over the absence of median comb; sometimes completely, running in the 1908. ] IN MENDELIAN INHERITANCE. 63 hybrid from the base of the beak to in front of the nostrils ; some- times incompletely, occupying only the anterior half or fourth of the beak. It seems to me clear that in the varying proportions of this median comb in the hybrids we have at once evidence for, and a measure of, varying intensity of dominance. Now it may reason- ably be asked whether, when the long-combed and short-combed hybrids are mated together, the long comb dominates over the short. The answer is complicated by the fact that the Polish “horns” reappear in this second generation; but, leaving this aside, we find that there is a greater preponderance of Jong median combs than simple mendelian expectation calls for and this indicates that the longer median comb tends, but not always perfectly, to dominate the shorter median comb; or, in other words, the more intense deter- miner dominates the less intense. ‘To sum up, I think it is clear that dominance in heredity appears when a stronger determiner meets a weaker determiner in the germ. The extreme case is that in which the strong determiner meets a determiner so weak as to be practically absent as when a red flower is crossed with a white. In such cases we have the clearest exam- ples of mendelian inheritance. But there is an entire gamut of cases where the opposed determiners are of varying relative potency. The phenomenon of determinance is seen in these cases also; but the mendelian law in them is sometimes obscured and sometimes merely not applicable. ae Coty Sprinc Harsor, Lone Istanp, N. Y., April, 1908. PROC. AMER. PHIL. SOC. XLVII. 188 E, PRINTED JULY Io, 1908. THE SANTA CRUZ TYPOTHERIA. .- (Figures 1-10.) By WILLIAM J. SINCLAIR. (Read April 24, 1908.) The Typotheria are a group of semi-ungulate mammals of strictly South American origin appearing first in the Notostylops beds of .Patagonia.t During the Santa Cruz epoch four genera are repre- sented but what is lacking in generic and specific diversity is more .than compensated for by an abundance of individuals. The total -number of common species apparently does not exceed eight, but this Fic. 1. Skull of Protypotherium australe Ameghino, side view, three fourths the natural size. (No. 9565 American Museum of Natural History collection.) has been increased to no less than fifty-one by failing to estimate at their true value characters due to age and others which seem to be of the nature of individual variations in size, the result no doubt of the extremely fragmentary character of the material hitherto available. Even with the large suites of specimens in the collections * Tsotypotherium, Epitypotherium. 64 | 1908. ] SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 65 at Princeton University and the American Museum of Natural His- tory it has been found impossible to separate in a satisfactory manner the species of the genus Protypotherium. An almost exact inter- gradation in size without appreciable difference in structure is observable between the largest species Protypotherium australe (Fig. 1) and the smallest P. attenwatum. As none of the collections have been made with strict regard to stratigraphic sequence, we are not in a position to say whether these differences represent individual variations or true mutations. The former alternative has been adopted in monographing the group (see the forthcoming Volume VI., Part I. of the “ Reports of the Princeton University Expeditions to Patagonia ”’). CLASSIFICATION OF THE SANTA Cruz TYPOTHERIA. The Typotheria are grouped by Scott? as a suborder of the Toxodontia and may be defined as follows: _ Plantigrade or digitigrade mammals with pentadactyl® or tetra- dactyl feet, strongly interlocking carpus with os centrale and serial or slightly interlocking tarsus with hemispherical astragalar head. Dentition usually complete but tending toward reduction of the lateral incisors, canine and anterior premolars in specialized forms. Median incisors more or less enlarged and functional as cropping teeth. Molars hypsodont, lophoselenodont in crown pattern, curving inward above and outward below. A clavicle is present in some forms. Femur with third trochanter. Fibula articulating with calcaneum. Two well-marked families are recognizable among the Santa Cruz representatives of the suborder for which the names Intera- theride and Hegetotheride have priority. Each contains a large and a small genus of which, in either case, the former is the less specialized. The following key to the families and genera may facilitate the determination of new material : * Scott, W..B., “The Miocene Ungulata of Patagonia,” Rept. British Asso, Adv, Sci., 1904, pp. 589-590. ® Ameghino figures a pentadactyl manus in Pachyrukhos typicus, “ Contrib. al conocimiento de los mamiferos fésiles de la Republica Argentina,” Actas de la Academia Nacional de Ciencias en Cérdoba, T. V., Pl. 13, fig. 14, 1889, and in Typotherium, ibid., Pl. 18, fig. 5. 66 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, Order TOXODONTIA Owen. Suborder TYPOTHERIA Zittel. A. Family InTerATHERIDZ. Median incisors rooted; third and fourth pre- molars not completely molariform, squamoso-mastoid region dilated and cancellous; malar long and narrow, inclosed between temporal process of maxillary and squamosal; maxillary orbital; carotid canal and foramen lacerum posterius fused; tibia and fibula unfused distally; pes par- axonic, digits II. and V. equally reduced and small, digits III. and IV. large and of equal length; astragalar trochlea bilaterally symmetrical; no naviculo-calcaneal facet; calcaneum with large fibular facet. 1. Protypotherium. Dental formula }%,+,4,% in close series. Lateral incisors unreduced; canine incisiform; upper molars with deep in- ternal inflection and slight antero-external ridges; Ms externally bilobate; temporal bar of maxillary with slight descending process; humerus with internal epicondylar foramen; terminal phalanges laterally compressed hoofs with slight clefts in manus. 2. Interatherium. Dental formula 3, }, 4, $, with diastemata between the lateral incisor, canine and first premolar, varying with the species. I? reduced, often wanting; upper molars with deep internal inflection and prominent antero-external ridges; Ms externally trilobate; tem- poral bar of maxillary with strong descending process; humerus without internal epicondylar foramen; terminal phalanges laterally compressed hoofs with or without clefts. B. Family HecrrorHEerip#. Median incisors rootless; third and fourth pre- molars molariform; mastoid dilated inclosing a large hollow cavity; malar large excluding maxillary from orbit; carotid canal and foramen lacerum posterius widely separated; tibia and fibula firmly fused both proximally and distally; pes approaching mesaxonic with digit III. the longest, digit V. greatly reduced and digits II. and IV. shorter than III. but robust; astragalar trochlea bilaterally asymmetrical; navicular and calcaneum in articulation; small fibulo-calcaneal facet. 1. Hegetotherium. - Dental formula 3,4, 4,%. Second and third upper and third lower incisor vestigial; canine vestigial; upper molars inter- nally convex, without inflection except in M*; ectoloph smooth; terminal phalanges greatly flattened transversely with prominent clefts. 2. Pachyrukhos. Dental formula }, 3, $,%. All the upper molars inter- nally convex; ectoloph smooth; terminal phalanges hoof-like without clefts in Santa Cruz species. ‘The Santa Cruz typotheres are animals of somewhat rodent-like appearance, varying in size from a cotton-tail rabbit to a cavy. A review of the more important skeletal characters of the group may be of value, even though it involve some repetition. 1908.] SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 67 Fic. 2. Skull of Interatherium robustum Ameghino, side view, three fourths the natural size. (No. 9263 American Museum of Natural History collection.) 1. The Skull.—The facial portion of the skull is slender and more or less excavated longitudinally while the brain case is broad and well expanded. The orbits are central, circular in outline, quite prominent in Hegetotherium, Pachyrukhos and Interatherium and unenclosed posteriorly. The jugal arches are robust in all except Fic. 3. Skull of Hegetotherium mirabile Ameghino, side view, three fourths the natural size. (No. 15542 Princeton University collection.) Pachyrukhos and moderately expanded. The premaxillz are short and heavy with scarcely any ascending process ; the nasals are broad posteriorly, tapering forward to blunt points; the interorbital tract plane and the sagittal and lambdoidal crests low. The most promi- 68 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, nent feature of the back of the skull is the greatly distended mastoid tract which may either be filled with cancellz or lodge a large cavity. In either case there is direct communication with the tympanic bulla and the dilation appears to have functioned as a secondary resonator, perhaps associated with nocturnal habits. The palate is concave throughout, terminating posteriorly in a pair of stout processes. The mandible is heavy and deep, without trace of suture in the firmly fused symphysis. 2. Dentition—Beginning with the normal incisor formula in Protypotherium (Fig. 1) the Santa Cruz typotheres show a well- marked tendency toward an increase in size of the median incisors at the expense of the lateral incisors, canine and anterior premolar until the extreme stage of reduction in Pachyrukhos (Fig. 4) is attained. The teeth undergoing elimination are reduced to simple cylinders. It is not to be understood that Protypotherium, Intera- therium, Hegetotherium and Pachyrukhos constitute a phyletic series because they represent successive stages in the process of dental reduction associated with the hypertrophy of the median in- cisors. As already indicated in the key to the genera, two divergent lines are represented and not a single progressive series. A rather curious feature of the lower incisors in Protypotherium is the pres- ence in the first and second of a deep median cleft producing a fork-like structure recalling a somewhat similar division of the lower incisor crowns in the Hyracoidea. In all the Santa Cruz typotheres the enamel layer on the enlarged incisors tends to be confined to the anterior surface of the crown. The molars in all the genera are constructed on much the same plan but only in Protypotherium are absolutely unworn teeth known, consisting essentially of a broadly concave ectoloph (e, Fig. 8, 4) and’a pair of crescents with the con- vexity directed inward (ac, pc, Fig. 8, A), of which the anterior horns are fused with the ectoloph inclosing a reentrant. A crista- like ridge from the ectoloph (c, Fig. 8, A) is separated from the anterior crescent by a deep notch. A slight ridge (pp, Fig. 8, 4) blocks the shallow valley inclosed by the posterior crescent. As the tooth wears the antero-external angle of the crown elongates and is channeled by a shallow groove producing the ridges noted in the key to the genera. 1908. J SINCLAIR—THE SANTA CRUZ TYPOTHERIA. | 69 In the lower molars the convexity of the crescents is reversed so that the reentrant fold is external (Figs. 1, 3, 9,.4). A prominent lobe spanning the arc of the posterior crescent (pp, Fig. 9, A) is not peculiar to the teeth of the Typotheria alone, but is present also in Nesodon (Fig. 9, B), Astrapotherium, Theosodon and other extinct ungulates from South America. In the last lower molar the devel- opment of the third lobe present in Jnteratherium is accomplished by the deepening of the shallow groove indicated in Protypotherium ‘at the point marked pe in Fig. 9, A. As mentioned in the generic key the premolars are sometimes molariform and sometimes not, differing from the molars in the latter case in having the anterior crescentic lobe smaller than the posterior. | Roots are developed only in the deciduous molars but as these have been observed only in Protypotherium and Interatherium it is Fic. 4. Skull of Pachyrukhos moyani Ameghino, side view, three fourths the natural size. (Reconstructed from several specimens.) not altogether certain whether this character is of family or sub- ordinal value. So far as can be ascertained the crown pattern seems to have been the same in the deciduous and permanent series, the milk teeth resembling their successors. The order of replacement seems to have been the normal one. A thin layer of cement is usually observable on the molars and premolars of all the genera. 3. Axial Skeleton—The dorso-lumbar vertebral formula in Interatherium is twenty-two, of which fifteen are dorsals. It was probably the same in Protypotherium but in Pachyrukhos eight lum- bars are present. Five vertebre are codssified, in the sacral com- plex of which three are true sacrals in contact with the ilium and 70 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, two belong to the caudal series. The length of the tail seems to have varied. In Protypotherium and Interatherium it is both long II iv Left hind foot of Protypotherium australe Fic. 5. Ameghino, three fourths the natural size. (No. 9149 American Museum of Natural History col- lection.) and heavy while in Pachyrukhos there is reason to believe that it was quite short. 4. Foot Structure-—Almost nothing has hitherto been known of the struc- ture of the feet in the Santa Cruz typo- theres, but definite information is now available for all the genera except He- getotherium, in which the manus is still unknown, but from the close structural resemblance of Hegetotherium and Pa- chryukhos it is probable that it was not unlike that of the latter, which in turn does not differ materially from the manus of Interatherium and Protypotherinm (Fig. 6, A). In the Santa Cruz forms both manus and pes are tetradactyl with- out the slightest trace of an opposable thumb or great toe. The carpus is strongly interlocking and shows no trace of the centrale. Two types of hind foot are developed (Figs. 5 and 7, A) simu- lating the paraxonic and mesaxonic sym- metry of the feet of the Artiodactyla and Perissodactyla. These are probably to be correlated in the Typotheria with cursorial and saltatorial modes of pro- gression. Pachyrukhos was certainly a jumping animal as shown by the greater length and strength of the hind limbs and inner digits of the pes. In fact, the structure of both the fore and hind limbs in this animal *A pentadactyl manus with separate centrale in the carpus and opposable thumb and a pentadactyl pes with large opposable hallux figured by Ameghino, Revista Argentina de Hist. Nat., 1., pp. 393, 304, figs. 95, 96 and referred to Interatherium (Icochilus) robustum do not pertain to this genus. The same figures with the erroneous determination appear also in Zittel’s “ Handbuch der Palaeontologie,” IV., p. 493, fig. 407. 1908. | SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 71 closely resembles that of the rabbit. From the numerous structural similarities between Pachyrukhos and Hegetherium it may be in- ferred that the latter was also saltatorial. Its broad, shallow as- tragalar trochlea is in contrast with the narrow, more deeply incised trochlea of the cursorial Protypotherium and Interatherium. Both of these genera have the fore and hind limbs of approximately equal length. The terminal phalanges in the Santa Cruz typotheres are hoof-like and in Hegetotherium have prominent median clefts. RELATIONSHIPS OF THE SANTA CRUZ TYPOTHERIA. 1. With the Toxodonta.—In the evolution of the teeth and feet, the Santa Cruz Typotheria are less advanced than their contempor- aries, the Nesodons. The feet of Nesodon (Figs. 6, B, 7, B) are iT It Wt Fic. 6. A. Left fore foot of Protypotherium australe Ameghino, three fourths the natural size. (No. 9149 American Museum of Natural History collection.) B. Left fore foot of Nesodon imbricatus Owen, about one fifth the natural size. (No. 15460 Princeton University collection.) tridactyle with the axis passing through the third digit. The manus has originally been tetradactyl like that of Protypotherium (Fig. 6,A) but has lost almost all trace of the fifth digit, a mere vestige, not shown in the figure, remaining. The other bones of the wrist and foot have not suffered any displacement as a result of this loss but interlock in the same way as in Protypotherium. The hind foot 72 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, of Nesodon (Fig. 7, B) is the realization of a structure already fore- shadowed in the pes of Hegetotherium (Fig. 7,A). The fifth digit, which is greatly reduced. in Hegetotherium, has here disappeared and the ento- and meso-cuneiforms have united to a single bone. The shortening of the neck of the astragalus and the increase in size of the fibular facet on the calcaneum are, perhaps, adaptations to the support of weight. Although the molars of Nesodon appear Fic. 7. A. Hegetotherium mirabile Ameghino, right hind foot, three fourths the natural size. (No. 15542 Princeton University collection.) B. Nesodon imbricatus Owen, right hind foot, about one third the natural size. (No. 15460 Princeton University collection.) exceedingly complex, owing to the development of secondary enamel folds, the primary elements can be homologised with those displayed in the simpler crown pattern of Protypotherium, as indicated by the similar lettering in Figs. 8 and 9. This comparison can not yet be 1908, ] SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 73 extended to the other Santa Cruz genera, Hegetotherium, Pachy- rukhos and Interatherium, as unworn molars of these: are not avail- able. Nesodon differs from the Typotheria in the enlargement and caniniform character of the second incisor above and the third below, while in the Typotheria the median incisor in both jaws is the only one tending toward great increase in size. In none of the Santa Cruz Typotheria is there a trace of the double deciduous dentition characteristic of Nesodon. Fic. 8. A. Unworn third upper molar of a young Protypotherium, four and one half times the natural size. (No. 9482 American Museum of Natural History collection.) B. Nesodon imbricatus Owen, second and third upper molars slightly worn, three fourths the natural size. (No. 15135 Princeton University collection.) ac, antero-internal crescent; pc, postero-internal crescent; ¢, ectoloph; c, crista; pp, posterior pillar. From these resemblances in dentition and foot structure it seems permissible to infer that the Toxodonta and Typotheria had a com- mon origin, but the facts at present available do not justify us in saying more. 2. With Typotherium.—Difficult as it is to ascertain the relation- ship existing between the Santa Cruz Typotheria and the Nesodons, 74 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, it is even more so to determine their degree of kinship with Typo- therium. From their small size it seems quite probable that none of the Santa Cruz Typotheria are in the direct line of descent culmi- nating in this genus. This is confirmed by the degree of specializa- tion in dentition and foot structure which Typotherium, displays. The teeth of the latter show a greater complexity of folding than is attained by any of the Santa Cruz typotheres, while the feet are less specialized with a pollex in the manus which has been lost in Pro- typotherium, the most generalized of the Santa Cruz typotheres Fic. 9. A. Unworn third lower molar of a young Protypotherium, four and one half times the natural size. (No. 9482 American Museum of Natural History collection.) B. Nesodon imbricatus Owen, two lower molars, three fourths the natural size. (No. 15135 Princeton University collection.) ac, anterior crescent; pc, posterior crescent; pp, posterior pillar. (Fig. 6, A), and with digit V. of the pes less reduced than in the most specialized of the latter (Pachyrukhos). A pollex has been figured by Ameghino® in the manus of Pachyrukhos typicus, but none has been found in any Santa Cruz specimen. The manus in Hegetotherium is unknown, so the above statement regarding the * Ameghino, Florentino, “Contrib. al conoc., etc.,” Pl. 13, fig. 14. 1908.] SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 75 degree of specialization in foot structure displayed by Typotherium may require some modification in the light of fuller knowledge. 3. With the Rodents—In many features of skull and skeleton the Typotheria resemble the rodents. This is most apparent in Pachyrukhos, which seems to have been a saltatorial animal, but in none of the Typotheria are the following characters peculiar to rodents developed: A. Persistently growing, chisel-shaped incisors (I. % of the per- manent series, Weber).° I. % of the permanent series is enlarged in some of the Typotheria and may grow persistently but is modified for cropping and not for gnawing. B. More or less antero-posterior elongation of the mandibular condyle and corresponding modification of the glenoid fossa to permit backward and forward movement of the lower jaw. In the Typotheria the condyle is approximately circular in outline with the glenoid surface flattened and the movement of the mandible is from side to side. C. Frequent outward curvature of the crowns of the upper molars and inward curvature of those of the inferior series in hypso- dont forms. The reverse is true in the Typotheria. D. Contact of ascending process of premaxillary with frontal. This process is short and robust in the Typotheria and is widely separated from the frontal by the maxillary. E. Elongation of the mandibular angle. The angle is evenly convex in the. Typotheria. F. The astragalus in rodents is characterized by a broad, short, rather shallow trochlea with the crests sharp and equally developed, distinct neck and flattened head, convex distally ; trochlea symmet- rical to the vertical plane; fibular and internal malleolar facets ver- tical ; body limited posteriorly ; no astragalar foramen. In the Santa Cruz Typotheria the body is deeper than in rodents, the crests may or may not be equally developed and the head is globular without antero-posterior flattening. The symmetry of the trochlea with respect to the vertical plane varies in the different families. In the other characters they resemble rodents. *“Die Saugetiere,” p. 480, 1904. 76 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, > Fi G. The presence of a free centrale in the carpus in all rodents except the Hystricide and Caelogenys and the general fusion of the scaphoid and lunar in all except the Bathyergidz, Ctenodoctilidz and Lagomorpha.’ The centrale is wanting in the carpus of the Typo- theria and the lunar is always free. H. The presence of a tibial sesamoid in all the simplicidentate rodents. This is not found in the tarsus of the Typotheria. The Typotheria resemble rodents in the elongation of the anterior ‘portion of the skull with the reduction of the incisor-canine-premolar series (cf. Figs. 3 and 4),.in the enlargement and often permanent growth of the median incisors (not homologous with the enlarged incisors in rodents, see under A, above), in the development of a mastoid dilation which may be filled with cancelle (Interatheridz) as in many rodents and connected with the auditory bulla, in the shape of the proximal articular surfaces between the radius and ulna, in the broad anteriorly directed transverse processes of the lumbar vertebre and in several other characters of minor importance. In. view of the striking differences in struc- ture indicated in the preceding paragraphs, it seems probable that these resemblances are to be explained as instances of convergence. 4. With the Hyracoidea.—A more or less intimate relationship between the Typotheria Fic, 10. Left hind and Hyracoidea is commonly assumed but foot of Procavia : : ‘ hah iBilidy shaal’. artio- with the complete material now available it is rea, 3% natural size. difficult to see on what grounds this hypothesis (No. 365 Princeton ¢an be maintained. The hyracoid carpus is University osteologi- ¥ 2 Eee aitaoticn: ) arranged on the linear plan with separate centrale while in the tarsus the astralagus is unlike that of any other mammal in possessing a large step-like articulation for the internal tibial malleolus (Fig. 10). : In striking contrast with hyrax, the carpus in the Typotheria is strongly interlocking without centrale, and the internal tibial mal- leolus is applied to the lateral surface of the astragalus without trace 7 Weber, loc. cit., p. 476. 2968.) SINCLAIR—THE SANTA CRUZ TYPOTHERIA. 77 of: the supporting shelf (Figs. 5 and 7, A). The flat astragalar head in the Hyracoidea and the articulation of the fibula with the astragalus instead of with the calcaneum are additional points of difference, all of which are more than sufficient to offset similarities -in skull structure which are confined to a few points, such as the ‘cancellous dilation of the mastoid, the shape of the posterior border of the palate, and the increase in depth posteriorly of the mandible. In the Hyracoidea the molar takes part in forming the outer por- tion of the glenoid cavity, the parietal enters into the postorbital process and the base of the coronoid just back of the last lower molar is perforated by a large foramen, a superior branch of the alveolar canal. None of these characters are exhibited by the Typo- theria. In the hyracoid dentition, the first upper incisor is a per- sistently growing downwardly curved tusk of triangular cross- section. In some of the Typotheria this tooth may grow persis- tently but it is always antero-posteriorly compressed, transversely expanded and modified for cropping, never appearing as a tusk. The molars of the Hyracoidea are lophoselenodont and either brachyodont or short hypsodont while in the Typotheria they are extremely hypsodont, developing roots only in the deciduous series. The crown pattern of the hyracoidean molar bears more resemblance to that of some of the early horses and rhinoceroses than to the molar pattern in the least specialized of the typotheres (Figs. 8 and 9). The so-called hyracoids from the Fayum Province of Egypt (Saghatherium, Megalohyrax) are as yet known only from frag- ments of the skull and dentition but, so far as the available material “permits comparison, resemble the modern Hyracoidea and not the Typotheria which would probably not be the case if the two orders were related as it would naturally be expected that a closer simi- larity should exist between the Eocene and Miocene representatives of an order than between the latter and the recent forms. All the Egyptian hyracoids have the base of the coronoid perforated by a branch of the dental canal as in the recent forms*® and unlike the Typotheria. §Communicated by Mr. Walter Granger, of the American Museum of Natural History. 78 SINCLAIR—THE SANTA CRUZ TYPOTHERIA. [April 24, Various pre-Santa Cruz genera (Archeohyrax, Argyrohyrax) have been referred to the Hyracoidea. Their foot structure is still unknown but the skull and dentition, to judge from the photographs, figures and descriptions examined by the writer, are not hyracoidean in character. Too little is known of these forms to warrant a dis- cussion of their relationship with the Santa Cruz Typotheria, but there can be little doubt that they should be referred to the same suborder. PRINCETON University, April, 1908. - NOTES ON SOME CHILEAN COPPER MINERALS. By HARRY F. KELLER. (Read April 24, 1908.) Some time ago my brother, Mr. Hermann A. Keller, presented me with a fine suite of mineral specimens collected by him on a pro- fessional trip to Chilean mining localities. The minerals, which in- clude native sulphur and copper, various oxides, chlorides, sulphates, borates and silicates, were for the most part readily identified by their characteristic appearance or by simple tests, but some of them aroused my curiosity, partly because of their rare occurrence, and partly on account of their beauty or exceptional purity. I was thus led to make a number of qualitative and quantitative analyses, the results of which appear to me sufficiently interesting to be placed on record. In the present paper I shall confine myself to the descrip- tion of some minerals containing copper as either a principal or a minor constituent. CupREOUS MANGANESE. It is well known that in many varieties of psilomelane or wad the manganous oxide is partially replaced by oxide of copper, and that special names have been given to some of those varieties in which the proportion of the latter oxide is considerable. Among them is the peloconite from Remolinos, Chile, which was first described by Richter,’ and chemically characterized by Kersten.? Its quantitative composition, however, does not appear to have been fully deter- mined. The material supplied by my brother included several very fine specimens of a cupreous manganese from Huiquintipa, Province of Tarapaca, and these are unquestionably identical with Richter’s peloconite. With the one exception of the specific gravity, the physical and chemical characters of the new material are precisely * Poggendorffs Annalen, 21, 590. 2 Schweigger’s Journal, 66, 7. PROC. AMER. PHIL. SOC, XLVII. 188 F, PRINTED JULY 10, 1908. 80 KELLER—NOTES ON CHILEAN COPPER MINERALS. [April 24, similar to those of the Remolinos occurrence. The mineral is mas- sive and amorphous, has a conchoidal fracture, a bluish-black color and a liver-brown streak. Its hardness is between 3 and 4, and the specific gravity 3.683 (instead of 2.5-2.6). When broken into small pieces and carefully picked with the aid of a lens, the material appeared quite homogeneous except for a few particles of quartz and some green or bluish specks of a copper compound on the out- side and along the crevices. A qualitative analysis showed that it contains the oxides of manganese, copper and iron, together with water and varying amounts of admixed silica. To ascertain whether the mineral has a definite chemical composition analyses were made of carefully selected samples from different specimens. It was found that the silica, which separates on dissolving the substance in hydrochloric acid, is not uniformly distributed through the mass. Its percentage varied from 12 per cent. to 32 per cent., and its microscopic examination showed that it consists entirely of quartz. There could be no doubt, then, that it is simply an admixture, and that in calculating the composition, the silica (of which only a trace dissolves with the mineral) should first be deducted from the amount of the substance taken. The results of the analyses were as follows: i. Il. Iii. IV. ORV TONS ils Soni veces cae vsossnees 14.37% 14.18% 13.89% not det. Manganous oxide............0+. 69.61 68.95 69.44 70.61 % CAPRIS CPD ash ss ve seshiceenven 5.86 6.05 5.69 6.48 Copel Ont iiis, kes icictesaen .48 56 not det. not det. MAATIGIN OKIE och ss bel cou ceteee .36 -47 not det. not det, WOITICOXIGE yay ccc ck ccocees 2.05 1.94 1.89 on A OE a ph eS a 1.92 I.gI 2.10 4. WVGLAE Sus laendsoecresssaeuess $s 5.14 5-29 99-79 %o 99-35 % It is seen from these figures that the proportions of the several constituents of the mineral are fairly constant. The composition is that of psilomelane, in which part of the manganese is replaced by copper. It is difficult to account for the very constant proportions of oxide of iron and alumina. Regarding the determinations of water and of available oxygen, I may mention that the former was made by heating the substance 1908.] KELLER—NOTES ON CHILEAN COPPER MINERALS. 81 in a current of dry air and collecting the moisture in calcium chloride, while the latter was estimated iodometrically in I. and II., and indi- rectly in III., by heating a weighed portion, first in air and then in hydrogen, and allowing for the water and the reduction of the oxides of copper and iron. As a matter of course this method is less reliable, but the result nevertheless agrees quite well with the iodometric determinations. CHALCANTHITE AND A DOUBLE SULPHATE OF COPPER AND MAGNESIUM. Among the specimens that claimed my special attention there was one’ consisting of irregular and rounded masses, and which was labeled “sulphate of copper and aluminium.” While the shape of the little lumps was about the same, three distinct kinds of material could readily be picked from the specimen, even without the help of a magnifying glass. : One of these substances had a deep blue color and was recog- nized without difficulty as chalcanthite. The blue masses were evi- dently crystals which were strongly corroded and slightly effloresced on the surface. A quantitative analysis confirmed the composition CuSO, -+ 5H,O, with very small amounts of iron and magnesium sulphates, and a slight admixture of silicious matter. It gave: Found. Calculated. Per Cent. Per Cent. PAIOTIRNE SETONIOG sic hea. ays sss he nies ote neet 32.21 32.1 PASI ONS Noone ss vo en 00s ants ew ate 31.52 31.8 PCLTOUS ORIG 5 Wis ae hn hs SR AERC i ory Magmesitam. Oxide o...o:..¢ 9:46:5 sivnieid sivi'eieib ate .ays 35 NV ALOT. ccc a heh lale WRK beats is iae eae 35-79 36.1 100.19 100.0 More interesting were the bluish-white masses which formed the larger portion of the specimen. They were earthy and friable, but presented shapes and surfaces exactly similar to those of the chal- canthite, suggesting a pseudomorph after the latter. In composi- tion, however, the material was found to differ from chalcanthite in ®From Copaquire, Province of Tarapaca. 82 KELLER—NOTES ON CHILEAN COPPER MINERALS. [April 24, that it contained a large proportion of magnesium sulphate. Anal- yses of two different samples yielded: Found. Calculated for I IL. (Cu, Mg)SO,+s5H,O: Sulphur trioxide.........-c.ssescssceeseeee 35-74% 35-67 % 35-84% Cupric Oxides ict cicsteaaeceseset ek ccs 12.41 12.46 11.89 Magnesium oxid@g..ccsierivevesccades ces 11.42 11.36 11.95 Ferrous oxide, -scisscders tila oivareeweesss -97 1.05 Manganous Oxide,...........022 seeceeees -23 -41 Nickel oxides Ge ea trace .06 Weer cee hutee ene, 38.45 38.31 40.32 99.22% 99.32% 100.00 % The conclusions to be drawn from these results are, first, that the mineral is an isomorphous mixture of the sulphates of copper and magnesium; secondly, that this double salt contains five mole- cules of water of crystallization ; and thirdly, that for each molecule of copper sulphate there are present (very nearly) two molecules of magnesium sulphate. The shortage in the water content is doubt- less owing to efflorescence, and there should be credited to the mag- nesia content an amount equivalent to the percentages of the oxides of iron and manganese. Under the name of cupromagnesite a double sulphate of copper and magnesium has been described by Scacchi. It occurs in the form of green crusts on lava from the Vesuvius, and is believed to be isomorphous with melanterite, containing, like the latter, seven molecules of water of crystallization. I have seen no reference to a mineral of the same composition as that above described. Associated with the chalcanthite and the double sulphate of cop- per and magnesium were other little masses, dirty-white in color and more or less stained with ferric oxide. They were very hard and consisted almost entirely of silica, containing only trifling amounts of oxide of iron and magnesia. It is puzzling to explain why these masses should simulate the form of the accompanying soluble sulphates. BROCHANTITE( ?) CONTAINING ARSENIC ACID. Very small quantities only were available of an emerald green mineral which was observed partly in fine acicular crystals dissemi- 1908. | KELLER—NOTES ON CHILEAN COPPER MINERALS 83 nated through a silicious rock, and partly as an incrustation upon quartz. On account of its physical characters, as well as the strong reaction its solution gave with barium chloride, I was first inclined to regard it as a typical brochantite. This impression was confirmed by rough estimations of the copper and sulphur trioxide, but as these tests had been made on impure material, I decided to attempt the analysis of a carefully prepared sample. To obtain about .5 grm. of the substance, I found it necessary to sacrifice the best specimens in my possession, and my patience was put to a severe test in picking the minute crystals under the lens. They were sorted over and over until the microscope showed only a few remaining specks of quartz adhering to the larger crystals of the copper mineral. The quartzy material from which this sample had been picked still contained considerable quantities of the copper mineral, and it occurred to me that it might serve for a qualitative, and, perhaps, a preliminary quantitative analysis. Accordingly the material was extracted with hydrochloric acid, and the resulting green solution divided into equal parts. When the copper had been precipitated with hydrogen sulphide, it was noticed that yellow flakes began to form, and after the liquid saturated with the gas had been allowed to stand in a warm place over night, a considerable amount of the yellow precipitate had settled on the black copper sulphide. There could be no doubt, then, that arsenic was present in the form of arsenic acid. The sulphides were separated and worked up in the usual manner, and the filtrate was searched for other metallic ions. It yielded only traces of iron oxide and alumina. The other half of the original solution was used for the determination of the sulphur trioxide and the arsenic acid. The results of the determi- nations, calculated for the entire amount of copper mineral dissolved, gave: CODGOE Se inc 'cs Fak Saree See tee ab eee .5068 grms. Sulphur: trioxide. ica ates eae .0783 grms. Arsenic atthydride) osc /g cages she sees ss .1309 grms. The question now arose as to whether the very large proportion of arsenic acid found really constituted an integral part of the sup- posed brochantite, or whether it did not belong to another mineral contained in the rock. The test previously made seemed to preclude such an arsenic content of the mineral under examination. 84 KELLER—NOTES ON CHILEAN COPPER MINERALS. [April 24, In view of the very limited amount of material available for analysis, it seemed best to dispense with the water determination and confine the characterization of the mineral to ascertaining the specific gravity and an estimation of the base and the acids. The following results were obtained: Specie eR ales x sachs oo 91554 eeelemttemee 3.160 iz bY Per Cent. — Per Cent. Siulheae:’ trans ois 5 .s.0'ai0-0 sete on ieee 16.32 16.63 Arsenic anhydride (i055 iss own veuins 2.31 2.40 COMES GRIME Susie cise Sas ss cw nl ven 68.90 68.68 Sita TEER So a hoe oe eo 1.63 1.18 If we deduct the quartz from the substance taken for analysis, the percentages of sulphur trioxide and oxide of copper will be found to approach very nearly to those in brochantite which contains: Per Cent, Sulphur trioxide sd: haces ves hes eehersile ets 197 COPTIC ORIGE SH h.caw Pe eee ab av eee eR ote 70.3 Water \issnccs gies kolo neta aueunen Ie aend ite able contol tae 12.0 and it is difficult to explain the rdle of the arsenic acid which is equivalent to about 4.4 per cent. of sulphur trioxide. To establish a definite formula for the compound it would be necessary to ascer- tain by further analyses whether or not the proportion of arsenic anhydride is constant, and to complete the analysis by an exact deter- mination of the water. The specimens in my possession, unfor- tunately, are not sufficient for this purpose. The specimens were collected at Copaquire, Province of Tarapaca. ATACAMITE. In conclusion I desire to call attention to some magnificent speci- mens of atacamite from Paposo in the Province of Antofagasta. They do not show the usual slender prisms, but consist of aggre- gates of fairly large crystals, closely resembling the octahedron of the isometric system modified by the cube and the rhombic dodeca- hedron. On closer examination, however, it would seem that they are really combinations such as have been observed on the atacamite 1908, ] KELLER—NOTES ON CHILEAN COPPER MINERALS. 85 Fic. 1. Atacamite from Paposo, Chile. from certain localities in South Australia.t As was to be expected, the analysis showed the specimens to be an atacamite of unusual purity and of normal composition. It yielded: MR Sus D Seg it ills akan ees a4 84 Sine bay 1 2 Calculated for Found. CuCl,.3Cu(OH).. Per Cent. Per Cent. CR isi sts ric to bw cin a xioa hota c hae vas RE 16.6 RGR ca cies Ghee eed ke Cree ih eaa ts to ee 14.9 Capric oxide. .aies Ue bib eke des he er ae 55.8 Wate. ec. rab ee eee eee papa teen beans eae 12.7 Prise (is, os%. bark eee cea ve ed iL etapa aia a 99.79 100.0 CENTRAL HicH SCHOOL, PHILADELPHIA, “I hope to verify this by actual measurement. PROGRESS OF THE DEMARCATION OF THE ALASKA BOUNDARY. By O. H. TITTMANN, U, S. CoMMISSIONER. (Read April 24, 1908.) The boundary between the British and Russian possessions in North America was defined by the Treaty of St. Petersburg of 1825. When the United States purchased the Russian possessions, or Alaska, in 1867, it was believed that the territorial jurisdiction of the United States and Great Britain could not become a matter of controversy. This view is evidenced by the remark made by Charles Sumner in his speech advocating the purchase of Alaska. “T am glad,” said he, “to begin with what is clear and beyond ques- tion. I refer to the boundaries fixed by the treaty.” The total length of the boundary referred to by Mr. Sumner is twelve hundred miles. It divides itself naturally into two sections of about six hundred miles each. One is the section bounded by the I4Ist meridian, and the other the irregular boundary delimiting the narrow coast strip of southeastern Alaska. No dispute has ever arisen as to that part of the boundary defined as being the 141Ist meridian of longitude west of Greenwich. As is well known, how- ever, a contention arose as to that part of the boundary which delimits the stretch of coast extending from the neighborhood of Mt. St. Elias southeasterly to and through the Portland Canal. A modus vivendi in 1878, affecting the Stikine River, and another in 1899, relating to the country at the head of Lynn Canal, made tem- porary provision for customs and police purposes. The dispute relating to that part of the boundary was happily settled by the Tri- bunal of London which was constituted under a convention signed at Washington January 24, 1903. 86 1908. ] OF THE ALASKA BOUNDARY. 87 Hon. John W. Foster, the agent of the United States in this important case, remarks in his report to Secretary Hay: “Tt is a noteworthy fact that this important adjudication was brought to a close within less than eight months from the time when the treaty creating the tribunal went into effect. Such a prompt result is almost without parallel in the intercourse of nations.” Equally prompt was the action of the governments in appointing commissioners in accordance with a requirement of the convention constituting the Tribunal. Within a few months, that is, in the spring of 1904, the commissioners, Mr. W. F. King, on behalf of the British Government, and your speaker, representing the United States, began the delimitation of that part of the boundary which had been in dispute. The commissioners were guided in their plans by maps, accompanying the decision, on which the Tribunal had marked certain mountain peaks as being the mountains contemplated by the Treaty of 1825. It is the business of the commissioners to identify the peaks, to establish their geographical position, to mark by visible monuments, wherever possible, the turning points in the line and such other points as may be necessary, and to describe and define the line between the points selected by the Tribunal. There was a stretch of about one hundred and twenty miles where the topographic infor- mation was insufficient, and there the commissioners were directed to make additional surveys and to select mountain peaks within cer- tain prescribed limits to define the boundary. The commissioners decided to mark at once certain river crossings and the mountain passes and to connect all the boundary peaks by a continuous triangu- lation based on the trigonometric datum adopted by the Coast and Geodetic Survey for southeastern Alaska. The boundary line, starting from the neighborhood of Mt. St. Elias, crosses that summit and other high peaks of the St. Elias Alps and the Fairweather Range. In general, it lies amid perpetual snow and ice except when it drops abruptly into the river valleys only to rise again into regions of perpetual snow. Finally, it reaches the head of Portland Canal and becomes a water boundary. In the four years since work was begun on this portion of the boundary the commissioners have fixed trigonometrically all the peaks 88 TITTMANN—PROGRESS OF THE DEMARCATION [April 24, except two near Mt. St. Elias and those in the region between the Whiting River and Devil’s Thumb, and some of the peaks south of the Unuk River. The passes, valleys and river crossings have been monumented with the exception of the crossing’ of the Alsek in the north and the valleys of the affluents of the Iskut and the crossing of the Le Duc and Chicamin rivers in the south. The turning points of the water boundary in Portland Canal also remain to be fixed by reference to points on shore. THE 141StT MERIDIAN. According to the Treaty of 1825 the 141st meridian west of Greenwich forms the eastern boundary of Alaska from the Arctic Ocean to near Mt. St. Elias. It was not until 1889—twenty-two years after the acquisition of Alaska—that any steps were taken by our government towards establishing the location of the 14Ist meridian on the ground. In that year the Coast and Geodetic Sur- vey despatched one party to the Yukon and another to the Porcupine River to determine the boundary crossing of those rivers. The Canadian government had previously sent an engineer to the Yukon who made an astronomical determination of the boundary in the autumn and winter of 1887. The country at that time was very inaccessible and the surveyors were compelled to determine the longitude by moon culminations and occultations, and the American parties spent a whole winter in observing them. But the operations of the three parties were not carried on under an international agree- ment and the results therefore were not reciprocally binding on the governments concerned. | The discovery of gold and the general development of the coun- — try, however, caused the construction of a Canadian telegraph line overland to Dawson and beyond, and later the United States govern- ment laid a cable from Seattle to Sitka and thence to Valdez on Prince William Sound, whence an overland line was built by the United States War Department as far as.Fort Egbert on the Yukon near the boundary. Egbert and Dawson were also connected by telegraph. This important auxiliary to longitude determination made it possible for the two governments to determine the position of the 141st meridian with all the necessary accuracy as soon as an 1908.] OF THE ALASKA BOUNDARY. 89 agreement was reached and embodied in the treaty signed at Wash- ington in August, 1906. This treaty provided for the survey and demarcation of the line and before the end of that summer the tele- graphic determination of the Yukon River crossing of the 141st meridian had been completed. The telegraphic determination made by the Americans rests on the known longitude of Seattle. Signals were exchanged between Sitka and Seattle, Seattle and Valdez, Valdez and Fort Egbert, Fort Egbert and the boundary. That made by the Canadians rests on the longitude of Vancouver between which place and the boundary time signals were exchanged. As the differ- ence between Seattle and Vancouver was also determined by the commissioners, the circuit was closed and a very satisfactory agree- ment was obtained. It is worthy of remark in passing that the tracing of a meridian or parallel on the ground involves considerations which do not become apparent by an inspection of an artificial globe on which these lines are traced as smooth and regular curves. A parallel of latitude must be determined by astronomical observations, but in general the circumference of a small circle of the earth parallel to the equator will not lie in the same astronomical latitude, owing to the so-called deflection of the vertical. A series of points deter- mined astronomically as being in the same latitude or, .as in the case of a meridian, in the same longitude, will therefore in general pro- duce on the surface of the earth a zig-zag line when they have been joined together. In order to avoid all questions that might arise from local deflec- tions of the zenith, it was provided by the Treaty of 1906 that the commissioners should determine by the telegraphic method a con- venient point on the 141st meridian and then trace a north and south line passing through the point thus ascertained. This provision fixed the telegraph crossing of the boundary as the initial point for the longitude determination. The commissioners desired to make the determination as nearly on the 1r41st meridian as possible, in order to avoid a deflection error which might have been involved if the longitude had been obtained by linear measurement from a lon- gitude observed at some distance from the boundary. The transit pier erected for the purpose of exchanging time signals was found 90 TITTMANN—PROGRESS OF THE DEMARCATION [April 24, to be in longitude 141° 00’ 00.4, a very close hit. It is interesting to note also that the final longitude differed only 9’’.43 of an arc, or 410 feet, from that derived by moon culminations about twenty years before. The work of tracing the boundary southward from the Yukon was begun in the spring of 1907 and was carried southward a dis- tance of about one hundred and twenty miles. Aluminum-bronze monuments were erected on the north and south banks of the river, a trigonometric and topographic survey was made extending two miles on each side of the boundary for a distance of about forty-five miles, and a broad vista was cut through the woods for the same distance. The work planned for the coming season will carry the tracing of the line as far as the great mountains south of the White River, and the topographic survey and the monumenting will be pushed until the severity of the weather compels the surveyors to abandon the work and turn their faces homeward. *% ‘ THE MOST PRIMITIVE LIVING REPRESENTATIVE OF THE ANCESTORS OF THE PLANT KINGDOM. By GEORGE T. MOORE, Pu.D. (Read April 25, 1908.) There is but little doubt among botanists that the land flora as it now exists has originated from aquatic ancestors. Both from the morphologic and palezontologic standpoints the evidence corroborates this view. Indeed, the dependence of land plants upon an adequate water supply, together with the fact that in such groups as the Mosses and Ferns, fertilization itself can only be accomplished in the presence of water supplied from some external source, gave rise to the conclusion that the origin of the vegetable kingdom was from primitive plants living in the water, long before there was the more conclusive evidence now existing. It would be interesting to inquire into the life histories of certain transitional groups with a view to tracing this migration from water to land. For modern morphological and physiological investigations has enabled us to do this with a considerable degree of certainty. Not only would we be able to show that the establishment of the higher representatives of our land flora had been brought about by certain methods of specialization in lower aquatic or semi-aquatic forms, but it would be possible to indicate to a certain extent at least how this process had been carried on. However such an inquiry would lead us entirely too far afield at this time and it will be necessary to grant without further discussion that the facts are sufficient to sustain the aquatic origin of the higher plants. Naturally, in seeking for the primitive ancestors of the vegetable kingdom, attention is at once directed to the alge, the group of plants which to a very considerable extent is more dependant upon the presence of external water for the carrying on of its vital processes than any other. Furthermore, in the present state of our knowledge, such an investigation would not be devoted to the more 91 92 MOORE—MOST PRIMITIVE LIVING REPRESENTATIVE [april 24, highly differentiated brown or red algze, but rather to the green alge, in which group there exists the closest resemblances to the structure of the lower land plants. The problem thus becomes one of discoy- ering as nearly as may be possible the most primitive member of the green alge. And by “ primitive,” of course, is not necessarily meant the simplest form, but that plant which seems to be nearest to the starting point of the phylogenetic tree and from which certain defi- nite lines of ascent can be traced. In considering the origin of the green algze, numerous theories have been held and it would be impossible to give even a mere outline of the various improbable suggestions which have been advanced regarding the evolution of this group. During the past ten years, however, a great deal of light has been thrown upon the phylogenetic relationship of the algze. Not only has the increase in our knowledge of the life’ histories of the alge been considerable, but the discovery of many new genera and species has made clear the affinities of various families as never before. Of the 275 good genera now recognized among the green algz, one fourth have been discovered and described since the appearance of Engler and Prantl’s “ Pflanzenfamilien ”—the last complete work on the subject and still the recognized authority. The addition of so many new and in many cases important links to the chain of development of these plants, has reduced the former chaotic condition to something like order and it is no longer quite such a matter of speculation regard- ing the origin of the main group of the green alge. Ten years ago Chodat derived the green algze from the simplest, unicellular, non-motile forms then known, namely, the Palmellacez. Within this family he included four genera whose simple life his- tory showed three principal stages. From these so-called “ condi- tions,” as Chodat pointed out, developed the three important and ruling tendencies which have dominated the lower green alge. These are: (1) The zodspore condition, or the unicellular motile stage, with the other two conditions transient or subordinate. (2) The sporangium condition, that is, the unicellular non-motile stage, with the other two conditions accidental or transient. (3) The tetraspora condition, where the non-motile cells are connected at right angles by the increasing consistency of the walls, giving rise 1908. ] OF THE ANCESTORS OF THE PLANT KINGDOM. 93 to the formation of a tissue or filament. The other two conditions are reduced or transient. Having established these three principal ‘“ conditions,” Chodat proceeded to establish the phylogeny of the green algz along these lines and succeeded in clearing up considerable obscurity which had previously existed. However, the starting point selected by Chodat has been open to some criticism and it remained for Blackman to suggest the most satisfactory explanation of the origin of this group. He, while following in a general way the theory of Chodat, took the position that the three “tendencies” had their origin not in the non-moile Palmella form, but in the motile Chlamydomonas type. I have had the genus Chlamydomonas under investigation for several years, observing its various species for the most part in pure cultures grown upon both solid and liquid media. The vegetative cells of Chlamydomonas are variable in both size and shape; in gen- eral, however, they are from 20-35, in length and 10-20,» in breadth, being elliptic or pyriform in outline. One end of the cell is usually produced into a colorless beak, from which two cilia always protrude. The chloroplast is quite variable in form and with one exception is provided with a single pyrenoid. Non-sexual reproduction is by means of zodspores, which are formed by the division of the contents of the mother cell, after it has come to rest. Sexual reproduction is usually by the conjugation of naked motile gametes of similar size and in no way distinguishable from each other. It is interesting to note, however, that in addition to this method there may also be the conjugation of unequal motile gametes and in one species—to be referred to later—there takes place the conjugation of dissimilar gametes, one of which, the larger, comes to rest before conjugation. We thus have within the limits of this well defined and natural genus, not only the most primitive form of gamogenesis, but through anisogamous conjugation a gradual approach to true odgamy—the highest type of sexual reproduction developed among the alge. In abandoning the starting point of Chodat’s theory of the devel- opment of the green algz, it is not necessary to replace his idea relative to the three predominating tendencies manifest in the lower members of this group. While different names are attached to these 94 MOORE—MOST PRIMITIVE LIVING REPRESENTATIVE [April 24, conditions as recognized at the present time, they are essentially those pointed out by Chodat, namely: 1. A tendency towards the aggregation of motile vegetative cells, with a gradually larger and more specialized motile colony. This is the Volvox type and in no place in the plant kingdom do we have a more perfect series of development than from the simple Chlamy- domonas form to the complex and highly differentiated V olvox type. 2. A tendency towards the formation of an aggregation of non- motile cells into a filament or tissue by the repeated vegetative division of an original mother cell. This is the Tetraspora type. 3. The Endosphera type, where the tendency towards the forma- tion of vegetative divisions and septate cell formation is reduced to a minimum. This is, of course, Chodat’s sporangiwm tendency, although not so much importance is attached to it. Without going into details it may be said that various species of Chlamydomonas (of which there are about thirty, all remarkably constant as regards their cytological characters), taken collectively, exhibit all these three tendencies and that the simpler forms of algz which possess but a single tendency, seem clearly to have diverged from some one species of this genus. The endospherine tendency in Chlamydomonas has given rise to a single family, Endosphera. ‘This is naturally strictly unicel- lular and with no vegetative divisions; the reproduction of the species can take place only by the formation of zoOspores or gametes. A family so restricted as to its vegetative habit could hardly be expected to develop very far and it is interesting to note that prac- tically all the genera are epiphytic upon other alge or aquatic plants, and that this habit of life has undoubtedly given rise to a distinct group of fungi. The suggestion has been made that the peculiar Siphonales may have developed from this Endosphera type, and while such a view is reasonable, it must necessarily, at the present time, be a mere matter of speculation. But one family, the Volvocacez, has resulted from the develop- ment of the volvocine tendency. While the evolution of sex in this group has been carried to the highest possible degree, the restric- tions of an enforced motile vegetative condition did not permit this family to give rise to anything further. 1908. ] OF THE ANCESTORS.OF THE PLANT KINGDOM, 95 It is the tetrasporine tendency which has been the permanent one and has resulted in producing the higher green plants. This condi- tion in Chlamydomonas resulted in the production of a series of plants which gradually replaced the formation of zodspores by that of vegetative cell division. The resulting family was the Palmel- laceze, the one which formed the starting point in the development of the algze, according to Chodat. While there seems to be but little question that the Palmellaceze have given rise to most of the other families of the green algz, there is every evidence that it was itself derived from Chlamydomonas, rather than the reverse, as contended by Chodat. It is impossible at this time to even indicate the development of the higher algz from the Palmellacez. With the exception of the Confervales, which seems to have developed independently of the typical green alge, and the Conjugales, which apparently have arisen directly from the Chlamydomonas type, all the higher green algz can be traced back through the Palmellaceze with considerable cer- tainty to their Chalmydomonas ancestor. The Conjugales have always been a stumbling block in constructing any developmental line of the alge from primitive forms. But granting that the fila- mentous Conjugales, as well as the desmids, are unicellular (the reasons for which can not now be given) it is comparatively easy to find the origin of the conjugation habit so emphasized in this group, in Chlamydomonas Braumit. In this species the female or receptive cell comes absolutely to rest before fertilization and the smaller or male cell becomes attached to it. Then the entire con- tents of the male cell passes into the female cell, leaving behind the empty cell wall, just as in some of the desmids and in most of the filamentous-like Conjugales. The more the genus is studied the more reasonable becomes the conclusion that Chlamydomonas has not only given rise to such an aberrent group as the Conjugales, but that it may safely be regarded as the phylogenetic starting point of the various lines of ascent in the true green alge. At present in the higher alge the Chlamy- domonas stage is, of course, retained in the zodspore and the gamete, a vegetative non-motile generation being interpolated between either PROC. AMER. PHIL, SOC. XLVII. 188 G, PRINTED JULY II, 1908. 96 | MOORE—MOST PRIMITIVE LIVING REPRESENTATIVE [April 24, a sexual or non-sexual motile stage. In the very highest type of reproduction in the green alge the male gamete alone represents the Chlamydomonas stage. Indeed, we may well assume that the motile male gamete of the mosses and ferns constitutes the last remaining type of the original Chlamydomonas condition, which with other more positive evidence points to the origin of such land forms from a Chlamydomonas-like ancestor. Although practically all the evidence for the position taken has necessarily been omitted, it is hoped that enough has been said to at least indicate the unique and important position occupied in the plant kingdom by the alga Chlamydomonas. THE COMPARATIVE LEAF STRUCTURE OF THE SAND DUNE PLANTS OF BERMUDA. (With 3 plates.) By JOHN W. HARSHBERGER, Px.D. (Read April 24, 1908.) The writer has discussed the flora of Bermuda in two papers pub- lished in the Proceedings of the Academy of Natural Sciences of Philadelphia and entitled “The Plant Formations of the Bermuda Islands ” (1905: 695-700) and “ The Hour-glass Stems of the Ber- muda Palmetto” (1905: 701-704). The study of the flora pre- sented in these papers and the study of the microscopic anatomy of the leaves of the sand dune plants herewith given is the result of a visit to the islands during the month of June, 1905. The sand beaches and sand dunes are found typically developed along the south shore of the main island and in a few isolated places on the north shore, as at Shelly Bay. The largest sand beaches and sand dunes on the south shore are found in the vicinity of Tucker- town Bay, on the narrow strip of south shore between Harrington Sound and the ocean. The sand dunes along the south shore in the parish of Paget are also characteristic. The sand dunes, how- ever, in the neighborhood of Tuckertown Bay are remarkable in that they have encroached on the rocky shore line and have invaded the natural arch which is one of the scenic wonders of the islands. The sand has drifted beneath the arch and has advanced so that it covers part of the top of the arch itself. The vegetation of the beaches and dunes here and in the vicinage of the Devil’s Hole is characteristically Bermudian, while the sand dunes in Paget have been colonized in part by plants introduced by man into the islands, such as the oleander, Nerium oleander, and a tall fennel, Faniculum vulgare. These beaches and dunes are formed of coral sand which represents the finely ground masses of 97 98 HARSHBERGER—COMPARATIVE LEAF STRUCTURE [April 24, coral and coralline (calcareous) sea-weeds which have grown on the fringing coral reefs. Bermuda, geologically speaking, is an atoll, a ring of coral reefs surrounding a central lagoon. The elevated land was formed by the raising of the weather edge of the reef above the level of the sea. The tops of the projecting corals were broken off and along with calcareous sea-weeds and mollusk shells were ground by surf action into a fine sand, which was formed into a beach. As the top of the beach dried in the sun, the sand was blown off and was deposited in the crevices of the coral breakwater, which gradually widened. Ultimately, by wind action, sand hills were formed. The limestone rock found throughout the islands was origi- nally derived from broken-down coral and shells. These rocks vary in texture from loose sand to compact limestone. The process by which the coral sand was converted into limestone was very simple and it involved no great lapse of time. As the sand consists almost entirely of calcium carbonate, it was easily soluble in water contain- ing carbon dioxide. The rain water took up a little of the calcium carbonate in the form of bicarbonate, and as it percolated through the sand, it lost its carbonic acid gas and evaporating left the dis- solved calcium carbonate as a thin layer of cement uniting together the grains of sand. The rocks remain permeable to water and soluble, so that this process of solution and deposition goes on con- stantly until even a marble-like limestone may result. The usual building material consists of blocks of limestone sawed out of the hillside. When built as a wall sufficient solution takes place so that the stones become united together into an almost solid piece. The red soils of the islands represent the one per cent. residue of solid material after the rain has leached out all of the other con- stituents. When the solution, owing to wave action or constant rain action, is excessive, caverns with stalactites and sinks are formed. The honey-combed eolian rock of the shore line on which charac- teristic Bermuda plants occur owed its origin to similar water erosion. The sand dunes thus represent stages intermediate in the geologic changes which have combined to give the present form to the islands. They represent shifting masses of coral sand, forming flat surfaces in some places, in other places heaped into conical dunes or raised into long ridges. Frequently dune hollows exist as a result of wind 1908. ] OF THE SAND DUNE PLANTS OF BERMUDA. 99 action in scooping out the sand. These dunes form the setting upon which the typical sand strand plants are distributed. PLANT DistRIBUTION.—The upper beach at the foot of the dunes is characterized by the presence of Cakile equalis, which shows a more decided branching habit than the closely related species on the coasts of the American continent, Cakile maritima. Besides this plant, the botanist sees clumps of Tournefortia gnaphalodes, Scevola Plumiert and Croton maritimus. The shrubs, however, grow most luxuriantly on the slopes and summits of the dunes. I[pomea pes- capre, as elsewhere in the tropics (Mexico, the West Indies), is a typical plant of the upper beach; in fact, the upper beach is char- acterized by its presence, with its long runners growing down from the slopes of the dunes out upon the flat, sandy beaches. On the dune slopes in Bermuda it is associated with Scevola Plumieri and the crab grass, Stenotaphrum americanum. Back of the dune crests are found Tournefortia gnaphalodes, Ipomea pes-capre, Scevola Plumiert, Juniperus bermudiana (wind- swept forms), Sisyrinchium bermudianum, Lepidium virginicum, Euphorbia buxtfolia (a prostrate plant growing in rosettes), Cana- valia obtusifolia (a leguminous vine) and the prickly pear cactus, Opuntia vulgaris. On the dunes at Tuckertown, where the sand covers the entrance to the natural arch, Scevola Plumieri forms extensive clumps in pure association. Solidago sempervirens, as in the eastern United States, is also a dune plant,.together with the smooth and hairy forms of Borrichia arborescens, Dodonea viscosa, a small tree with its varnished leaves, is also a tenant of the dunes. The most interesting dune plant is Conocarpus erectus, which is a typical mangrove tree growing with its roots affected by salt water. In Bermuda, however, it occurs perhaps more frequently on the dry upper slopes of the dunes. In one place on the south shore, it covers nearly a quarter of an acre. The crab grass, Stenotaphrum ameri- canum forms close mats on the lee side of the dunes. The high dunes on the south shore of the parish of Paget have been invaded by a number of exotic plants, introduced by man into the islands, such as Nerium :oleander, Lantana camara, L. crocea, while Croton maritimus, Canavalia obtustfolia, Dodonea viscosa, Borrichia arborescens and Passiflora suberosa are among the most 100 HARSHBERGER—COMPARATIVE, LEAF STRUCTURE April 24, abundant native plants. Yucca aloifolia forms clumps on low sand dunes at Shelly Bay, on the north shore, associated with Ipomea pes- capre, Tournefortia gnaphalodes and. Opuntia sp. Ecotocic Factors.—The ecologic factors, which have influenced the distribution of the typical sand strand plants of Bermuda, must be referred to briefly. As the plants of the Bermuda sand beaches and sand dunes in general show xerophytic adaptations, we must look upon these adaptive arrangements as a response to the environ- ment. The following environmental factors must be considered as influential in producing the xerophytic structures which the leaves of the Bermuda beach and dune plants especially show: 1. The intense illumination from above is an important ecologic factor. 2. The reflection of light from the white coral sand and the foam-crested breakers beyond is important. 3. The action of the strong winds that blow across the islands must be considered as modifying plant structure. 4. The action of the salt spray blown inland by the wind is marked in the case of some plants. : 5. The permeability of the sand to water, so that after a rain the surface layers quickly dry out, has its influence. The most potent factor in the modification of leaf structure has been undoubtedly the bright illumination from above and below (by reflection) and the physiologically dry condition of the soil. STRUCTURAL ADAPTATIONS.—The leaf adaptations to light are found in the increased number of palisade layers, their presence on the upper and under sides of the leaves, and their arrangement, so that the central part of the leaf becomes palisade tissue throughout, a typical staurophyll. The depression of the stomata below the sur- face, as in Sisyrinchium bermudianum, the distribution of the stomata in pits, as in Nerium oleander and Lantana involucrata, the develop- ment of hairs as in Tournefortia gnaphalodes, the varnished leaves of Dodonea viscosa and thick epidermal layers and cuticle are all arrangements to reduce transpiration. The succulency of the leaves of some of the dune plants is developed perhaps for water storage and the presence of latex should be mentioned as a means by which 1908.] OF THE SAND DUNE PLANTS OF BERMUDA. 101 a dune plant is protected against the untoward influences of its environment. Light has been most marked in influencing the development of leaf structure displayed by the typical sand dune plants of Bermuda. The stimuli of light have called forth functional responses which have produced changes in form or structure of the leaves, or in both. The chlorenchyma, composed of chloroplast-bearing cells, is con- verted into two kinds of tissues, palisade and spongy parenchyma, as a direct result of the unequal illumination of the leaf surfaces. Palisade tissue is formed as a response to light, or to low water content, or to both. When both leaf surfaces are equally illumi- nated, the leaf may be termed isophotic, when unequally illuminated diphotic. Diphotic leaves which are unequally illuminated show a division into palisade and spongy parenchyma, and such leaves are called by Clements? diphotophylls. Isophotic leaves, equally illumi- nated on both surfaces have a more or less uniform chlorenchyma. Clements divides such leaves into three types: (1) The palisade leaf, or staurophyll in which the palisade tissue extends from the lower to the upper epidermis. (2) The diplophyll, or double leaf, where the intense light does not penetrate to the middle of the leaf. In consequence, the upper and lower palisade layers are separated by a central loose parenchyma, which is for water storage. (3) The spongophyll, in which the rounded, loose parenchyma cells fill the leaf without palisade tissue. The influence of the light and other environmental conditions on leaf structure is perhaps best shown in the thin and thick leaves of Conocarpus erectus produced on different parts of the same tree differently related to the incident rays of light. A detailed description of these structures for each plant will be given at the end of the paper. The following is a classification of different leaf structures and the plants which illustrate such adaptive arrangements : Thick Cuticle—Nerium oleander, Conocarpus erectus (thin leaf), Scevola Plumieri. _ Thick Epidermis—Canavalia obtusifolia, Dodonea viscosa, Sisy- rinchium bermudianum, Stenotaphrum americanum, Ipomea pes- 1Clements, F. E., “Research Methods in Ecology,” 138-145; “ Plant Physiology and Ecology,” 171-184. 102 HARSHBERGER—COMPARATIVE LEAF STRUCTURE [April 24, capre, Cakile equalis, Borrichia arborescens (smooth leaf), Croton maritimus. Two or Three Epidermal Layers.——Euphorbia buxifolia, Nerium oleander, Conocarpus erectus (thick leaf), Croton maritimus, Tour- nefortia gnaphalodes. Two or More Rows of Palisade Cells. —_Passiflora suberosa, Dodonea viscosa, Nerium oleander, Sesuvium portulacastrum, Cakile equalis, Conocarpus erectus (thin leaf and thick leaf), Scevola Plumieri, Borrichia arborescens (smooth and hairy leaves). Stomata Depressed.—Sisyrinchium bermudianum. Heliotropium curassavicum, Sesuvium. portulacastrum, Ipomea pes-capre, Cakile equalis, Conocarpus erectus (thick leaf), Scevola Plumiert, Borri- chia arborescens (smooth leaf). Stomata in Pits——Lantana involucrata, Nerium oleander. Succulent Leaf.—Sesuvium portulacastrum, Cakile equalis, Con- ocarpus erectus (thick leaf), Scevola Plumieri, Borrichia arbor- escens (smooth leaf). Hairy Leaf—Lantana involucrata, Nerium oleander, Borrichia arborescens (hairy leaf), Croton PRR ONES, Tournefortia gnapha- lodes. Varnished Leaf—Dodonea viscosa. Leaf Becoming Erect in Sun Position. —Canavalia obtustfolia, Sisyrinchium bermudianum, Stenotaphrum americanum, Ipomea pes- capre. Overlapping Leaves.—Euphorbia buxifolia, Sisyrinchium bermu- dianum, Stenotaphrum americanum. Latex Tissue——Euphorbia buxifolia. Gum-Resin.—Cénocarpus erectus. Crystals—Passiflora suberosa, Croton maritimus. Diphotophyll.—Passiflora suberosa, Canavalia obtustfolia, Eu- phorbia buxifolia, Lantana involucrata, Nerwm oleander = 5. Diplophyll—Dodonea viscosa, Sesuvium portulacastrum, Ipomea pes-capre, Cakile equalis, Conocarpus erectus (thin leaf), Scevola Plumieri,? Borrichia arborescens (smooth and hairy womb Croton maritimus, Tournefortia gnaphalodes = 9. * Scevola Plumieri and Tournefortia gnaphalodes are given twice, because it is difficult to decide whether their leaves are diplophyll, or staurophyll. 1908] OF THE SAND DUNE PLANTS OF BERMUDA. 103 Staurophyll—Heliotropium curassavicum, Conocarpus erectus (thick leaf), Scevola Plumieri, Tournefortia gnaphalodes? = 4. Spongophyll._—Sisyrinchium bermudianum, Stenotaphrum ameri- canum==2. With reference to the last two plants, it should be mentioned that the leaves of these plants stand erect, thus receiving the incident rays of light on the edge of the leaf, hence the absence of palisade tissue and the presence of spongophyll structure. DETAILED STRUCTURE OF LEAvES.—The sections of the leaves which were studied were made free-hand with a razor. After stain- ing, the sections were mounted for permanency in Canada balsam. The drawings of these sections were made by the use of the micro- projection, electric lantern, so that in every case with the exception of Croton maritimus, the drawings were made on the same scale. The sketches of stomata are none of them drawn to the same scale. The description of the histologic structure of the leaves of each species follows. Passiflora suberosa is a small, slender species of the genus found growing over the sand surface of the dunes in the parish of Paget. Its flowers are small and the branch tendrils are characteristically developed. ‘Histologically the leaf presents an upper epidermis of large thin-walled cells, and as the whole plant is brilliantly illumi- nated, it has two well-marked layers of palisade cells. The loose parenchyma is narrow and some of the cells of it are filled with con- glomerate crystals. The stomata are slightly raised above the gen- eral epidermal surface, and are confined to the lower side of the leaf. A diphotophyll (Fig. 1, Plate IT.). Canavalia obtusifolia, a trailing leguminous plant, has paripinnate compound leaves with a long petiole and broadly elliptical leaflets with retuse apices and petiolules, a quarter of an inch long. The upper epidermis consists of slightly thickened cells. There are two rows of palisade cells, a considerable amount of loose parenchyma, while the slightly raised stomata are found on the upper and under sides. The adaptation to the environment of the sand dunes seems to be the folding together of the two sides of the leaves along the midrib, so that the edges of the leaves are presented to the incident rays of light. A diphotophyll (Fig. 2, Plate IT.). Euphorbia buxifolia is a prostrate, tufted plant of a rosette habit. 104 HARSHBERGER—COMPARATIVE LEAF STRUCTURE [April 24, The taproot is large and strong and from it numerous branches, six to eight inches long, are formed. The leaves are opposite, small, ovate, with an acute apex and barely petiolate. The upper epidermis consists of two rows of cells, the palisade is a single layer and the loose parenchyma is compact. The lower epidermal cells are papil- late and latex is present. The adaptation to the environment is shown in the latex, the two-layered upper epidermis and the over- lapping arrangement of the leaves. A diphotophyll (Fig. 3, Plate II.). - Dodonea viscosa.—This small sapindaceous tree occurs on the inner edges of the sand dunes. Its leaves are alternate, spatulate with the base narrowed to the point of attachment. The leaves are varnished. The upper epidermal cells are thick and provided with peltate hairs. The palisade cells are disposed in two layers. The loose parenchyma is open, while next to the lower epidermis there is a row of small cells which may be considered as a lower palisade layer. Hence the leaf is a potential diplophyll. The stomata of the upper side are slightly raised above the surface, while those on the under side have developed a small projecting beak (Fig. 4, Plate II.). Lantana involucrata is one of the plants that enters the formation of the Bermuda scrub. It also invades the dunes. The leaves are hairy on both surfaces. A section of a leaf shows that the upper ~ epidermis is without stomata, but is provided with straight, multi- cellular and capitate, unicellular hairs. The lower surface shows depressions provided with the capitate hairs, while the raised por- tions of the leaf surface between the depressions is covered with both straight, muticellular and capitate, unicellular hairs. The pali- sade is a single layer. The stomata project outward beyond the general surface of the lower epidermis, but they always occur in the depressions. The depressions provided with hairs and stomata and thick, hairy upper epidermal surface are structures which fit the plant to exist on the hot, sun-exposed sand dunes of the islands. A diphotophyll (Fig. 5, Plate IT.). Nerium oleander.—The leaf structure of the oleander, a native of the Mediterranean flora, is well known. The upper epidermis is in three layers with thick cuticle, the paliside tissue in two layers, while the under surface of the leaf is pitted, the pits being filled 1908.] OF THE SAND DUNE PLANTS OF BERMUDA. 105 with straight hairs that form an air-still chamber into which the projecting stomata open. The lower epidermis is two- to three- layered, and the whole leaf is decidedly tough and leathery, and thus well adapted to growing on the sand dunes of Bermuda. A dipho- tophyll (Fig. 6, Plate II.). Sisyrinchium bermudianum.—The Bermuda blue-eyed grass is provided with leaves that stand more or less upright, so that the inci- dent rays of light strike the edges of the leaves. The epidermal cells on both the upper and lower morphologic sides of the leaf are thick-walled and the stomata present on both surfaces are depressed the entire width of the epidermal cells. There is no palisade tissue, the loose parenchyma filling the center of the leaf between epidermal surfaces. The vertical leaves are, therefore, isophotic and the leaf is known as a spongophyll. The vertical leaves, the thick epidermal cells and the depressed stomata fit the plant to its environment. A spongophyll (Fig. 7, Plate II.). Stenotaphrum americanum. The Bermuda crab grass is a tough, wiry one, well fitted to survive in the driest places on sand dunes and rock faces. The leaf blades arise from sheaths that, together with other overlapping leaf sheaths, form a tuft that arises from the nodal regions of the wiry, prostrate, creeping stem. The blades are more or less erect and folded partially lengthwise, with the upper side innermost. The spike of closely set flowers is slightly bent, sug- gesting a crab’s claw. The upper epidermis consists of large, open papillate cells. The loose parenchyma fills the leaf section and the under surface of the leaf has a thick epidermis with numerous stomata, provided with small guard cells reénforced by two secon- dary cells. The bundles are toward the upper side. The vertical isophotic leaf consequently becomes a spongophyll. The adapta- tions to the environment are upright, rolled leaves, thick lower epi- dermis and overlapping, tufted leaf sheaths (Fig. 8, Plate II.). Heliotropium curassavicum resembles in its unilateral cymose inflorescence the common heliotrope. It is a slightly woody plant that grows about a foot or two tall, with alternate, narrow, oblanceo- late leaves. The cells of both the lower and upper epidermis are thin-walled, with slightly sunken stomata on both sides. The chlor- ophyll bearing cells of the leaf (the chlorenchyma) are arranged so 106 HARSHBERGER—COMPARATIVE LEAF STRUCTURE [April 24, that their long axes are placed in a line with the incident rays of light that strike the upper surface from above and the lower surface by reflection from the sand below. A _ staurophyll (Fig. 9, Plate IT.). Sesuvium portulacastrum.—The leaf structure of this member of the family Aizoacez is that of a typical diplophyll, but with a slight indication of the staurophyll arrangement of the cells. The stomata present on both sides of the leaf are slightly sunken and the guard cells incline inward and downwards. The upper and lower palisade tissues show four to five layers of cells. The leaves are thick and succulent. A diplophyll (Fig. 10, Plate II.). Ipomea pes-capre.—tThis tropical, seaside morning glory is a typical plant of the sandy beaches in Mexico, the West Indies and Bermuda. It grows down off the dune slopes onto the beach sand as a creeping plant, a distance of twenty to thirty feet (Fig. 1, Plate I.). The leaves are alternate, elliptical, retuse at the apex and frequently when the sun is hot and the reflection from the sand intense, the leaves fold together along the midrib and stand vertically so as to receive the incident rays of light on the upturned edges of the leaves. The walls of the epidermal cells on both sides of the leaf are thick. The stomata on both sides are sunken about half the thickness of the epidermal cells and the palisade tissue is promi- nent on both sides, constricting the loose parenchyma to a narrow layer. The leaf is, therefore, a true diplophyll (Fig. 11, Plate III.). Cakile @qualis——This cruciferous plant grows on open, sandy beaches in a more or less scattered manner. It branches in a much more open way than C. maritima, found in similar habitats on the sandy beaches of the eastern United States. The leaves are fleshy and the walls of the upper and lower epidermal cells are thickened. The stomata, which are partly sunken, are found on both the upper and the lower leaf surfaces. The palisade tissue on both sides is five layers of cells thick and the loose parenchyma is restricted to a narrow layer four cells thick in the central part of the leaf. This plant is fitted to its environment by the possession of succulent leaves, epidermal cells with thick walls, and many-layered palisade tissue. A diplophyll (Fig. 12, Plate III.). Contrast the leaf section of Cakile maritima (Fig. 12 A, Plate III.). 1908.] OF THE SAND DUNE PLANTS OF BERMUDA. 107 Conocarpus erectus.—The leaves of this small tree, which is a true mangrove plant, but which has adapted itself to growth on the sand dunes in Bermuda, are thin and thick. The thin leaves are found on the branches that are placed above the surface of the sand, or in more or less protected positions, while the thick, succulent leaves occur near the surface of the sand, or in exposed, unshaded positions. There is a considerable difference in the anatomical struc- ture. The cuticle in the thin leaf is thickened and the stomata on both sides are hardly if any sunken below the surface. The upper leaf surface shows long palisade cells, while the palisade cells of the lower side are shorter. The loose parenchyma cells form a broad band in the center of the section. A diplophyll (Fig. 13, Plate III.). The thick, succulent leaf has three rows of epidermal cells and three rows of palisade cells, the cavities of which are filled with a gummy, resinous material (not tested) of a brown color. This gummy material is found in the lower palisade as well as in the upper palisade in both the thin and thick leaves and also in some of the loose parenchyma cells of the thick leaf. The stomata in the thick leaves, by the increase in the thickness of the cuticle, are sunken below the surface with an hour-glass atrium or passage out- side of the thick-walled guard cells. The parenchyma cells of the leaf center are arranged in the direction of the palisade cells. A typical staurophyll (Fig. 13 A, Plate III.). Scevola Plumieri.—This plant belongs to the family Goodeniacez and forms dense clumps on the dune slopes (Fig. 2, Plate I.). Its leaves are alternate, elliptical, short petiolate and obtuse. They are noted for their succulency. The epidermal cells on the upper surface have a thick cuticle with numerous thick walled, sunken stomata. The epidermal cells on the lower surface are of the same thickness as on the upper surface, the stomata being likewise sunken. The palisade cells on the upper and lower sides consist in each of three or four rows of cells, while the loose parenchyma is arranged parallel to the palisade tissue. Only a single row of central cells are not so disposed. The leaf shows, therefore, partly a staurophyll and partly a diplophyll arrangement of cell (Fig. 14, Plate III.). Borrichia arborescens.—This species of the family Composite exists in two distinct forms, if they are not good species. One form 108 HARSHBERGER—COMPARATIVE LEAF STRUCTURE [April 24, has smooth, thick, succulent leaves, the other has thinner, densely tomentose leaves, the Borrichia frutescens of the Southern States. The succulent, smooth-leaved form has both thick upper and lower epidermal cells, with the stomata on both sides, but more plentiful on the lower side. The stomata are partly sunken. The palisade layers on both sides are wide, but are broken into more or less ex- tended patches by round parenchyma cells, which reach to the epi- dermis. The loose parenchyma cells form a wide central area. A diplophyll (Fig. 15, Plate III.). What the thin leaf lacks in suc- culency, it gains in hairiness. Both sides are densely covered with straight unicellular hairs. The palisade layers are only two in number on both sides of the leaf, and the loose parenchyma is also much reduced in amount. The succulency of the thick leaf fits it as perfectly as the hairiness of the thin leaf to the trying seaside environment, where the plants producing them grow side by side. A diplophyll (Fig. 15 A, Plate IIT.). Croton maritimus.—The leaves of this plant studied by Kearney*® are bifacial, both surfaces densely covered with gray scale-like pubes- cence, owing to presence of multicellular, stalked, stellate hairs that cover them. The upper and lower epidermal cells have thick walls and the stomata are not sunken. The palisade tissue in both the upper and the lower sides are two cell layers in width with a few sclerotic idioblasts. The leaf in the plant grown in the United States, as depicted by Kearney, has orily one row of palisade cells. Large conglomerate crystals of calcium oxalate are found in the cells of the loose parenchyma. Glandular capitate hairs are found on both leaf surfaces. A diplophyll (Fig. 16, Plate III.). Tournefortia gnaphalodes.—The leaves and stems of this plant, as well as the calices of the flowers, are covered with a dense, closely appressed, grayish tomentum, resembling that on our common An- tennaria plantaginifolia and edelweiss, Leontopodium alpinum. In section the hairs are unicellular, straight and of epidermal origin. The palisade is formed on the upper and lower leaf surfaces and is two cells thick. The loose parenchyma, occupying the center of the leaf, suggests an arrangement in direction parallel to the long axis * Kearney, Thomas H. “ Plants of Ocracoke Island,” Contributions from the United States National Herbarium V: 2096. 1908.] OF THE SAND DUNE PLANTS OF BERMUDA. 109 of the palisade cells. Therefore it is a diplophyll (Fig. 17, Plate III.). BIBLIOGRAPHY.—Little has been published on the structure of the dune plants of tropical America. The following papers are in part a contribution to our knowledge of the microscopic struc- ture of the strand plants of the American tropics. A few of the sand dune plants are of cosmopolitan distribution and they are; therefore, described as to their morphology in the classic: work of A. F. W. Schimper, “Die indo-malayische Strandflora,” pub- lished as the third volume of “ Botanische Mittheilungen aus den Tropen” in 1891. Thomas Kearney in 1900 published in the Con- tributions from the U. S. National Herbarium (V., No. 5) an important paper on “The Plant Covering of Ocracoke Island; A Study in the Ecology of the North Carolina Strand Vegetation.” 8", PM Lagrange’s theorem asserts that if s=vu-+ ro(2) F(2) =S0) + (0) F"(0) + = SHO /'@)} + (12) Si es al aot ail sit If now f(z) =2", (2) =— a and after the derivatives in series (12) have been formed v is replaced by —c/a, there results, making x unity, 2 Para ECS) estat teo(S (13) + spaplt + 3h— (1 + 3629) (— ‘ye b 1+4k + alate! 1+ 4k—n)(1+4k—2n)(1+4k—32) (- ‘yt In series (13) the law of formation of the successive terms is evident and this law is readily proved by induction by using La- grange’s theorem. Series (13) may be more concisely written by placing eve : (-;) =e so that y, is a root of the two-term equation 1908. ] IN INFINITE SERIES. 115 ay o” “| C= O, and denoting the continued product (1 + sk —n) (1 + sk — 2n) (1 + sk — 3n)--- [1 + 5k — (s—1)n] by I+sk—n | (14) are ; With these conventions series (13) becomes 2 b b : V=IN, + eg + Sade [1 + 2k — nyt B I+3k—2] 1.5, bt 1+4k—n] 4 (15) Oe Eater Sg val ool papel ee +.-- b° I+ sk—un ae Les, boot he roe If series (15) is convergent, it will furnish a root of the three- term equation ay" + by! + ¢—=0 ; for each one of the m values of Yo. 10. To test series (15) for convergency write the first terms in regular order in a row, underneath this row the succeeding terms and so on indefinitely. The terms of series (15) will now be arranged in ” columns as follows: Seen Seoeaene |= ass eaves, anita) al) a (rtm) few |] we2ust (us) xT Us)FT 7 ee {—us? u—y( I +us) ay 5 . z ; a : . w(1+-uz)—y(1-++az) a i(r+uz) re epee u( Sr eS few —ugtt j ai, es x1—wO +1 v a Pectent cs Cee Ae ee hua? rere | u—yue ty es es u( 1+) -- (1 +u)+1 w pute} ic +) qt — uPA oust je evant tea an teat. ape ert gf ef i xc—w) 1° (Sor | | eet Se er 4 (or) 1908. ] IN INFINITE SERIES. 117 This rearrangement of the terms of series (15) into the col- umns of the table is permissible, inasmuch as throughout this inves- tigation only absolute convergence is considered. Cauchy’s ratio test shows that each one of the partial series composed of the terms in each of the ” columns of the table is con- vergent when o” n" (17) akcr—* SFn ea ky 11. In like manner, if the algebraic functions defined by the equations (2) ay" ++ by! + cx =0 (3) ayrx + by" + ¢=0 are expanded into power series in x by Lagrange’s theorem, and if 4 is made unity in this power series, it is found that the resulting infinite series are convergent, provided o” n” (18) wink > En de ky 12. If condition (18) is satisfied, equation (2) determines n— k and equation (3) determines k roots of the three-term equation ay” + by* + c=0. Either condition (17) or condition (18) must be satisfied, unless b” n” (19) aéc’—* re k*(n aks ne If condition (19) is satisfied, Raabe’s test shows that the series obtained from equations (1), (2), (3) are all convergent. 13. The convergency conditions for equations (1), (2), (3) may be written by following these directions: (a) To the left of the sign of inequality stands a fraction whose numerator contains the coefficient of the middle term of the three- term equation ay" + by + c==0 and whose denominator contains the product of the coefficients of the end terms, the exponent of each coefficient being the difference of the exponents in the other two terms taken in order from left to right. 118 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS {April s, (b) The fraction to the right of the sign of inequality is obtained from the fraction to the left by replacing each coefficient by its exponent. (c) The sign of inequality is < when the term containing 4 is between the other two terms; if the term containing 4 is an end term the sign of inequality is >. 14. The following table exhibits the convergency conditions for the series obtained from equations (1), (2), (3) and the number of roots of the three-term equation ay" + by* + ¢=0 furnished by each one of these series. o” n" iat ek ts f . O* = Bn — B® (20) (2) ay" + by* “f CA =O i1— kR on i ” (3) ax + by +c=0 k act Rn — ky The roots of the three-term equation can always be expressed in infinite series. III. Tue Four-TerM EQuaATION. 15. In the four-term equation ay" + by" + cy! + d=0 the two terms from which the factor 4 is to be omitted can be selected in six different ways. This gives rise to the six equations: (21) ay” + bykx +: cy’ +d=o (22) ay” + by’ + cyl” + dx =0 (23) ay" + by" + cyl'x +d=0 (24) ay" + by" + cy! + dx=o0 (25) ay" + bykx + cy' + d=0 (26) ay" +- bykw + cy! + dxr=0 Each one of these six equations defines y as an algebraic func- - tion of x. The y of equation (21) may be expanded into a power series in x by any one of the three methods of articles 7, 8, 9. Using the symbol (14) and denoting (—d/a)/ by 4p, this power series, when + is made unity, becomes IN INFINITE SERIES. 119 1908. ] ruS—y$ + 1] ie ve Dot jS fe a EY Pett iS pol jS a «| |: nt «| oo-4 oF eho” | Figtaet1 u—j~+¥8 + I 276 Pita u—jp+yb+ S 2,95 Fatt é u—yS+1 J & = V—77 +477 +11,7,% iV uv—7+y¥F+1],p,u iP fuv—yV+11,p,% jv ae ‘«|* 7 | 5% | ‘c| Lid att AY ooo Fr +P” | Fiztaztt u—jet+yzt+i4 2,9b Fityet u—j+yS+14 296 Fy tt Lu—ybt+i] + E—77+Y+1] peu jE ul —7+49Y7Z +1], Pou j£ uf—yf+1 u je Pe va ie |: et j «| | got va | i Fistatr u—j~+y+i 229 Five tt u—1+9Z+1 ge Fast u—yE+1 & * ctr [uw =r 1] ers é - reat’ [M—7 +7 + ios = Fai [u —ye+ ere is: z . pu u Hf — + une - %¢ = (ZZ) 120 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS Aprils, _ 16. The infinite series composed of the terms of the left-hand column of the value of y is convergent when b” We n” (28) aid h(n Re cabal and if condition (28) is satisfied this infinite series furnishes the solution of the three-term equation (29) ay" + by* + d=0. It is found that each one of the infinite series composed of the terms of the respective columns of (27) is convergent when (28) is satisfied. It follows that (27) may be written c yo te (29) y= Xt Fa Iot + agate “a + Faso Ast where Xo, X,, X., X3, «++, stand for the sums of convergent series. If now X is the largest of the numbers X,, X,, X., Xz, °° si c e é (90) 9X (14 yl + ptt ppt), and this last value of y is convergent when € l (31) pa in convergency conditions corresponding to conditions (32) and (35) the right-hand member is the reciprocal of what it is when the sign of inequality is <. 20. In like manner two sets of conditions sufficient for the abso- lute convergence of the infinite series giving the roots of the four- term equation obtained from each one of the equations (21), (22), (23), (24), (25), (26) may be written. The convergency conditions for all these infinite series may be taken from the following table, in which the signs of equality of the limiting conditions of convergence have been omitted. gn nm gn—t ck (38) ee aie age (21) ayLoytxtoyetd=o| < < nn (22) ay"4oyk+cylxtdx—o| > > (n—2)e# (23) ay"x+ by*+-cyx+d=0 > < hk (24) ay®x+byk+cy'+dx—=o > (42> (25) ay"x+ bytx+cy!+d=0 i” > n (26) ay" bykx+ cyt deo df > (n—l)n* ne nn (m—/)r— hk kk(n—k)"—* Z'(n—l)n— (A—1)*""(n— hk) LY k—1 yet In this table the signs of the two inequalities which constitute the convergency conditions of the series obtained from the equa- tions (21) to (26) are placed to the right of the respective equations. The left-hand member of each inequality is at the top of the column ~ in which the sign of inequality stands. The right-hand member of one inequality must be taken at the bottom of the column in which the sign of inequality stands; the right-hand member of the second inequality is the expression at the right of the row in which the sign of inequality stands when the sign of inequality is <, when the sign of inequality is > the right-hand member of the inequality is the reciprocal of this expression. 21. The following table exhibits one set of convergency condi- tions of the infinite series which give the roots of the three-term equation ay" + byt + d=0 together with the equations from which these series are derived and 1908. ] IN INFINITE SERIES. 123 the number of the roots given by each series, and also the conditions sufficient for the absolute convergence of the series of corrections which must be applied to the roots of this three-term equation to obtain the roots of the four-term equation (39) ay” + by* + cy’ + d=0, b” c” or—! cP j a’d”™—* aa" a "cn—k b'd*—! I ay"+by*x+d=0)| n < < ni ay" +by*+dxr=0 |n—k > > ay"x+by*+d=0| k > n” I 22. The substitution 2", (40) where s is a positive integer, transforms the four-term equation ay” + by" + cy’ +-d=0 into the four-term equation ag"s +. bgks 1 cgls + do, The table of convergency conditions for equation (41) corre- sponding to table (39) is (41) (42) bn 8 cn 8 br—? 8 ck . fee) ae (335) ) I as"+bs"r%+d=0| us < < as” +62" +dx=0 ns—ks + + az“xt+bs"*+d=0| ks > < RBs Tei (aa) (s)" nash (SA) The three-term equations ay" + by* + d=0 ag"s +. bgks +.d==0 for all values of s have the same convergency conditions. 124 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS [April as, If the inequality c n a qr! (x hin ay Bd*— of table (39) are not satisfied simultaneously, it is always possible to take s sufficiently large so that the corresponding inequalities of table (42) oO n” gr I Pong ph a’*d”—* - k(n ay 2 ’ a on—k a s**(n pa ky" ’ b'd*— < s eg) x will be satisfied simultaneously. To the convergency conditions of table (42) must be added the limiting convergency conditions obtained by replacing in the first column of inequality signs of table (42) each inequality sign by the equality sign. It follows that it is always possible to determine s so that all the roots of the four-term equation (41) ag’ + bgks 4+ cgis + do may be derived from the roots of the three-term equation . (42) az"s +. bgks 1 d—=o, The roots of the four-term equation | ay" +- by* + cy’ + d==0 are found from the roots of equation (41) by substituting in (40) y= 2. 23. While table (42) shows the possibility of expressing all the 1908. | IN INFINITE SERIES. 125 roots of equation (41) in infinite series, the method of article (22) requires the determination of the us roots of equation (41) to find the m roots of the four-term equation ay" + by* + cy’ + d=0. This method is therefore to be avoided in practice when possible. The following table exhibits the conditions sufficient for the absolute convergence of the infinite series which give the roots of the four-term equation obtained from the four groups of equations. The series obtained from each group of equations determine all the roots of the four-term equation. The convergency conditions must be taken from this table as in article 20, and the limiting convergency conditions must be taken into account. A less inclusive set of conditions sufficient for the absolute con- vergence of the series which give the roots of the four-term equa- tion derived from the groups of equations of table (43) is obtained by taking the second member of each inequality from the bottom of the column in which the sign of inequality stands, on a bn—t ck (43) age «=| Gat Pe yr Fae Ll a+by'x+cyxtd=o| n < < n Il { ay” + by*§+-cy'x+dx—=0 |n—k po > (~—h)"-* ay"x-+-by'+cy'x+d=o| k > << Rk Il { ay" by*§x+ cy'+-dx==o |n—l aes & | (2—l)"— ay"x+byktx+cy'td=—o| 1 = a Zt ay"-+-byt+ cyxtdx=o|n—k| > ys (n—2) IV ay"x+ by*+-cy'+-dx=o |k—l > > (A—1)* ay x+bytxtcytd=o| 1 on - a ne n® (nx—l jr Bk R*(n—k)*—* 1" n—1) "1 (A—1)*-l( n—h)* 14 R—1) #4 It is only when the convergency conditions of the groups I, II, III, IV, together with the corresponding limiting convergency con- ditions fail simultaneously that the use of equation (41) becomes necessary. IV. THe FIve-TERM EQUATION. 24. In the five-term equation ay" + by* + cy? + dym + 1==0 126 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS [April as, the two terms from which the factor x is to be omitted can be selected in ten different ways. This gives rise to the ten equations: (44) ay" + byke + cyte + dymx + I=0 (45) ay" + byk + cite + dyma + lero (49) ay" + byte + cy! + dyma + r= (47) ay" + bykx + cyte + dy™ + lr=o (48) ayrx + by* + cy! + dyme + lo (49) aya + by* + cyte + dym + lr=0 (50) aytx + byte + cy! + dym + lr=0 (51) ayrx + by* + cyte + dymx + 1=0 (52) ay"x + byte + cy! + dymx + 1=0 (53) aynx + bykx + cy'x + dy™ + 1==0 Each one of these ten equations defines y as an algebraic func” tion of + which may be expanded into a power series by any one of the methods of articles 7, 8, 9. 25. The terms of the power series expressing the value of the algebraic function defined by equation (44), using the symbol (14) and placing y, = (—//a)*/, when x is made unity, may be arranged as follows: ye: IN INFINITE SERIES. 127 1908. | 0 ing = F tet & uf—u+jz+1 lta | £ ae 0 Fetaat a | uU—u+jZ+1 rs 7 pear ax hs ez if pee OU Lm tyty tid pat U,d |Z wiyey Ole —met y+ 1] . ae + eA ar ocpartrety tea 1 E 1 uU—JZ y+! 2798 1+4Z+1 u—j +42 +1 298 metlum—pet rete saya [wp tyr] MELE + rt = 7 & 2 tia | ut —u 442 + ‘1 glad E U—U+yz +1 pat wyty Luu by + 1] pel” EE pqe us ae § ? os S—yf 417 aif - ‘c|* 4 |: ef | ert a—zS +1 7) cg rot [u—ge +1] SEE + 2 ua att q rT % =< (¥$) + PROC, AMER. PHIL. SOC. XLVII. 188 I, PRINTED JULY 20, 1908. 128 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS _[Aprilos, 26. The first group of terms of (54) is the infinite series which gives the solution of the four-term equation ay" + byt + cy! +1—=0 obtained from the equation ay" + byte + cyte +1l=o provided the conditions oO” n” or atone Pin—ky*? aie <2", are satisfied. The second group of terms has the common factor d ct gy e eno? and the successive groups of terms respectively the common factors ‘ae 2m a? a@ 4m Ppt 4 Zpoo” , Ani , The convergency conditions of the successive groups of terms are identical with the convergency conditions of the first group. It follows that (54) may be written 2 3 a a ad (55) ip ra Soe nh + Yao” + Yan 3 Im eee, where Yo, Y,, Y., Ys, Y,, ---, represent the sums of convergent infinite series. If Y denotes the largest of the numbers Y or) has a? a® (56) ysv (1+ yp T 2 ape” + aI” +). The series (56) is convergent provided (57) Bele en If both members of the inequality (57) are affected by the exponent n, condition (57) becomes rics (58) yma — 2". ae ‘The conditions sufficient for the absolute convergence of (54) are therefore 1908. ] IN INFINITE SERIES. 129 n n n n nN c (59) wen a, En a4 Ry? ae <1, Fe <2”. 27. When the conditions (59) are satisfied the first group of terms of (54) gives the roots of the four-term equation ay” + by* + cy? + 1==0 expressed in the series obtained from the equation ay” + byte + cy'4 +10 and the successive groups of (54) are the series of corrections which must be applied to the roots of this four-term equation to obtain the roots of the five-term equation ay” +- by" + cy! + dy + l==0. 28. If in the first row of (54) either of the terms c ad ra 1+1 ip 1+m én Jo) en Jo is placed first and the consequent changes in (54) are made, the convergency conditions of the two new series are found to be o” i Fas n” a” Z (60) ake —* es, n , ae! an, L'(z Siok jr ’ ane—™ ed nN ’ gee Be at CAE n" I ee ae uN ss Se ET wh SE a . b aor S ’ ae ss ’ aner-™ em m"(n—m)"— In the limiting convergency conditions the signs of ineqtality in the first inequality of (59), in the second inequality of (60) and in the third inequality of (61) must be replaced by the equality sign. The conditions sufficient for the absolute convergence of (54) may be written from equation (44) by the method stated in article 19. In like manner the conditions sufficient for the absolute con- vergence of the series obtained from equations (45) to (53) may be written. The convergency conditions for all these series may be taken from the following table. The convergency conditions are taken from the table by the method stated in article 20, except that the right-hand members of two inequalities must be determined from 130 LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS [Aprilas, the expressions at the right of the row in which the sign of inequality stands. i 7 ‘ T T Die leiy lela le lf le lela ltl (62) fale lelb ele lER ITs laiblalt Lifts a) RISA] S/S le] sid eT 8 Be a Gag ges (Ep "nn (45) | > bee Tet (~—k)n—* (46) > act 2 (w—l)"+ (47) pe ae Bae < (u—m)"—™ (48) i EN > | (4) (49) > > < |(4—m)i-m (50) >l|> | >i ee (53) | > IN ER 8 hee (52) — ue <— i (53) > > > m™ Lit TENG T , < om Maat 2S is | eel Le el Bites] eh r § Pred fa a pe ~ i Pellet (L/TEITE (Ay i TESS ie yee) ot & ~~ ~~ ~ 29. The following table exhibits one set of conditions sufficient for the absolute convergence of the infinite series which give the roots of the four-term equation ay" + byt + cy! +1=0 | together with the equations from which these series are obtained and the number of roots given by each series, and also the conditions sufficient for the absolute convergence of the series of corrections which must be applied to the roots of this four-term equation to obtain the roots of the five-term equation ay" + by! + cyt + dym + 1=o. bn cn bn—l ck a” bn—m dk (63) ~ qgken—k | alen—1| ghk—len—k |blek—l\ qmen—m| ak—mgn—k | jmgk—m I ay*+tbytx+oy'x+e=—0| n — ee «K U ay" +-by*+ cy'x+-ex=o| n—k je > on aynx+-by*+cy'xt+e=0 & > < < nn I I PSR TEIN SATA ROM aaa ke pumas | B(n—kye—k| ™ | Game ‘ ” \(n—kynak it 1908.] IN INFINITE SERIES. 131 30. The substitution (64) y= 2, where s is a positive integer, transforms the five-term equation ay” + by" + cy’ + dym + l=0 into another five-term equation (65) ays + byks +. cyls + dyms + ]=—=0, An examination of the table of convergency conditiohs for equa- tion (65) corresponding to table (63), shows that it is always pos- sible so to determine s that the convergency conditions for the series obtained from the equation (66) ay"? + byksy 1 cylsy + dymex t+ J=0 or from the pair of equations (67) ay" + byk* + cyte + dymtx + lr =0 (68) ay"*x +. byks +. cylsy + dymsy + ]=0 are satisfied. Hence it is always possible to determine all the roots of a five-term equation by means of series. 31. The method of article 30 requires the determination of the ns roots of equation (65) in order to find the » roots of the five-term equation ay" + by* + cy! + dy + l=0. The use of this method becomes necessary only when the conver- gency conditions of the seven groups of equations of the following table, together with the corresponding limiting convergency condi- tions fail simultaneously. The convergency conditions must be taken from this table as in article 20. A less inclusive set of congruency conditions may be taken from this table as in article 23. [April 25, LAMBERT—SOLUTION OF ALGEBRAIC EQUATIONS 132 T | ala ell la ieleelal ja 2 Te bis] gd | Mel Me LBL ds Te] Us | Us als /8 ee TH | ae ed eg ee ete oe (eG x ee nea oe Sie eRe ieee Gina s: Sea Ae Pi ee ee ee I i yor wild < < < ut) |O= 2+ whp + Xl? + Kyhg + Kuo ag) << | ep u—z | 0 = x9 + hp + 2 + wyhQ -+ Kuh i -ali—¥) | < < < Py | O= K8 + Xyhp + A? + hg + Xho y—u(¥—#) ; Eee < | y—u |o= ma + wuhp + x62 + hq + who wuld < < < ue | O= 2 + hp + XY? + HylQ + Kalo u—(u@—7) | < < < mu—p |O= %a + Ap + flo + wyhg + xyAv IA 1-u( 7—*) < = < J—u |O= Ka + Hyp + lo + %ytg.+ who al > _# rd 7 |O=at Kup + fo + wylg + xo wx(7—-¥) | < noe oS 17 |O= Ka + Kulp + 9 + hg + Xyho . y—u(¥—2) = < < | y—u | o= Ka + Kup + 1h + yh9 + who wilt ct = < um |\o=atutp +r Spa re w—u (%a—2) : ee < m—u |O= xa + hp + x2 + xyh9 + wl al = < < 7 Sees Oe me 1-u( 7—#) << a a p—u |o= xa + xuhp + fo + x4h9 + who af a > —< y Pinetop Saree y—u(y—t) ae < | y—ulomxa + rwhp + 262 + yl + who ult Be. = > wu \o=xa+ tulp + xyo+ g+uwo | > ~) a, Q Q 8 3| ® 2 d aie =| 5 T = a es = ~ ~ 6 JT) y=] att 1° Wyld 1? wee (69) 1908. ] IN INFINITE SERIES, 133 V. CONCLUSION. 32. In the algebraic equation of ¢ terms f(y) =o the two terms from which the factor x is to be omitted can be selected in t(¢ — 1) 2 ways. Each one of the resulting equations defines y as an algebraic function of x, and each algebraic function of x can be expanded into a power series in x by the methods used to obtain the corre- sponding expansions for the three-, four- and five-term equations. When # is made unity in these power series the resulting series become the roots of the ¢-term equation and a table of convergency conditions for these series analogous to tables (20), (38), (62) can be set up. In fact, this table may be written mechanically by fol- lowing the directions of article 19. 33. If in the ¢-term equation the substitution yas is made, a table of convergency conditions analogous to tables (39), (63) can be set up, and the value of s can be determined so that this table of conditions shows that it is possible to obtain all the roots of the transformed equation from the series derived either from the equation in which # is omitted from the first and last terms, or from the two equations in which 4 is omitted from the first. and second, and from the second and last terms respectively. The roots of the given equation are then found from the roots of the transformed equation by substituting in y= 88, 34. Finally, tables of convergency conditions analogous to tables (43), (64)’ can be set up for the t-term equation, and it is necessary to use the transformed equation only when the convergency condi- 134 MINUTES. [May ts, tions of all the groups of this table, together with the corresponding limiting convergency conditions, fail simultaneously. 35. It follows that all the roots of an algebraic equation of any number of terms, that is, of any algebraic equation, can be expressed in infinite series by the method of this investigation. LeHicH UNIVERSITY, BETHLEHEM, PA.,; April 2, 1908. Stated Meeting May 1, 1908. Treasurer JAYNE in the Chair. Dr. Martin G. Brumbaugh, a newly elected member, was pre- sented to the chair, and took his seat in the Society. Letters were read, accepting election to membership from Martin Grove Brumbaugh, Ph.D., Philadelphia. Walter Bradford Cannon, A.M., M.D., Boston, Mass. James Christie, Philadelphia. Edward Washburn Hopkins, Ph.D., LL.D., New Haven, Conn. Josiah Royce, Ph.D., LL.D., Cambridge, Mass. Jacob G. Schurman, Ph.D., Ithaca, N. Y. Edward Anthony Spitzka, M.D., Philadelphia. Robert Williams Wood, Ph.D., Baltimore. Mr. R. H. MatHews presented some “ Notes on Australian Laws of Descent.” Professor Albert A. Michelson, of Chicago, was unanimously elected a Vice-President to fill the unexpired term of Professor George F. Barker, resigned. Stated Meeting May 15, 1908. Curator DooLiTtTLe in the Chair. Letters were read accepting membership from William Hallock, Ph.D., New York City. Leonard Pearson, M.D., Philadelphia. Charles Henry Smyth, Ph.D., Princeton, N. J. John Robert Sitlington Sterrett, Ph.D., Ithaca, N. Y: Ernest Nys, Brussels. 1908,] IN INFINITE SERIES. 135 From Professor Albert A. Michelson accepting election to the Vice-Presidency to fill an unexpired term. From the Committee of Organization of the Third Congrés International de Botanique, announcing that the Congress will be held at Brussels from May 14-22, 1910, and inviting the Society to be represented by delegates. Dr. H. M. CHance read a paper on “ The Origin of Bombshell Ore” (see page 135), which was discussed by Mr. Sanders, Mr. Jayne and Professor Doolittle. THE ORIGIN OF BOMBSHELL ORE. By H. M. CHANCE. (Read May 15, 1908.) The term “ bombshell” ore is applied by miners and iron-masters to hollow masses of limonite—brown hematite—which sometimes are round or oval but more commonly are of any irregular shape. The “bombs” may contain water, clay, sand, quartz, flint, pyrite, siderite, sandstone or decomposed slate, or may be entirely empty. Geolo- gists usually speak of such ore as nodular or concretionary. A careful examination of the literature of ore deposits and especially of that relating to the genesis of limonite ores fails to disclose a satisfactory explanation of its origin of mode of formation. By many it is assumed to be similar in origin to silicious geodes, which are supposed to be formed by the deposition of silica or silicates upon the walls of cavities, while others describe it as of “ concre- tionary” origin without attempting to explain the process of forma- tion or the manner in which it has occluded the variety of materials which are found in the interior of different specimens from the same locality. That it is not of concretionary origin is evident upon even cursory consideration, for concretions are masses of material ar- ranged in concentric layers around a central nucleus. The latter _ may be a grain of sand, a pebble, fossil, or any substance around which (as a core) the concretion forms, growing from the center by the successive addition of concentric rings. Concretions are perhaps merely symmetrical segregations. The peculiarities of this ore are well desinbed by Professor T. C. Hopkins, Bull. Geol. Soc. Am., 1890, Vol. 11, p. 477, etc., as follows: “Nodular ore consists of irregularly rounded masses, varying in size from a fraction of a pound to several hundred pounds in weight. The masses are frequently hollow, but some enclose a rounded or sub-angular rock fragment, which is sometimes sandstone, . .. sometimes chert, some- times ‘slate, and sometimes clay. Some shells are filled with clay and sand, 136 1908.] CHANCE—THE ORIGIN OF BOMBSHELL ORE. 137 and workmen report finding many of them filled with water. Some are filled with clay, which still retains the laminated structure and appearance of the original slate from which the clay was derived, furthermore, the slaty structure was found to extend through the ore shell, which showed, besides the plain lamination of slate, a faint concentric structure as well. . .. While only one shell was found still retaining the laminations of the clay, there were many others containing clay and sand. Some of the shells were but thin crusts, while others were quite thick, almost solid; some have a smooth, velvety or bright mammillated inner surface, frequently coated with manganese oxide. In some instances the lining of the shell is covered with many small stalactites of ore.... Many of the shells are lined with a dense fibrous layer, often an inch or more in thickness. ... The thinner shells have all been broken, and we see only the fragments of them in the clay-ore masses. This shell form of ore... forms an appreciable part of the ore body in many cases. The small, irregular, nodular-like«pieces of ore, commonly knows as shot ore, are presumably closely related in origin to the shells... .” The inner wall of many bombs consists of a hard, bright, brown or jet-black, glazed surface, curved, rounded or botryoidal. This is frequently described as a manganese coating, but is doubtless a film of iron or manganese silicate. Occasionally the interior or a part of the interior is lined with a layer of extremely hard, flinty, liver- colored iron silicate, or with quartz crystals or chalcedony, and the same silicate frequently forms a considerable portion of the body of the shell or of its outer layers, but generally the shell is composed of high-grade limonite, of a fibrous structure, especially in those layers forming the inner lining of the shell. These peculiarities are satisfactorily accounted for neither by the theory that these ore masses owe their origin to concretionary action, nor by that which assumes the direct deposition of ferric hydrate upon the interior of rock (limestone?) cavities. They may, how- ever, be explained by assuming that the bombs are the residual masses, remaining after oxidation, of iron sulphides or carbonates containing sand or clay or both in varying proportions. If the material from which this ore is formed consists of sand- stone, or of sandy slate, or of clay slate, impregnated more or less completely with pyrite or siderite, the formation of bombshells, con- taining just such materials as are found in these shells, may be readily explained, especially if the iron impregnation be in the form of pyrite or marcasite, that is, FeS,. 4 138 CHANCE—THE ORIGIN OF BOMBSHELL ORE. [May rs, If such sandstone or slate, is broken and fissured by faulting and crushing, and by the development of cleavage planes, oxidation by percolating waters will proceed along the joints or planes which form the channels through which these waters circulate, and in each fragment of the mineralized rock oxidation will commence upon the outside and progress towards the center. In this way on outer skin or shell of limonite first forms on the outside of the fragment, for if the iron be present as pyrite or mar- casite while some of it may be removed as ferrous sulphate, this salt, if formed, may immediately be oxidized and precipitated in situ as ferric hydrate. The sulphuric acid formed by the oxidation of the remaining molecule of sulphur will attack and decompose the clay of the gangue, removing the bases as sulphates in solution; the silicic acid also escaping in solution, or combining with iron oxides to form iron silicates, remains as an integral part of the ore. If clay be present in large quantity a portion will remain unde- composed in the center of the bomb, together with all of the sand originally present in the gangue. Hence, if the original pyritic material has a clayey (slate) gangue, bombs may form containing no residual matter, or containing more or less clay; if the gangue be sand and clay (arenaceous slate), the sand only, or sand and clay may remain; if the gangue be sand only, some of this will remain as an impurity in the limonite forming the body of the shell, and some as a partial filling of the interior of the bomb. It is now well known that pyrite (or marcasite) oxidizing under- ground, whether by waters carrying free oxygen, or by waters con- taining no uncombined oxygen, or by reactions involving hydrolysis, does not behave in the same way as when oxidized by exposure to the air above-ground. One of the most common reactions above-ground is that in which sulphur is set free, often written: FeS, + 40= FeSO, +S, but this rarely occurs beneath the surface, for the gossans of pyritic veins seldom carry free sulphur, although there are a few noted examples in which large deposits of sulphur are found between the surface and the unoxidized portions of such veins. 1908]. CHANCE—THE ORIGIN OF BOMBSHELL ORE. 139 In the absence of oxygen, carbonates in solution may, as shown by Dr. N. H. Stokes, completely oxidize the iron of pyrite or mar- casite thus: 8FeS, + 15Na,CO, = 4Fe,O; + 14Na,S + Na,S,O0, + 15CO,, and under proper conditions of temperature and pressure the ferric oxide thus formed may be deposited as hydrate; but these reactions do not satisfy the observed conditions and it seems more probable that oxidation near the surface has proceeded as indicated by some of the following reactions: FeS, + H,O + 70 = FeSO, + H,SO,; 3FeS, + 8H,O + 220=Fe,0,, 3H,O + FeSO, + 5H.SO,; 2FeSO, + 5H,O + O=Fe,O0,, 3H,O + 2H,SO,; ‘ 2FeS, + 7H,O + 150=—Fe,O;, 3H,O + 4H,SO,; 2FeS, + 4H,O + 150 = Fe,O, + 4H,SO,; 2FeSO, + 2H,O + O= Fe,O, + 2H,SQ,; 6FeSO, + 30 = Fe,O, + 2Fe,(SO,)s; 6FeSO, + 3H,O + 30= Fe,O,, 3H,O-+ 2Fe,(SO,),; 2Fe,(SO,), + 2FeS, + 4H,O + 120 = 6FeSO, + 4H,SO,. The sulphuric acid having been formed in direct contact with the gangue, it is reasonable to suppose that it must at once attack any clay or other decomposable material, and the removal of the soluble silicates and silicic acid by transfusion through the walls of the bomb is readily pictured. It is, however, possible that the colloidal silicic acid may be retained, and further that it may perhaps often be set free in a gelatinous condition. This latter hypothesis may account for the frequent presence in such ores of a skeleton of amorphous silica which appears to completely ramify some parts of the limonite. If the oxidation proceed according to these equations, the succes- sive additions of layers of limonite to the interior of the shells is doubtless due to the further oxidation of the ferrous sulphate .as above shown, the oxidation of the solution occurring at or in the wall of the shell where the solutions, in escaping by transfusion through the walls of the shell, are met by oxidizing waters transfusing towards the center of the shell. Under such conditions the ferric 140 CHANCE—THE ORIGIN OF BOMBSHELL ORE. [May 15, hydrate would be deposited in the pores of the shell or upon its inner surface. In attempting to picture these reactions and their results, it is important to remember the extremely slow rate at which oxidation proceeds under such conditions. Even at the surface where decom- position is comparatively rapid, the oxidation of pyrite appears to progress at a very slow rate, perhaps not exceeding an inch or a few inches in depth in several hundred years. If the iron be present as carbonate, a precisely similar series of reactions may be conceived, in which carbonic acid transposes the silicates, freeing silicic acid and removing the bases as soluble carbonates. Other observers have noted the occasional presence of a central core of siderite or pyrite in bombshell ore, but have generally attrib- uted the presence of such cores to concretionary action and replace- ment by sulphates. (accompanied by reduction to sulphide) or carbonates in solution. The foregoing theory, advanced to account for the origin of bombshell ore, is based upon a study of these deposits dating back to 1885—when the writer was personally engaged in mining brown- hematite ore—and upon examinations of many specintens which show more or less clearly the character of the original material from which such ore is formed. It will form an integral part of a broader statement, extending the application of this theory to the genesis of limonite ores, and including a discussion of the original sources of the iron, methods of mineralization, and subsequent decomposition and precipitation. PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE VoL. XLVII May-—Aucust, 1908. No. 189. THE SIGN AND NAME FOR PLANET IN BABYLONIAN. By MORRIS JASTROW, Jr. (Read April 25, 1908.) Kugler begins his valuable work on Babylonian astronomy? with a discussion of the ordinary name for planet in Babylonian, namely, bibbu, and for which the ideographic designation is Lu-Bat.2? He *“Sternkunde und Sterndienst in Babel” (Miinster, 1907), I., pp. 7-0. ? That this combination is used for planet in general follows from such passages as (1) Thompson, “Reports of the Magicians and Astrologers,” No. 112 Rev. 7; 236 B Rev. 4, where Lu-Bat occurs with the plural sign to designate the planets in general; See also nos. 88 Obv. 4 and Rev. 1; 89 Rev. 6; tor Oby. 5; 103 Obv. 6, Rev. 7; 163 Obv. 4; 167 Rev. 1; 172 Rev. 1 and 3; 175 Obv. 4; 200 Rev. 5; 216 Rev. 1; 218 Obv. 1; 218 A Obv. 5; 219 Obv. 1; 220 Obv. 1; 222 Obv. 1; 223 Obv. 1; 224 Obv. 3; 225 Obv. 4; 229 A Obv. 1, 2, 4; 232 Rev. 1; 234 Obv. 3; 234 A Rev. 1; 235 Obv. 11; 244 C Obv. 6, where Lu-Bat is used for planet in general. It is to be noted, however, that the only planets which are regularly designated by means of Lu-Bat are Mercury (Lu-Bat Gu-Up) and Saturn (Lu-Bat Sac-US). So in the famous list of planets ITR 48; 50-54 a-b and IIIR 57, No. 6, 65-67, and Thomp- son, /. c., passim, though occasionally even in the case of these two planets the element Lu-Bat is omitted, e. g., Thompson, /. c., Nos. 105 Obv. 8; 215 Obv. 1; 217 Obv. 1; 223 Obv. 4; 228 Obv. 1; (Gu-Up) and 167 Rev. 4 (Sac-US). Further references in Kugler, 1. c., p. 12. Occasionally also Mars is desig- nated as Lu-Bat Dir instead of (il) ZAat-Bat-(a-nu), so e. g., Thompson No. 146 Rev. 4-6, and 195 Rev. 1-2, where in both cases a gloss Lu-Bat Dir = (il) Zaut-BaT (-a-nu) furnishes the proof for the identification. In the: later period (after c. 400 B. C.) Saturn is designated as GI and Mars as AN. See Kugler /. c., p. 12, including the note on that page. PROC, AMER. PHIL. SOC. XLVII. 189 J, PRINTED SEPTEMBER Ig, 1908. 142 JASTROW—THE SIGN AND NAME [April 25, accepts the interpretation proposed as long ago as 1890 by Jensen® for the ideographic compound as “ frei weidendes, abseits weidendes Schaf.” This view rests on the identification of the first sign Lu as “sheep,” while the second is taken in the sense of “ to remove,’ the combination thus expressing the movement of the planets, like sheep that wander away from the flock. That Jensen was right in his explanation of the first element as “ sheep” follows from various considerations, among which the testimony of the lexicographical list ITR. 6, 4 c-d by itself, Lu-Bat = bi-ib-bu, is decisive, since in the same list Lu-Ici is explained as /u-li-mu (1. 8) “ram” or “ bell- wether ” and Lu is the common ideogram for immcru the ordinary term for “sheep.”> In addition we have the equation IIR. 39, No. 5, 62 a-b (il) bi-tb-bu = (il) Lu-Bat. Jensen’s explanation, however, of the second element is not satis- factory. In the first place the equation Bat = msi (“to remove ”) does not represent the most common value of the ideograph in ques- tion, for the various meanings of which it seems more reasonable to start from the fundamental notion of “coming to completion,’”® whence we have the further development in two directions: (1) “coming to an end” (gamaru, kati, Br. Nos. 1499, 1512, etc.), “closing up” (sakku, sikéru Meissner, Assyr. Ideogramme, Nos. 869-872); “removing” (nisi, Br. No. 1525); “growing old” (labaru, Br. No. 1515) ; “ die” (matu, etc., Br. Nos. 1517-19, 1527, 1533); “set at rest” (pasahu, Br. No. 1528): (2) “ Completion i in the sense of “ fullness” and “ vitality,’ consequently, “life” (balatu, Br. No. 1494) ; “being ” (basi, Br. No. 1495) ; “ blood” *Kosmologie der Babylonier, p. 99. Hommel (Aufsatze und Abhand- lungen p. 379) thinks that the designation bibbu which he takes as “ram” is an allusion to the “solar” character of the planets, but this is even less plau- sible than Jensen’s explanation. “Cf. Briinnow, No. 1525 (BatT= nisi). *See Muss-Arnolt, Assyr, Dict., p. 61b. Note also that in the list IIR. 6, 5-8 we have the: group bi-ib-bu, a-tu-du (“he-goat”), Sap-pa-ru (“ mountain-goat”) and lu-li-mu. * We must bear in mind as Thureau-Dangin, “Recherches sur I’ Origine de l’Ecriture cuneiforme,” No. 11, has pointed out, that two originally dis- tinct signs have been confounded in Bat, so that all meanings associated, e. g., with pitti (Br. No. 1529) must be referred to No. 278 (p. 45) and explained accordingly. 1908.] FOR PLANET IN BABYLONIAN. 143 (damu, Br. No. 1503), and “ rule” (bélu, etc., Br. No. 1496; Meiss- ner, No. 856), as manifestations of vitality and power as well as “strong” (ikdu, Meissner, No. 851), “ protect” (emt, Meissner, No. 853), etc. The idea of “ removing ” falls, therefore, in the cate- gory of a secondaryor tertiary derivative from the fundamental value of the sign Bat. In the second place, it is rather a violent transition from the sense of “ removing ”’ to that of “ pasturing by itself” and the like. Nor does the metaphor introduced in the Babylonian crea- tion epic’ (Tablet VII., 111, ed. King) where the stars, or rather the gods, are compared to sheep under the guidance of Marduk strengthen the conclusion that the planets are sheep that “ pasture aside’ from the stars in general, since the passage does not refer specifically to the planets. This passage, as well as the others ad- duced by Kugler (J. c., p. 7), merely justifies the interpretation of the first element in Lu-Bat as “ sheep.” For the second element we must start from the much more common meaning attaching to the sign in question, namely, “dead” (mitu). The Babylonians them- selves had this equation in mind when they explained Lu-Batas mus- mit bu-lim, “ causing cattle to die” (VR, 46, No. I, rev. 41) even though this explanation is to be regarded as a fanciful one.® Taking the two signs as they stand, the simplest explanation is to interpret them as “ dead sheep ” in the sense of a sacrificial animal. To the question which now arises, what connection is there between the planets and “ dead sheep,” the divination texts, I venture to think, furnish a satisfactory answer. II. On the basis of recent researches,® we must distinguish in Baby- See Kugler, 1. c., p. 7. ® Recognized as fanciful by Jensen, Kosmologie, p. 96. Kugler’s attempt (1. ¢.) to reconcile this explanation with the interpretation offered in astro- logical texts whereby certain phenomena connected with the planets prognos- ticate death is. very artificial and encounters a fatal objection from the con- sideration that the prognostication of death in one form or other, is a com- mon interpretation of omens, indeed one of the commonest. See examples in Jastrow, “ Religion Babyloniens und Assyriens,” II,. pp. 261, 298, 328, 329, 331, 333, 343, etc. * See Jastrow, /. c., pp. 212 f., and various papers by the writer as, e. g., “Signs and Names of the Liver in Babylonian” (Zeitschrift fiir Assyr. XX., p. 111 f.), “ The Liver in Divination and the Beginnings of Anatomy” (Uni- versity of Pennsylvania Medical Bulletin, January, 1908). 144 JASTROW—THE SIGN AND NAME [April 25, lonian-Assyrian methods of divining the future two classes: (1) what we may call voluntary divination, and (2) involuntary divina- tion. The characteristic feature of voluntary divination lies in delib- erately seeking out some object by means of which an answer to a specific question regarding the future or the outcome of an under- taking, a sickness or what-not is furnished. The signs furnished by the liver of an animal selected as a sacrifice belong to this category; likewise the observation of the flight of birds sent out for the pur- pose of securing omens, the throwing of arrows before the image of a deity and the like. Involuntary divination, on the other hand, is concerned with the attempt to interpret signs that force themselves on our notice, such as phenomena connected with the sun, moon, planets and stars, the movements of clouds, earthquakes and storms; the actions of animals—dogs, snakes, locusts, birds, etc., that one happens to encounter and all the unusual or significant happenings and accidents in human life, while dreams form a special subdivision in this class of involuntary divination. We might for the sake of convenience distinguish the signs furnished by voluntary divination as “omens” and those of involuntary divination as “ portents,”’ but however we may distinguish them, the recognition of these two dis- tinct classes is fundamental to an understanding of the general sub- ject of divination. Confining ourselves to Babylonia and Assyria, the chief method of voluntary divination was the inspection of the liver of the sac- rificial animal and the chief method of involuntary divination, the observation of phenomena of the heavens. The correctness of this thesis is shown by the wide scope of these methods as revealed in the texts themselves.‘° Both methods rest on a well-defined theory, the inspection of the liver on the basis of the primitive view that the liver was the seat of vitality, of the intellect, of both the higher and lower emotions—in short, the seat of the soul, as that term was popularly understood.*4 The deity in accepting the sacri- ficial animal identifies himself, as it were, with the animal, becomes * See Jastrow, /. c., II., p. 209 f£—especially note 1 on p. 210. See parts 11-12 of this work for “liver” omens and the forthcoming parts 13 and 14 for “ astrological ” omens. 4 Jastrow, /. c., pp. 213 f. 1908. ] FOR PLANET IN BABYLONIAN. 145 one with it and, accordingly, the liver of the animal reflects the mind and will of the god. If one can therefore read the liver correctly, one enters, as it were, into the workshop of the deity. The mind of the . animal and the mind of the deity become for this specific occasion like two watches regulated to be in perfect accord. The divining of the future through the observation of the phe- nomena in the heavens rests on the identification (or personification) of the gods with the sun, moon, planets and stars. The movements of these bodies, the changes in their aspects and the variations in their relationship to one another represent, as it were, the activity of the gods and since, according to the current theory, all happen- ings on earth are due to the gods or to one god or the other, a knowl- edge of what the activity in the heavens portends furnishes the means of foretelling what is to happen on earth. In time no doubt the theory was perfected, at least in the theological circles of Baby- lonia and Assyria, into a complete correspondence between occur- rences on earth and the decision to bring about these occurrences by the manifested activity of the gods in the heavens ; but even without the perfected theory, the repeated observation of the kind of happen- ings on earth coincident with conditions and phenomena in the heavens would have led to attaching importance to these conditions— both those of a usual order and those of a more or less unusual nature. Of these two chief divisions of divination, it is evident that the inspection of the liver, connected as it is with a primitive view of that organ, can be accounted for as the distinct outgrowth of popular beliefs, whereas the divination through the phenomena of the heavens not only makes greater demands on scientific or pseudo- scientific knowledge but presupposes also a conception of world- philosophy which can hardly be termed popular. The personifica- tion of the sun and moon is, of course, an element in all primitive phases of belief, but the, extension of such personification to the planets and stars belongs to a higher order of thought, since the bearings of those bodies on the life, happiness and fate of mankind are of a more remote and a more indirect character than in the case of the two luminaries ; and when we come to the projection of prac- tically all the activity of the gods on to the heavens, we have defi- nitely passed beyond the intellectual range of popular fancy and 146 JASTROW—THE SIGN AND NAME [April 25, have entered the domain of distinctly theological speculation. If the views of the school associated with the names of Winckler and . Jeremias, that the entire Babylonian religion is under the sway of “astral” conceptions, turn out to be correct, it will also have to be recognized that the underlying “ Weltanschauung ” is a product of the schools rather than an expression of popular notions.4* I venture to think that one of the weaknesses of the “astral” theory, which has from other points of view so much in its favor, is this failure on the part of its promoters to recognize the essentially “learned ” character of what according to them became the prevailing world- philosophy in the ancient Orient and which must for a long time at least have separated it sharply from the much lower plane of popular beliefs and fancies. . Be this as it may, the development of a method of divina- tion, through elaborate observations of the movements and positions of sun, moon, planets and stars, it will be admitted, belongs to a later stage in the unfolding of religious rites than so primitive a method as the inspection of the liver of a sacrificial animal. The persistence of astrology among advanced cultures as in India and Persia and in western Europe’? down to the threshold of modern times, whereas “ liver” divination disappeared with advancing cul- ture everywhere except among the Babylonians and Assyrians and the Greeks, Romans and Etruscans,!* clinches the argument in favor of divination through the liver as the earlier and more primitive method. If this be admitted, it would be reasonable to find in the ‘ "See also Comont, “Les Religions Orientales dans le Paganisme Romain” (Paris, 1907), p. 197. *See the summary by Jeremias, “Das Alte Testament im Lichte des Orients” (1 ed.), p. 7, note 1. ** Roman divination is dependent upon Etruscan, while in the case of Greek divination it is still a question whether we are to assume direct in- fluence from Babylonia or likewise through the mediation of the Etruscans. In either case we have only two systems of “liver” divination surviving among cultured nations—the Babylonian and the Etruscan; and further- investigations may definitely confirm the view which on the surface seems plausible that “liver” divination among the Etruscans stands in some direct connection with Babylonian divination. If this be so, then the single cause to which the persistence of “liver” divination in certain quarters is to be ascribed is the elaboration of the complicated and ingenious system of inter- pretation which we owe to Babylonian priests. See Jastrow, II., pp. 215 and 320, note 3. 1908.] FOR PLANET IN BABYLONIAN. 147 later method of divination through the heavens, traces of the earlier one, if not indeed some link directly connecting the two. Among the Etruscans we actually encounter such a link in the interesting circumstance that the famous “bronze liver” of Piacenza, pre- pared like the Babylonian clay model of a liver’** as an object lesson for instruction in the temple schools, is divided off along the margin into sixteen regions, corresponding with the ordinary divisions of the heavens and that the forty Etruscan words with which the surface of the liver is covered are names of deities. Whether we accept Thulin’s view,’* who sees a direct relationship between the enumera- tion of the gods and the list and arrangement given by Martianus Capella, or follow Korte,’® in either case the “liver” reproduces the recognized divisions of the heavens and through this combina- tion the liver becomes, as it were, a microcosm reflecting the macrocosm. The much-discussed problem'®* whether this re- markable object dating from about the third century B. C. is a “liver” or, as was first supposed, a “ templum,” thus resolves itself into the thesis that it is both. To use the words of Kérte in his paper in summarizing the results of twenty-five years of study of this object :*° “The liver as the seat of life according to the view of antiquity appears as a minature reproduction of the universe. As the latter, so the liver is divided into a right and left half,” a day division and a night division, the line of division corresponding to the line dividing the universe into east and west. As the vault of heaven, so the edge of the liver is divided into 16 regions in which the gods who furnish portents dwell.” *%See Korte, “Die Bronzeleber von Piacenza” (Mitteil. d Kaiserl. Deutsch. Archeolog.-Instituts., XX., pp. 348-379), the latest and probably final word on the subject. *@ Cuneiform Texts, VI., Pl. 1-2 and photograph. 4“ Die Gotter des Martianus Capella und der Bronzeleber von Piacenza” (Giessen, 1906), pp. 31-59. * Korte, /. c., p. 367 f. a See the references in Korte, p. 349 f., to which Nicola Terzaghi, “La piu recente Interpretazione dei Mundus-Templum di Piacenza” (Bolletino Storico Piacentino, 1906, Maggio-Giugno) is to be added. * Korte, |. ¢., p. 362. “Referring to the band on the reverse of the object. See the illustra- tion in K6rte’s article, p. 356. 148 JASTROW—THE SIGN AND NAME | April 2s, III. If, therefore, among the Etruscans we find the unmistakable proof of a direct link between the two classes of divination, we should be prepared to find a similar association in Babylonia and Assyria. I believe that the ordinary name and sign for planet in Babylonia points in this direction. While already in early days we find various animals and all kinds of products dedicated as offer- ings to the gods,’* for purposes of divination the only animal set aside was the sheep. This follows not only ‘from the fact that the fa- mous clay model of a liver found near Bagdad is that of a sheep,’® but from the specific references to sheep in “liver” divination texts and to no other animal.?° The sheep thus becomes the animal of divina- tion par excellence, and we can well suppose that the word itself should come to be used as synonymous with divination. Such a usage would be paralleled by the extension of the term auspicium in Latin, which from being an omen derived through “ bird observation ” was applied to any kind of an omen or portent, so that an inspection * See Thureau-Dangin, “Die Sumerischen und Akkadischen K6nigsin- schriften” (Leipzig, 1907), pp. 16, 80, 84, 86, 88, 124, etc. I cannot here enter into a full discussion of the nature of sacrifices among the Baby- lonians and Assyrians but it may be proper to point out that in an elaborate ritual controlled by an extended priestly organization we must sharply dif- ferentiate between (1) offerings that constitute part of the income of the temples, (2) voluntary gifts, (3) sacrifices offered in connection with purifica- tion or expiatory rites and (4) sacrifices offered directly to and for the god. So far as I can see sacrifices of the latter kind were brought only when an answer to a specific question was desired, so that it would appear that divina- tion forms the starting point for the development of the whole idea of sacri- fice in the proper sense in Babylonia. “CT, VI, Pl. 1. See Jastrow, 1. c., IL., p. 218 note 1, where a reference should have been given to Stieda, “ Ueber die aeltesten bildlichen Darstel- lungen der Leber” (Bonnet-Merkel, Anatomische Hefte XV., p. 697), who shows that it is (as also in the case of the bronze liver of Piacenza) the liver of a sheep and not of a goat—as had been supposed by some scholars. *E. g., CT, XX., 1, 1—in the opening line of the first tablet of a series dealing with “liver” divination; also Boissier, “ Documents Assyriens relatifs aux Présages,” p. 97, I1; 212, 27; also in the “omen” text CT., IV., Pl. 34, 9; in the omen report of the Cassite period (Clay, Cassite Archives, XIV., Pl. 4, Obv. 10, and lastly the constant mention of the “sheep” in the omens attached to Knudtzon, Assyr. Gebete an den Sonnengott. Note also the expression bél immeri “ owner of the sheep” (CT, XX., 33, 93 and Boissier, Documents, p. 96, 13). The addition of NITA to Lu shows that a “male” sheep was selected for the purpose. 1908.] FOR PLANET IN BABYLONIAN. 149 of the liver of an animal for the purpose of securing an “omen” was also designated as an auspicium.** Similiarly, in Greek the word dps, “ bird,” is used for any kind of an omen and my colleague, ‘ Professor Lamberton, has kindly called my attention to the inter- esting passage in the Birds of Aristophanes in which this usage finds a striking illustration. In the “ Parabasis,” after indicating all the blessings that accrue to men from the birds, the chorus turns to divination and continues as follows :?? “You consider all things a bird, whatever gives a decision through divination. With you a word is a ‘bird,’ and you call a sneeze a ‘ bird,’ a sound a ‘bird,’ a sudden meeting a ‘bird,’ and an ass a ‘bird.’ Are we not clearly a prophetic Apollo to you?” The sheep, being the animal of divination par excellence in Babylonia, would in the same way become the Babylonian term for an “auspicium” in general. If we assume that this use of the term lurks in the application of “sheep” as the designation of a planet, a satisfactory explanation can be found for the addition of the sign Bat to the sign for “sheep” which has more specifically the same force in the combination Lu-Bart as in the combination IIR: 27, No. 2, Obv. 46, c—d, Ur-Bar, i. e., “ dead liver ” in the sense of the liver of a sacrificial lamb and hence as the equivalent of ter-tu Sa ha-Se-e, “ omen through the liver.”?* The combination Lu-Bat thus expresses more precisely than Lu alone the association of an “omen” with a “sheep,” and we would be justified in rendering the combination as “sheep omen,” and then through the association of ideas above pointed out, as a general term for “ omen.’’*4 See Pauly-Wissowa, “ Real-Encyclopaedie,” (new ed.), IL., p. 2580 f. 211. 719-22 (ed. Van Leeuwen, Leiden, 1893). Dr. R. G. Kent, of the University of Penna., also calls my attention to the interesting passage in Xenophon’s Anabasis (111, 2,9) where a “ sneeze” as a good sign is spoken of as dwvd¢e or “bird” in the general sense of an omen. 72On the word hasit for liver which may have been used in earlier days in place of kabittu see Jastrow, /. c., IL, p. 213, note 1, and p. 276, note 7. *Tt is to be noted that at least in one passage in a “liver divination” the sign Bat is added to Lu-Nrra “ male sheep,” namely Boissier, Doc. Assyr., p. 212, 27, ultu libbi Lu-Nira Bat (u) tértu (written Ur-Bat as in the pas- sage IIR 27) tu-Se-la-a, i. e., “ Out of a dead sheep thou shalt bring forth an omen,” where the phonetic complement u added to Bat suggests the reading mitu and where “dead sheep” is clearly the equivalent of “ sacrificial sheep ” or “omen sheep.” 150 JASTROW—THE SIGN AND NAME [April a5) Now what was the purpose for which the movements of the planets were observed by the Babylonians? What other than to secure through such observation, signs by means of which the future could be divined? The planets were, primarily, regarded as “omens ” and since, as has been above set forth, divination through the heavens follows in point of time divination through the liver of the sheep, we would expect conceptions and terms used in “ liver ” divination to be transferred to astrological divination. The use of the term “sheep” as the designation of the planets observed to secure omens, precisely as omens were furnished by means of sacri- ficial sheep, I, accordingly, take as an illustration of this dependence of astrology upon hepatoscopy, forming, as it were, the connecting link between the two. It may be noted in. this connection that the interpretations given in astrological texts to signs observed are paral- leled in the “liver” divination texts,?> and there can be little doubt that they are transferred bodily from the latter and earlier class of texts to the former. The explanation here proposed, according to which Lu-Bat as applied to the planets conveys the notion that they were regarded as “omens” or means of securing omens, throws a new light upon the statement in Diodorus*® that the Babylonians commonly called the five planets éppyveis, i. e., “ interpreters,” adding as a reason for the designation that the planets were regarded as “ inter- preting’”’ for mankind the intention of the gods. Bouché-Leclereq (“ L’Astrologie Grecque,” p. 40, note 3), recognizes that the term “interpreters” does not embody a Greek tradition, but the notice in Diodorus, so far from being, as he supposes, of “ doubtful value,” reflects the perfectly correct view that the planets were used as “omens ”27 and the term “ interpreters ” is evidently an attempt to ce * The interpretations in the “astrological” texts are in fact practically identical with those in “liver” divination, furnishing the same references to public events and differing merely in containing more references to crops, to prices of food and to famine. Cf., e. g., Craig, “ Astrolog.-Astronom. texts,” Pl. 2, 3; 20, 22 with CT, XX., 26, Obv. 3; Boissier, Doc. Assyr., 7, 21; Craig 20, 31 with CT, XX., 32, 54; 99; 100 (where ilu = Nergal). Cf. Jastrow, I. c., IL, p. 342, note 11). Bibl. Histor., Book II. (ed. Dindorf), 30, 4. * To be sure, what Diodorus says in addition why the planets and not also the other stars were regarded as “interpreters” is rather beside the 1908.] FOR PLANET IN BABYLONIAN, 151 convey this idea. The term may, therefore, be regarded as a render- ing of the Babylonian designation “sheep omen” in the general sense above pointed out. The objection may be raised at this point, why should not the moon and sun, as playing an equally if not more important rdle in divination lore, likewise have been designated as Lu-Bat in the generic sense of an “omen” or “auspicium”? The answer is obvious. Sun and moon cults are such ingredient parts of early forms of religion everywhere and the dependence of human for- tune, life, health and welfare upon these two luminaries is so direct that other factors were at work in the development of conceptions regarding these two deities than merely the observation of their movements and changing relationship to one another as a basis for determining what these deities were preparing for mankind. Their cult precedes their introduction into divination texts, whereas the planets were observed solely for purposes of divination. Since the influence of the latter on human life was a matter of speculation rather than of direct experience, the basic and primary motive for noting their movements was in connection with the view that, as rep- resenting gods, their movements indicated the activity of these gods in preparing the events that were to happen on earth. The old and long established names and designations for sun and moon were accordingly retained, whereas the new term chosen for the planets was ordinarily restricted to them. Occasionally, however, so, e. g., III. R, 57, No. 6, 65-67, sun, moon and the five planets are sum- marized as seven Lu-Bat (pl.). That the association of ideas did not, on the other hand, lead to the extension of Lu-Bar to the stars in general constitutes no valid objection to the thesis here propounded. In the divination texts the number of stars introduced, outside of the planets, is not large and their role is quite secondary,?* and it is not until we reach the period when astronomy becomes more definitely differentiated as a science from astrology, when calculations are made and “ planet ” tables are mark; and shows that he no longer fully understood the force of the Baby- lonian designation which he here faithfully reproduces. In astrological texts proper as distinguished from astronomical tablets, the stars mentioned are chiefly certain ones belonging to the constellations of the ecliptic and which are frequently introduced as guides and indications for fixing the position of the planets, rather than as omens. © 152 JASTROW—THE SIGN AND NAME [April 25, prepared independently of divination, that star-lore assumes larger dimensions. Besides, in securing omens the positions of the stars constitute a minor factor and are of value chiefly, if not exclusively, in relationship to phenomena connected with the planets—a condition which is specially applicable to the relationship between the planets and the constellations of the zodiac. Attention has already been called to the fact that although Lu- Bat is commonly applied to any planet, there are only two planets— Mercury and Saturn—that regularly appear written with this com- pound ideograph,”® the former being designated as Lu-Bat Gu- Up,*® the latter as Lu-Bat Sac-Us, while Mars occasionally appears as Lu-Bat Drr.*t The other planets appear in the lists IIR, 48, 48-54 ab and IIIR, 57, No. 6, 65-67, as (il) Sut-pa-Up-Du-a (Jupiter) (il) Dm-Bar (Venus) and Zat-Bat-a-nu (Mars), with Mvu_t=kakkabu interchanging with an=ilu. Moreover, the phonetic reading bi-ib-bu in the latter list for Lu-Bat Gu-up points to Mercury as being the planet par excellence. Why should Mer- cury have been assigned to this preéminent position among the planets? It has been suggested to me* that the position of Mer- cury nearest to the sun may have led to its being looked upon as the chief planet for purposes of divination and it is perhaps not without significance that in Greek astrology Mercury, frequently designated as ortABwr, “ shining,’** is closely associated with the sun, and indeed at times identified with Apollo.** Certainly, the peculiar conceptions connected with Mercury in the astrology of the Greeks and of other nations—whose dependence upon Baby- loriian beliefs and speculations is generally admitted—sharply sepa- rate that planet from his fellows. While the others, e. g., are con- ceived as masculine or feminine, Mercury, and Mercury alone, is double sexed.**’ Qualities are heaped upon Mercury in profusion, ® See above, p. 141, note 2. * Generally read Gup-Up but the reading Gu-Up seems preferable. *t See above, p. 141, note 2. “By my friend, Mr. H. H. Furness, Jr., whose suggestion commended itself to my colleague, Professor C. L. Doolittle, Director of the Flower Observatory (University of Pennsylvania). * Bouché-Leclercq, “ L’Astrologie Grecque,” pp. 66 and 100. * Tbid., p. 100, note 5. * Ibid., p. 102. So also in modern astrology. See Ellen H. Bennett, “ Astrology” (New York, 1897), p. 98. 1908. ] FOR PLANET IN BABYLONIAN. 153 in contradistinction to the other planets to whom generally a single dominant trait is given. Intelligence, thought, feeling, eloquence, artistic spirit are all associated with Mercury,*® which thus be- comes, as it were, the “soul” among the planets and it will not seem far-fetched to see in the fancy which makes Mercury the planet of revelation and of language*’ a trace of primitive views regarding the seat of vitality. In accord with this, we actually find Mercury assigned to the liver** as the organ of revelation, though in deference to later views of the liver as the seat of the affections specifically—and not of all intellectual life and of ail emotions—Venus is sometimes identified with this organ.*® To be sure, stich associations of ideas have not as yet been encountered in Babylonian texts and therefore a certain reserve is called for. On the other hand, the dependence of Greek astrology on Babylonian conceptions, fancies and prototypes is so evident at every turn*® that we are justified in assuming a large measure of identity between the two systems of divination, just as, on the other hand, modern astrology is full of conceits and notions that can be paralleled in ancient Greece, India and Persia. Another factor that may have led to assigning to Mercury a specially prominent place among the_planets for purposes of divi- nation is the circumstance that by virtue of its close position to the sun and its small size, it makes its circuit in the short space of twelve weeks and four days, or 87.97 solar days. Hence, since the basis of divination in the case of the planets is largely bound up with their relative position to the sun—upper conjunction, ascent, culmination, standstill, descent, lower conjunction*t—Mercury would present a far larger proportion of changes in any given time than any other planet. In the case of frequent observations, Mercury would thus play a more prominent part than the other planets whose movements except for periods of some duration would furnish less of moment *® Bouché-Leclercq, p. 101; Bennett, p. 99. * Bouché-Leclercq, pp. 312, 321, 323. * Tbid., p. 312 and 323. ™ Ibid, p. 321- * See Bouché-Leclercq’s summary, pp. 70-71. “ See the valuable discussion in Kugler, 3. ¢., p. 20 f., of the Babylonian equivalents for those terms. 154 JASTROW—THE SIGN AND NAME [April a5, to the observer, dependent upon the naked eye. But whatever the reasons, we can only conclude from the fact that Mercury is the “sheep ” par excellence that it was at one time singled out as the planet of revelation and that, therefore, it was in all probability the first planet whose movements were observed for the purpose of securing through them a means of determining what events the gods were preparing to take place on earth. The designation of Saturn as lulimu, “ ram,’ I am inclined to regard of secondary origin, that is to say, dependent upon the appli- cation of bi-ib-bu to Mercury—the latter term taken no longer in the sense of an “omen ”’ but already as a specific and distinguishing designation. As companion piece, therefore, to Mercury as a “ sheep,’ Saturn was called a “ram” just as the designation of the seven Masi-stars by the determinative Lu (‘“sheep”)* is a secondary extension from Lu-Bat, limited originally to the planets. Saturn presents in almost every respect a contrast to Mercury. It is infinitely larger** in bulk, at a great distance from the sun, the most regular of the planets and the slowest in its motion, taking 10,759 days or 29.46 years to pass around the sun. In Greek astrology a preéminent position is accorded to Saturn,** which is expressed, for example, by making the planet the head and “brain” of the plan- etary world—reflecting the later view which placed the seat of the soul in the head,*® while the association of Saturn with Mercury “Kugler, |. ¢., p. 7. * Jupiter alone is larger. “ Bouché-Leclercq, J. c., p. 94 f. It is to be noted that Saturn is in Babylonian astrology called “the star of the sun” (as Diodorus, II., 30, also says)—which reminds one that Mercury (see above, p. 152) was identified with the sun in Greek astrology; the same appears to have been the case with Saturn. See Kugler, l. c., p. 8. “ Tbid., p. 95. The soul was placed successively (a) in the liver, (b) in the heart and (c) in the brain. “Liver” divination is the outward expression corresponding to the first stage. The addition of the “heart” (and then of other organs) to the “liver” in the examination of the sacrificial animal— as among the Romans—is a concession to the second stage, while phrenology is an expression—outside of the official cult—of the third stage. See Jastrow, “ Divination through the Liver and the Beginnings of Anatomy” (University of Pennsylvania Medical Bulletin, January, 1907). In a special paper on “ The Liver as the Seat of the Soul” I propose to treat in detail of these suc- cessive views. 1908.] FOR PLANET IN BABYLONIAN. 155 crops out in the belief which makes the history of the world begin with the reign of Saturn and end with that of Mercury.**® The prominence of Saturn in Babylonian-Assyrian astrological texts is in accord with this association with Mercury as a second Lu-Bat par excellence.*® In modern astrology Saturn continues to play a particularly con- spicuous role**—all of which points to its having been the first planet to become, by the law of contrasts, associated with the original “source” of divination among the planets—Mercury. Lastly, a word regarding the ideographic designations of these two “sheep”—Mercury and Saturn. Kugler,** following in part Jensen,*® proposes to take the element Gu-Up in Lu-Bat Gu-Up as karradu Sa urri,*° “ warrior of the light,” because shortly after his appearance in the East day triumphs over night. The explana- tion seems forced and it is hardly likely that a circumstance like this should have suggested a name for a planet. In view of the fact that Mercury and Saturn are the two planets more particularly des- ignated as Lu-Bat, it is more reasonable to see in Lu-Bat Gu-Up and Lu-Bat Sac-Us descriptions of characteristic features. For Sac-Us, fortunately, the equivalent, ka-a-ma-nu,*' has been defi- nitely ascertained and the meaning “regular” is also beyond doubt. The name was clearly given to the planet because of the slow and regular motion which is its distinguishing feature. Mercury, on the “ Bouché-Leclercq, pp. 187, 408 f. “* The statement of Diodorus (/. c.) that Saturn was regarded by the Babylonians as the most important for purposes of divination may correctly reflect a later stage when Saturn assumed the preéminent place once occupied by Mercury. * Bennet, I. c., p. 93. “Kugler, /. c., p. 10. On p. 218 he prefers the rendering “ full of light” (as Hommel, Aufsatze, p. 381, does) but the two ideas (“ full” in the sense of “strong” and “ warrior”) are correlated. ” “ Kosmologie,” p. 131, who takes Gup-UP as a single term = karradu “warrior” (Br. 5742). It is always to be born in mind that we are to substi- tute Mercury for Mars throughout Jensen’s volume—now that it has been definitely ascertained that Gup-Up= Mercury. and not Mars and Zat-Bat (a-nu) = muStabarru mutanu—= Mars not Mercury. *’Gup=karradu and Up=urru (Br. 7798)—though timu—“ day would suggest itself as more probable. ™ See Jensen, /. c., p. 114. Cf. 3 in Amos 5, 26. 156 JASTROW—THE SIGN AND NAME [April 25, other hand, is marked by its rapid and irregular course and I accord- ingly propose the equation Gu-Up = Sahatu—a common value of. the compound ideogram in “liver” divination texts in the sense of “hinder, check, restrain.’’®? Assuming the adjective formation Sahtu from this stem, the “ checked ” one as the designation of this planet would form a com- panion piece to kaimanu, the “regular” one. In contrast to kai- manu “ regular,” the designation Sahtu would, naturally, convey the notion of a body checked and restrained and therefore “ irregular ” in its motion.®® = Cf. Jastrow, II., p. 366, note 9. The gloss in Hesychius according to which SeAéBaro¢ is in Babylonian the “fire” star cannot be explained as Jensen “ Kosmologie,” p. 97, proposes, since he starts from the false assumption—since abandoned by him—that bibbu—the Lu-Bat par excellence is Mars, whereas it is Mercury. That Ber£éBarog designates Mars is however no doubt correct and since the com- mon ideographic designation for Mars is ZaLt-Bat—the addition of a-nu being a phonetic complement to suggest the phonetic reading muStabarru mutanu, “the one satiated with death ”—the correction of BeAéBarog to FeAéBaroc suggests itself as a simple solution of the problem. \ FURTHER RESEARCHES ON THE PHYSICS OF THE EARTH, AND ESPECIALLY ON THE FOLDING OF MOUNTAIN RANGES AND THE UPLIFT OF PLATEAUS AND CONTINENTS PRODUCED BY MOVEMENTS OF LAVA BENEATH THE CRUST ARISING FROM THE SECULAR LEAKAGE OF THE OCEAN BOTTOMS. By T. J. J. SEE, A.M., Lt.M., Sc.M. (Missov.), A.M., Po.D. (BErot.), Proressor oF MatHemartics, U. S. Navy, IN CHARGE OF THE NAVAL OBSERVATORY, Mare ISLAND, CALIFORNIA. (Read April 24, 1908.) I. GENERAL CONSIDERATIONS ON THE PHYSICS OF THE EARTH, WITH EspECIAL REFERENCE TO THE SECULAR LEAKAGE OF THE OcEANS AND THE RESULTING DEVELOPMENT OF MouNTAINS, PLATEAUS AND ISLANDS. § 1. Introductory Remarks.—In three papers recently communi- cated to the American Philosophical Society held at Philadelphia and since published in the proceedings of that Society,’ the writer has treated at some length of the cause of earthquakes, moun- 17. “The Cause of Earthquakes, Mountain Formation and kindred phen- omena connected with the Physics of the Earth,” Proc.. Am. Puutros. Soc., 1906. 2. “On the Temperature, Secular Cooling and Contraction of the Earth, and on the Theory of Earthquakes held by the Ancients,” Proc. Am. Puitos. Soc., 1907. 3. “The New Theory of Earthquakes and Mountain Formation as illus- trated by Processes now at work in the Depths of the Sea,” Proc. Am. Puitos. Soc., 1907; issued in March, 1908. The following shorter articles have also appeared: 4. “Outline of the New Theory of Earthquakes,’ Popular Astronomy, April, 1908. 5. “How the Mountains were Made in the Depths of the Sea,” Pacific Monthly, Sept., 1908. PROC, AMER. PHIL. SOC, XLVII. 189 K, PRINTED SEPTEMBER 21, 1908. 158 SEE—FURTHER RESEARCHES ON CApeil a4, tain formation and kindred phenomena connected with the physics of the earth. In the course of these three memoirs many important questions are considered, and it seems to ‘be rendered highly probable that six great classes of phenomena, not heretofore closely associated, depend on a single physical cause, namely, the secular leakage of the ocean bottoms, and the resulting movement of molten rock beneath the earth’s crust. The six classes of phenomena traced to a single physical cause are: (1) world-shaking earth- quakes; (2) the activity of volcanoes; (3) mountain formation; (4) the formation of islands and plateaus; (5) seismic sea waves; (6) the feeble attraction of mountains and plateaus long noticed in geodesy. The first of the memoirs printed by the American Philosophical Society deals with the problem of earthquakes in its general aspects, and sets forth grounds for the theory that these six classes of phe- nomena are directly connected and dependent on a single physical cause; the second examines the question of the earth’s temperature, secular cooling and contraction, and endeavors to show that the traditional theory of the changes noticed on the earth’s surface is not well founded; while the third seeks to demonstrate the more important conclusions reached in the first memoir, by an appeal to processes now at work in the depths of the sea, the meaning of which apparently is so plain as to admit of no possible doubt. The change in the point of view necessitated by the considera- tions brought forth in these papers is so remarkable as to be worthy of the attention of all who are interested in the grand science of natural philosophy. And we therefore propose to consider in this paper the physical basis of the theory of ocean leakage, the folding of mountain ranges and the uplift of plateaus and continents pro- duced by movements of lava beneath the crust, together with the historical aspects of the problems of the physics of the earth. Heretofore the nature of the forces which have folded mountain ranges and their relationship to those slow movements which have raised whole continents have been equally mysterious and bewilder- ing to the investigator. Accordingly any light which may be shed on this difficult subject will no doubt be exceedingly welcome to those who are interested in the progress of the physical sciences. 1908 ] THE PHYSICS OF THE EARTH. 159 As the leakage of the oceans seems to be clearly proved by the movements noticed in earthquakes, especially where mountain for- mation is now going on in the depths of the sea, and the seismic disturbances are therefore accompanied by the sinking of the sea bottom, as shown by the seismic sea waves which follow the earth- quakes, it seems legitimate to appeal to these movements of molten matter beneath the earth’s crust as the only available means of demonstrating the porosity and other physical properties of layers of granite twenty miles thick. Owing to the restricted conditions of human life, no experiments on such a grand scale can ever be at- tempted in our laboratories, however great the facilities at our command ; and our only means of ascertaining the truth with regard to the theory of ocean leakage is by careful observation in the great laboratory of nature. The leakage of the oceans involves three important questions: (1) The porosity of thick layers of matter such as those composing the earth’s crust; (2) the penetrability of the crust under steady fluid pressure, by which the capillary forces are made to aid the molecular forces producing penetration of the fluid; and (3) the accumulation of stresses depending on the forma- tion of steam in the layers just beneath the earth’s crust. The conditions existing in nature can scarcely be approximated in our laboratories, on account of the limitations of the forces at our command, but so far as experiments throw light on these great questions, the evidence tends to confirm the theory of ocean leakage. The well-known experiments of Daubrée, showing that under the action of capillary forces hot water will penetrate a layer of sand- stone against a strong counter pressure of steam, and by entering a cavity actually increase the steam pressure on the further side, has been justly held to afford evidence of the leakage of the earth’s crust, and of the probable mode of volcanic activity. If such action is possible in a minute way, it may easily operate on a vastly greater scale to produce the shaking of the crust in earthquakes, together with the uplift of mountains and the occasional outbreak of volcanoes. Now if the rock of the earth’s crust is at all as porous as we generally think, the constant pressure of the vertical column of 160 SEE—FURTHER RESEARCHES ON [April 24, water, often miles deep, resting on the ocean bed must tend to force the fluid deeper and deeper into the bowels of the earth. A study of what takes place on our earth under the observed con- ditions constitutes therefore one of the grandest problems in nat- ural philosophy. Indeed it may be said that the great laboratory of nature has magnificent experiments constantly going on. All that we need to do is to interpret these experiments correctly. The best way to do this is to select phenomena in which the processes are so clear as to be free from doubt; after we have found the law of the phenomena in cases which are beyond question, we may then generalize and interpret other phenomena, in which the relations are not so obvious. By gathering principles and laws from cases which are entirely clear, and working by degrees to understand those which are more obscure, we may finally arrive at the true processes even when the operations of nature are quite hidden from our view. Laws thus established by observation in the great laboratory of nature will obviously hold true of like experiments in the minute physical laboratories designed by man; and by noting the phenomena of the globe we may extend our knowledge of the universal proper- ties of matter under various physical conditions often more extreme than those ordinarily witnessed at the surface of the earth. § 2. Heretofore the ocean bottoms have been assumed to be water- tight.—The earth’s crust is made up chiefly of sedimentary, igneous and granitic rocks, and soil produced by the decomposition of the various kinds of rock under the action of water and the atmosphere. Nearly all of the sedimentary rocks are quite leaky, and moreover they absorb a great deal of moisture from the air; the formation of artesian wells and of natural springs depends primarily upon the percolation of water through rocks and layers of soil of various kinds. The leaky character of the sedimentary rocks is well known and has been generally recognized. But these rocks exist only near the surface, and do not extend more than a very few miles deep; consequently they could admit the water to but a slight depth into the earth’s interior. Below the sedimentary rocks lies the mass of granite which makes up by far the greater part of the earth’s crust. The granitic rocks, such as granite, andesite, dia- 1908. ] THE PHYSICS OF THE EARTH. 161 base, etc., are by no means so penetrable as the sedimentary rocks, and hence water has more difficulty in passing through them. And as the layers of this material composing the earth’s crust are about fifteen miles deep, it has been generally held that water would have difficulty in making its way down into the heated layers just beneath the crust. Indeed it has been practically as- sumed that the ocean bottoms are water-tight, in spite of the great fluid pressure constantly exerted by the mere depths of the water over a large part of the bottom of the sea. This fluid pressure in many places is great enough to throw a column of water to the free surface, over five miles high; and it operates not only from day to day, year to year, but also from century to century, age to age. If granite is at all penetrable by water, is it therefore any wonder that a gradual secular leakage should go on, and at length, by a kind of slow perspiration of the stone, give rise to sufficient accumulation of steam beneath the crust to produce a swelling of the saturated mass, and require a readjustment of the overlying rocks? Now it happens that: by nature all the granitic rocks are crystal- line, and thus somewhat coarse-grained in structure; so that they absorb water from the ground and moisture from the air. The crystalline structure permits penetrability to a greater degree than would fine-grained and very hard rocks such as agate; but no rock has such fine pores as the metals, and especially vitreous bodies like glass, to which agate is an approximation. And as all the metals are proved by experiment to be leaky under great fluid pressure, and glass is shown to obey the same law, it obviously follows that all rocks are leaky under great fluid pressure. Consequently under the incessant pressure of the oceans water must make its way into the heated layer just beneath the earth’s crust- Heretofore the possibility of earthquakes cracking the ocean bottom has been generally recognized, but it has been held that *This statement is perhaps too positive, for Sir William Ramsay, the celebrated British Chemist and Physicist, writes me that he has long be- lieved that the ocean bottom leaks and that the formation of minerals takes place chiefly in the bed of the sea. Undoubtedly this view will come to be generally accepted. Similar views seem to be held by Lord Rayleigh, Sir Wm. Huggins, Arrhenius and many other eminent physicists. 162 SEE—FURTHER RESEARCHES ON [April 4; crevices thus formed would not extend over five or six miles deep before they would be closed by the effects of pressure, which nat- urally increases rapidly as we descend into the earth. The belief has therefore prevailed that although the bed of the sea might be rent by an earthquake, it would immediately close up again, and water would thus be prevented from entering the bowels of the globe. It scarcely seems to have occurred to investigators to consider the effects of the constant hydrostatic pressure resulting from the depth of the sea, in forcing the water slowly through the fifteen miles of granite composing the earth’s crust. A crevice is small, and would let in but little water when closed up quickly; but the whole sea bottom is large, and unless it is really water-tight, even a slow leakage over a large area would at length develop stresses beneath which would necessitate a readjustment of the overlying blocks of the crust. This readjustment is ordinarily called an earthquake. Moreover the great abundance of submarine earthquakes has been largely overlooked by previous investigators. It is the secular effect of the constant pressure of the oceans and of capillary forces in promoting the downward movement of the water which has been generally lost sight of. But if we admit on the basis of experimental evidence that water can penetrate thin layers of granite, the question naturally arises: Can it also penetrate a layer of granite fifteen or twenty miles thick? It seems obvious that it can, because for small or moderate pressures water is nearly incompressible and would not sensibly increase in density as it went down into the globe. The fluid which passed through the upper layer of granite would there- fore keep on descending, under the increasing fluid pressure from above, and at length the whole layer would be saturated, and per- spiring below with a steady leakage which would give rise to tre- mendous steam power in the underlying molten rock. Thus great stresses due to slow accumulation of steam would develop in the layer just beneath the crust, and this would give rise to earthquakes and mountain formation. 5 Among the practical men of science to whom the problem of ocean leakage was submitted, we might name some of the most “thee oily iT” abnatet stenititealiliaiiaintinane od yaiNibqu ni veolavpderes yd tuo geb tao modal GOL side xkon oni! Mommas str Daaeaodiin 000, denb xsomaisaed-onds od dog odd ti cadaganaqoob sch, gaiwods q 7 \ il Aa f } - It * EG SPOS HE I > ae 0 a Day tn Ne Mere 9g eR Rakiy ieNRE. he det i nghenntil ira lvlubinnage yercher Be Ve een hah nr Ada mle ade eg yield Bebbho wd yhose ‘bal etauads motiod ase ods ni W290 esoumdra a? Mpocaddingie tesrhyint oth) Yo bteenousiqanoo-yi9% ai yrevswod' gags pas as rule ag ne Bur spewsverenoerree Wf agp Fatal El simian oreMheig09 ¢) wobsol | xo slau peltt init sitio eid: ssc atgainest eon | aang satteoda Nedexawpdiies ins adi bo sonslaveng otf op.boristdo 1998.] THE PHYSICS OF THE EARTH. 169 Therefore all these islands were formed by the expulsion of lava from under the sea, and the subsequent sinking of the sea bottom has given rise to the deep troughs now found in that part of the ocean, . In the same way there is an earthquake belt between Samoa and New Zealand, and the sea bottom is sunk down into a deep trough, parallel to a ridge on the west, on the opposite side of the trench from the ocean. This ridge is a new mountain rangé 1,200 to 1,500 miles long, now forming on the west of the Pacific, just as the Andes were once formed on the east. Lava is being expelled from under the trench and pushed from the ocean towards the ridge on the west. This is developing into a new mountain range, which we shall call the Antandes, because it is being formed opposite to the Andes, on the other side of the Pacific, and in the same manner as the mighty mountains in South America were in earlier geological time. In the course of immense ages the Antandes will rise above the water as a mighty chain on the west of the Pacific just like the Andes on the east. These phenomena in the sea bottom show the real process of mountain formation at various stages of its progress, and prove to us that most of the folding observed in our mountain ranges now on land really took place in the bed of the sea, long before the whole range was raised above the water. For this sinking and upheaval of adjacent portions of the sea bottom would crumple the rocks exactly as they are observed to be in all mountain ranges; and moreover the several parallel ranges so often observed would result from the development of several parallel troughs, all of which are eventually uplifted. It will be observed that the expulsion of lava is always from the sea towards the land, and this shows that the sole cause of the movement is the leakage of the ocean. It thus follows that mountains, plateaus, and islands are uplifted by earth- quakes depending on the leakage of the oceans, and by nothing else. §7. The Andes with their high Plateaus Merely a Vast Wall Erected by the Pacific.—It may sound strange to say that the cordil- lera of the Andes is a vast wall erected by the Pacific Ocean along its border; but to the navigator who traverses the shore from Pan- ama to Cape Horn such a description will seem most appropriate. 170 , SEE—FURTHER RESEARCHES ON \ [April 24, Fic. 1. Relief Map of South America. (From Frye’s Complete Geog- raphy, by permission of Ginn & Co., Publishers.) Notice that the Andes are a mighty wall erected by the Pacific Ocean along its border. Professor Charles Burkhalter, Director of the Chabot Observatory, Oakland, kindly suggested the use of these relief maps, which are well suited for bringing out the leading characteristics of the different continents. 1908 ] THE PHYSICS OF THE EARTH. 171 Throughout the length of the continent the mountains are every- where parallel to the coast, and run at nearly a constant distance from the shore. The Andes are not always a simple chain, but they are narrow relatively to their height, as compared to the other mountains. In many places there are two or more ranges with narrow plateaus between. These plateaus are so interwoven with the mountains themselves that we may feel sure they were formed together and represent a part of one general movement. Unless this were so it is impossible to believe that so many narrow and high plateaus would be enclosed between mountain walls on either side. The eastern cordillera is less volcanic than the western, and the eastern slope is believed by Professor Solon I. Bailey of Harvard College Observatory, who has exceptional opportunities for judging of these mountains, to be two or three times steeper than the western slope. If we suppose a sea trough was first dug out in the elevation of the eastern range, and eventually when deep sediments had ac- cumulated in the trough, the western edge of it was folded up to form the western range, and the trough itself became the plateaus, we shall have very nearly a true picture of how the Andes were formed. The full details of this process cannot be given now, but there is no doubt that the Andes are a vast wall erected by the Pacific along the edge of the continent. This origin of these mountains is also indicated by the earthquakes observed within historical time; for the coast has been again and again upraised by these disturbances, while the sinking of the sea bottom, indicated by the accompanying seismic sea waves, shows that the bed of the ocean is being undermined by the expulsion of lava under the land. The shells, fossils, and other evidences of marine life now found at altitudes as high as 15,000 feet show that the uplifting at present going on is but a part of the greater uplift of past geological ages; so that the great movement which formed these mountains and pla- teaus is identical with the earthquake disturbances noticed within historical time. $8. The uplift of mountains and’ plateaus around the margins of the Pacific, and of islands in the interior, with innumerable sub- marine eruptions everywhere, is nature’s way of indicating leakage 172 SEE—FURTHER RESEARCHES ON [April 24, through twenty miles of crust—The peculiar position of the sea bottom between a molten globe and the overlying ocean is such that any disturbance of the bottom, as in a volcanic eruption, would naturally excite our suspicions that the crust had leaked and brought the water into contact with the underlying ball of fire. The situa- tion of the overlying ocean, with the fire so close beneath, is much the same as that of the water above the furnace of a boiler, in which steam is developed; and if one had the molten globe for a furnace and the ocean for a reservoir of water, leakage would develop steam on a grand scale, and give rise to mighty experiments exactly resem- bling earthquakes and volcanic eruptions. Some of these disturb- ances might take the form of uplifts of the crust into islands, mountains and submarine volcanoes, others near the edges of the sea would cause lava to push out under the land and raise the coasts. Now the Pacific Ocean is everywhere surrounded by high moun- tains, as if the lava had been pushing out at the margins of the sea. And throughout the interior a vast number of islands are raised up in deep water, and every part of the ocean is from time to time dis- turbed by terrible earthquakes. One must therefore admit that the ocean has the aspect which might be expected to result from a leak- age of the ocean bed. Moreover the Pacific is surrounded nearly everywhere by volcanoes, which emit chiefly vapor of steam. If it is shown that mountains are formed by earthquakes, chiefly in the expulsion of lava under the land, and some of the mountains break out into volcanoes, then there will obviously be a connection not. only between earthquakes and volcanoes, but also between the vapor of steam emitted from these smoking mountains and that formed under the ocean by the leakage of the bottom. It is this intimate connection between all the related phenomena which tells so powerfully in favor of the view that the leakage of the ocean takes place through a layer of rock twenty miles thick. The height of the mountains and plateaus is but a small fraction of the thickness of the crust, and movement in the underlying layers therefore usually gets relief without breaking through. The crust of the globe is thick enough to offer great resistance to uplift, so that the steam saturated lava usually adjusts itself beneath without a surface eruption. Yet where the crust is sharply upheaved as in 1908.] THE PHYSICS OF THE EARTH. 173 mountains, volcanoes sometimes break out. But it is obvious that earthquakes are the more general, volcanoes the more special phe- nomena; and that both are connected with mountain formation, and depend on the sea for their continued activity. § 9. On the Structure of Granite as a Typical Crystalline Rock of the Earth’s Crust—Granite has a thoroughly crystalline structure, and is an admixture of feldspar, mica, and quartz. The mica is in the form of minute shingles, or snowflakes, embedded in the non- crystalline matrix of quartz, which encloses the other elements. The feldspar is chiefly orthoclase. The two chief ingredients, quartz and feldspar, form a granular aggregate made up of grains of fairly equal size, varying all the way from several inches in diameter to a structure so fine as to be inseparable to the naked eye. “Many granites contain irregularly shaped cavities (miarolitic structure), in which the component minerals have had room to crystallize in their proper forms, and where beautifully terminated crystals of quartz and felspar may be observed. It is in these places also that the accessory minerals (beryl, topaz, tourmaline, garnet, orthite, zircon and many others) are found in their best forms. Not improbably these cavities were some- what analogous to the steam holes of amygdaloids, but were filled with water or vapour of water at high temperature and under great pressure, so that the constituents could crystallise under the most favorable conditions. Among the component minerals of granite, the quartz presents a special interest under the microscope. It is often found to be full of cavities con- taining liquid, sometimes in such numbers as to amount to a thousand millions in a cubic inch and to give a milky turbid aspect to the mineral. The liquid in these cavities appears usually to be water, either pure or con- “taining saline solutions, sometimes liquid carbon-dioxide” (p. 143). (Sir A. Geikie, “ Geology,” p. 204.) The cavities in crystalline rock such as granite may contain either gas or liquid matter, and sometimes both. Professor Tilden’s researches have shown that the included gases (hydrogen, carbon dioxide, carbon monoxide, marsh gas, nitrogen, and water vapor) may exceed many times the volume of the rock itself. The cavities have all manner of forms, branching, oblong, curved, oval, spherical and negative crystalline shapes, and are often so numerous as to give a turbid aspect to the mineral. The intersecting planes of the crys- talline granite frequently present real fissures more or less filled with liquid. Obviously capillary forces may here attain great importance, and fluid entering the rock would be absorbed into these spaces PROC, AMER, PHIL, SOC, XLVII, 189 L, PRINTED SEPTEMBER 21, 1908, 174 SEE—FURTHER RESEARCHES ON [April 24, with irresistible power. Geikie remarks that the cavities in quartz have all sizes from the coarse pores visible to the naked eye to minute spaces less than 1/10,000 of an inch in diameter, which can be seen only under high magnifying power. Now it is worth while to remember that small as are the least cavities and fissures which we can see with the microscope, they are very large and coarse compared to the molecular structure of a fluid such as water or of a solid like glass. It is useful to remember that the limit of naked eye vision is about 1/250 of an inch, and of the most powerful microscope about 1/100,000 of an inch. The micro- scope therefore increases our power of vision about 400 times. (Cf. Prof. A. A. Michelson’s “ Light Waves and their Uses,” p. 30.) § 10. On Lord Kelvin’s Determination of the Size of Atoms.— In order to form a clear conception of the physical constitution of the matter composing the crust of the globe, we must recall the lines of research by which Lord Kelvin has determined the size of atoms. 1. By determining the work done or heat produced in bringing thin. plates of zinc and copper together. The observed amount of heat evolved when the plates are made of given thickness and after- wards imagined to be thinner and thinner, limited only by the con- dition that the mass shall not be melted, under the heat of combina- tion, which is not indefinitely great even when brass is produced by fusing zinc and copper, but corresponds to the mutual attraction of a number of plates not more numerous than 100,000,000 to the milli- meter ; hence it follows that the molecules are at least 1/1,000,000,000 cm. and probably more than 1/400,000,000 cm. in diameter. Lord Kelvin concluded that “ Plates of zinc and copper 1/300,000,000 of a centimeter thick, placed close together alternately, form a near approximation to a chemical combination if indeed such thin plates could be made without splitting atoms.” He fixed 1/1,000,000,000 of a centimeter as the minimum diameter of the atoms found in this way. It is to be remembered here that 2.54 centimeters = 1 inch. 2. By the study of Newton’s rings on soap bubbles as they become thinner and thinner, the thickness of the film being reckoned from the known wave-length of the reflected light. Unless the film materially weakened when a certain limit is attained, it could not be stretched beyond a certain thickness without volatilizing, if 1908, ] THE PHYSICS OF THE EARTH. 175 maintained at the same temperature; for as it expands it cools, and the heat that would have to be supplied to it would be more than sufficient to vaporize it. Now it is found by observation that the intensity of the surface tension of the film of water falls off before the thickness is reduced to 1/200,000,000 cm., and hence there prob- ably are but few molecules in that thickness. 3. By the phenomenon of dispersion in the wave theory of light. Cauchy showed that dispersion of colors implied a granular structure in refracting media, and that the grains could not be indefinitely small, but must exceed 1/10,000 of the shortest wave length; and to produce the observed effect Lord Kelvin concluded that the number of molecules in a wave length would have to be from 200 to 600. Nobert ruled lines on glass at the rate of 40,000 to the centimeter,? or about two to the wave length of blue light (about 4/100,000 centimeter) ; and as this left the ruled surface capable of reflection, the number of molecules in the ridges between the grooves must have been sufficient to give solid body to the sculptured mass, and thus not less than several hundred to the wave length. If the mean free path in a solid like glass be 25 times the diameter of the atom itself, this will make the diameter of the atoms of the order of 1/400,000,000 of a centimeter. 4. By calculating the length of the average free path of a mole- cule in a gas, according to the kinetic theory. Loschmidt in 1865, Stoney in 1866, and Lord Kelvin in 1870, independently reached similar results, namely, for the average free path about 1/100,000 of a centimeter, and for the diameter of the gaseous molecule about 1/500,000,000 of a centimeter. These four methods of estimating the diameter of atoms thus agree very closely among themselves; and moreover a similar result on the average distance of molecules deduced by entirely different ? Referring to Nobert’s lines Maxwell says: “A cube, whose side is the 4ooth of a millimetre, may be taken as the minimum visible for (microscopic) observers of the present day. Such a cube would contain from 60 to I00 million molecules of oxygen or nitrogen” (cf. The article “ Atom,” Ency- clopedia Britannica, ninth edition, p. 42). If there be 400 molecules in a line the length of the edge of the cube just considered, the cube would con- tain 64,000,000, which agrees with Maxwell’s estimate. A line equal to the wave length of blue light would thus contain 250 molecules. 176 SEE—FURTHER RESEARCHES ON [April a4, considerations was obtained by M. Lippmann, in a paper read to the Paris Academy of Sciences, October 16, 1882. In his “ Popular Lectures and Addresses” (vol. 1, p. 224) Lord Kelvin condenses his conclusions as follows: “The four lines of argument which I have now indicated lead all to substantially the same estimate of the dimensions of molecular structure. Jointly they established, with what we cannot but regard as a very high degree of probability, the conclusion that, in any ordinary liquid, transparent solid, or seemingly opaque solid, the mean distance between the centres of contiguous molecules is less than the 1/5,000,000 and greater than the 1/1,000,000,000 of a centimetér. “To form some conception of the degree of coarse-grainedness indi- cated by this conclusion, imagine a globe of water or glass, as large as a football,’ to be magnified up to the size of the earth, each constituent mole- cule being magnified in the same proportion. The magnified structure would be more coarse grained than a heap of small shot, but probably less coarse- grained than a heap of footballs.” : § 11. On the Molecular Constitution of Matter and on the Pene- trability of Solids by Fluids—In his address on “ Mathematical Physics ” at the St. Louis Congress of Arts and Sciences in 1904, Poincaré speaks of the porosity of matter as follows: “The astronomical universe consists of masses, undoubtedly of great magnitude, but separated by such immense distances that they appear to us as material points; these points attract each other in the inverse ratio of the squares of their distances, and this attraction is the only forge which affects their motion. But if our senses were keen enough to show us all the details of the bodies which the physicist studies, the spectacle thus disclosed would hardly differ from the one which the astronomer contemplates. There too we should see material points separated by intervals which are enormous in comparison with their dimensions, and describing orbits according to regular laws. Like the stars proper, they attract each other or repel, and this attraction or repulsion, which is along the line joining them, depends only on distance.” (Cf. Bulletin of the American Mathematical Society, February, 1906, p. 241; authorized translation by Professor J. W. Young.) Professor Sir G. H. Darwin’s recent presidential address to the British Association for the Advancement of Science at Cape Town, 1905, was devoted largely to the discovery of electrons. After treating of these subatomic corpuscles he adds: “T have not as yet made any attempt to represent the excessive minute- ness of the corpuscles, of whose existence we are now so confident; but, as an introduction to what I have to speak of next, it is necessary to do so. *Or say a globe of 16 centimeters diameter. 1908. ] THE PHYSICS OF THE EARTH. 177 To obtain any adequate conception of their size we must betake ourselves to a scheme of threefold magnification. Lord Kelvin has shown that if a drop of water were magnified to the size of the earth the molecules of water would be of a size intermediate between that of a cricket ball and of a marble. Now each molecule contains three atoms, two being of hydrogen and one of oxygen. The molecular system probably presents some sort of analogy with that of a triple star; the three atoms replacing the stars, revolving about one another in some sort of a dance which cannot be exactly described. I doubt whether it is possible to say how large a part of the space occupied by the whole molecule is occupied by the atoms; but perhaps the atoms bear to the molecule some such relationship as the molecule to the drop of water re- ferred to. Finally, the corpuscles may stand to the atom in a similar scale of magnitude. Accordingly, a threefold magnification would be needed to bring these ultimate parts of the atom within range of our ordinary scales of measurement. “The community of atoms in water has been compared with a triple star, but there are others known to the chemists in which the atoms are to be counted by fifties and hundreds, so that they resemble constellations.” Such general discussions by these illustrious physicists, Kelvin,* Poincaré and Darwin, are not to be construed too literally, and yet they clearly indicate the general belief among the foremost men of science that the spaces between the particles of matter are im- mense in comparison with the dimensions of the particles themselves. From Lord Kelvin’s discussion of the size of atoms treated in the above section, we have seen that the diameters of these bodies is of the order of 1/500,000,000 of a centimeter, or 1/1,2'70,000,000 of an inch. The average space between the molecules being 1/100,000 of a centimeter, or about 5,000 times the diameter, is of the order of 1/254,000 of an inch. This is decidedly below the *In a well-known paper on gravitating matter, Lord Kelvin compares the stars of the Milky Way to the atoms of a bubble of gas. For a giant for whom our suns would be what atoms are to us, the stars would be beyond the reach of the keenest vision and the Milky Way appear to behave as a gaseous medium. M. Poincaré has discussed the problems of the universe from this point of view in an address to the Astronomical Society of France (Bulletin Astronomique de la Societé Astronomique de France, April, 1906; an excellent translation in Popular Astronomy for October, 1906). It is remarkable that Democritus, founder of the atomic theory among the Greeks (460-360 B. C.), should also have recognized that the Milky Way is composed of a mass of stars too dense to be seen separately by the unaided vision (cf. “ Aristotle’s Meteorology,” Lib. I, Ch. VIII., Sec. 4). Thus Lord Kelvin’s conceptions do not differ greatly from those of Democritus of Abdera, though the modern theories are much better established than the atomic theories were among the Greeks. 178 SEE—FURTHER RESEARCHES ON [April 24, limit of resolution of the microscope which has been estimated by Michelson at 1/100,000 of an inch. Now in our discussion of the constitution of granites we found that the visible pores in the quartz matrix have all diameters down to less than 1/10,000 of an inch, and thus practically to the lowest limit visible in the microscope. These visible pores thus evidently connect directly with the smaller invisible spaces which separate the molecules. As the diameters of the molecules in water vapor are only about 1/5,000 of the spaces between them, the triple atom of hydrogen and oxygen constituting water or water vapor would have ample facilities for penetrating a spongy and cavernous mass like granite with innumerable holes frequently of large size but always at least equal to the average free path. If the water or vapor were under pressure, so as to condense the fluid and thus increase the number of vibrations of a molecule per second, the rate of penetra- tion of the fluid obviously would be much augmented. And since granite not only is filled with pores of these various sizes, but also everywhere more or less cleft by planes of crystalline structures which are not really tight, but full of fissures and thus inviting the penetration of the fluid by the full power of capillary forces, we see that water would necessarily penetrate it at a fairly rapid rate. At the same time the influence of capillarity in such a structure is so great that although water might enter and slowly pass through it, even the development of steam pressure beneath the layer would not force the fluid back, because the steam pressure is nullified an infinitely small distance from where it is exerted, on account of capillary resistance; yet the fluid may keep on descending under the suction of the capillary forces so long as the supply from above is not cut off. Upon these physical grounds it seems clear that there must be a secular leakage of the ocean bottoms, and a corresponding develop- ment of steam beneath the earth’s crust. The steam expands the rock in which it is absorbed and in seeking release thus brings on earthquakes and mountain formation. Even if the pressure due to depth should tighten up the struc- ture of the rock in the lower layers of the crust, it would not be able to obliterate the leakage depending on the pores and crystalline 1908] THE PHYSICS OF THE EARTH. 179 structure. It is evident that at depths such as twenty miles the downward movement of the fluid would continue, though very slowly. Hence the leakage of the oceans is extremely gradual, and the recurrence of earthquakes visibly delayed after relief has once been obtained. Thus while the tightness of the earth’s crust due to the grain of the rock and the pressure to which it is subjected in the lower parts does not prevent ocean leakage, it makes the process so slow and gradual as to afford considerable protection to life upon our planet. II. On THE PHYSICAL STATE OF THE EARTH’S INTERIOR, ON THE AVERAGE RIGIDITY OF THE GLOBE AS A WHOLE, AND ON THE SUBSTRATUM OF PLastic MATTER BENEATH THE CruUST WHICH IN EARTHQUAKES BE- HAVES AS FLuIp. § 12. On the Theory of a Fluid Globe Held by the Older Geolo- gists, and on Hopkins Argument for Solidity Based on the Phe- nomena of Precession and Nutation.—In the early part of the nine- teenth century it was generally believed by geologists that the earth was a liquid globe covered by a rocky crust much thinner in pro- portion to the diameter than the shell is to that of an egg. This supposed liquid interior had been suggested by the streams of molten lava often observed to issue from volcanoes, and by the igneous rocks so abundantly poured forth in many places. The theory of a fluid globe seemed to be confirmed by the observed increase of temperature downward, which would give rise to molten rock at a depth of some twenty miles. The mountains and other phenomena traceable to dislocations of the crust could all be explained by a solid layer of this thickness, and the natural inference was that the great central nucleus remained liquid. The consolidation of the globe was ascribed to the progress of secular cooling, from the primitive state of high temperature assumed by Laplace in the nebular hy- pothesis postulated for explaining the origin of the solar system. The older geologists had not adequately considered the effects of pressure in augmenting the solidity of the globe as we go down- ward; for since pressure raises the melting point of solids, the matter of the nucleus, though highly heated, might be solid if the 180 SEE—FURTHER RESEARCHES ON [April 24, pressure be great enough to prevent fusion under the prevailing temperature. In order to throw light upon this question, Hopkins of Cambridge, England, took up the problem in 1839 (Phil. Trans., 1839; “ Researches in Physical Geology,” 1839-1842), and sought to prove from the observed phenomena of precession and nutation that the earth could not be composed of a thin shell some twenty miles thick, filled with liquid. He concluded that the crust could not be less than 800 to 1,000 miles thick, and that the globe might even be solid to the center, except some small vesicular spaces here and there filled with molten rock. ' In 1868 this subject was examined by the eminent French as- tronomer, Delaunay, who published a paper on “ The Hypothesis of the Interior Fluidity of the Globe” (C. R. Acad. des Sci., Paris, July 13, 1868), in which he threw doubt on the views of Hopkins, and suggested that if the earth’s nucleus were a mass of sufficient viscosity it might behave as if it were solid, and hence concluded | that the observed phenomenon of precession and nutation did not necessarily exclude a fluid nucleus. § 13. Lord Kelvin’s Earliest Studies on the Precession of a Spheroid Containing Liquid——Lord Kelvin had already taken up the problem of the internal state of the earth in 1862, and considered the effects of a fluid nucleus enclosed in a thin shell when the whole mass was subjected to tidal strains. As the shell must yield under these strains the land would be carried up and down with the super- jacent sea, and if such yielding occurred it ought to be sensible to observation. But since the sensible obliteration of the tides had not been observed, he naturally inclined to the view of Hopkins that the earth is effectively rigid and behaves as a solid globe. In reply to Delaunay’s criticism Lord Kelvin pointed out that if the French astronomer had worked out the problem mathematically he could not fail to see that the hypothesis of a viscous and quasi- rigid interior “breaks down when tested by a simple calculation of the amount of tangential force required to give to any globular portion of the interior mass the precessional and nutational motions which, with other physical astronomers, he attributes to the earth as a whole.” (Nature, February 1, 1872.) On making this calcula- tion Lord Kelvin found that the earth’s crust down to depths of 1908. ] THE PHYSICS OF THE EARTH. 181 hundreds of kilometers must be capable of resisting a tangential stress of nearly 0.1 of a gramme weight per square centimeter ; this would rapidly draw out of shape any plastic substance which could be properly called a viscous fluid. “ An angular distortion of 8” is produced in a cube of glass by a distorting stress of about ten grammes weight per square centimeter. We may therefore safely conclude that the rigidity of the earth’s interior or substance could not be less than a millionth of the rigidity of glass without very sensibly augmenting the lunar nineteen yearly nutation.” (Nature, February 1, 1872, p. 258.) Notwithstanding these early criticisms of Delaunay’s paper, Lord Kelvin subsequently concluded that the phenomena of precession and nutation do not decisively settle the question of the earth’s in- ternal fluidity. Yet the semiannual and lunar fortnightly nutations may be considered to disprove absolutely the existence of a thin rigid shell full of liquid. If the fluid were arranged in successive layers of equal density, the only nutational or precessional influence exerted upon it would depend on the non-sphericity of the shells. “A very slight deviation of the inner surface of the shell from perfect spher- icity would suffice,’ according to Lord Kelvin, “in virtue of the quasi-rigidity due to vortex motion, to hold back the shell from taking sensibly more precession than it would give to the liquid, and to cause the liquid (homogeneous or heterogeneous) and the shell to have sensibly the same precessional motion as if the whole constituted one rigid body.” «Sir W. Thomson, British Assoc. Report, 1876, Sections, p. 5.) It will be seen from this discussion that the argument from precession and nutation is only in part conclusive. If the fluid had a viscosity approaching high rigidity for rapidly acting forces, or it were subjected to such pressure that the particles in confinement acquired the properties of a solid, there would evidently be no sensible deviation from the precession and nutation appropriate to a cold solid globe. § 14. On Lord Kelvin’s Researches on the Earth's Rigidity Based on the Analysis of the Tides——The state of the earth’s in- terior had early engaged the attention of Lord Kelvin, for the propagation of heat through the crust was before him as early as 182 SEE—FURTHER RESEARCHES ON [April 24, 1846. (“De Motu Caloris per Terre Corpus,” read before the faculty of the University of Glasgow in 1846; also a “ Note on Cer- tain Points in the Theory of Heat,” February, 1844, published in the Cambridge Mathematical Journal, and reprinted in the “ Mathe- matical and Physical Papers of Sir W. Thomson,” 1882, Vol. I, Art. X.) In a paper “On the Rigidity of the Earth” published in the Philosophical Transactions of the Royal Society for May, 1862, Lord Kelvin pointed out that if the matter of the earth’s interior yielded readily to the tidal forces arising from the attraction of the sun and moon, the crust itself would respond to these forces in much the same way as the waters of the sea; and the corresponding movements of the crust would mask or largely reduce the height of the oceanic tides calculated for a rigid earth. By actual analysis of long series of tidal observations Kelvin and Darwin subsequently found the observed fortnightly tide to have very nearly its full theoretical height, and hence concluded that our globe as a whole possesses a very high effective rigidity. (Cf. Thomson and Tait’s “ Natural Philosophy,” Vol. I, part II, § 832-847; also the article “ Tides,” Encyclopedia Britannica, ninth edition, § 44.) Owing to the great importance of this work on the rigidity of the earth, we must trace the successive steps in the advancement of our knowledge. The assumption that the earth is made up of a liquid nucleus covered with a thin crust stiff enough to maintain its figure against the tide-raising forces of the sun and moon would imply that the crust has a degree of strength and rigidity not pos- sessed by any known substance. It was therefore inferred by Lord Kelvin as early as 1862 that the crust might be 2,000 to 2,500 miles thick, in order to resist distortion under the tide-producing forces arising from the sun and moon. “If the crust yielded perfectly, there would be no tides of the sea, no rising and falling relatively to the land, at all. The water would go up and down with the land, and there would be no relative movement; and in pro- portion as the crust is less or more rigid the tides would be more or less diminished in magnitude. Now we cannot consider the earth to be absolutely rigid and unyielding. No material that we know of is so. But I find from calculation that were the earth as a whole not more rigid than a similar globe of steel the relative rise and fall of the water in the tides would be only 1908.] THE PHYSICS OF THE EARTH. 183 two-thirds of that which it would be were the rigidity perfect; while, if the rigidity were no greater than that of a globe of glass, the relative rise and fall would be only two-fifth of that on a perfectly rigid globe. “Imperfect as the comparison between theory and observation as to the actual height of the tides has been hitherto, it is scarcely possible to be- lieve that the height is only two fifths of what it would be if, as has been universally assumed in tidal theories, the earth was perfectly rigid. It seems, therefore, nearly certain, with no other evidence than this afforded by the tides, that the tidal effective rigidity of the earth must be greater than that of glass. This is the result taking the earth as a globe uniformly rigid throughout. That a crust fifty or a hundred miles thick could possess such preternatural rigidity, as to give to the mass, part solid and part liquid, a rigidity as a whole, equal to that of glass or steel is incredible; and we are forced to the conclusion that the earth is not a mere thin shell filled with fluid, but is on the whole or in great part solid.” (Paper read to Geological Society of Glasgow, February 14, 1878; Kelvin’s “ Popular Lec- tures and Addresses,” Vol. II, pp. 317-318.) In his presidential address to the Mathematical and Physical section of the British Association at Glasgow, September 7, 1876, Lord Kelvin remarked of the earth’s crust that “were it of continuous steel and 500 kilometers thick, it would yield very nearly as much as if it were india rubber to the deforming influences of centrifugal force and of the sun’s and moon’s at- tractions.” “The solid crust would yield so freely to the deforming influence of sun and moon that it would simply carry the waters of the ocean up and down with it, and there would be no sensible rise and fall of water relatively to the land.” (“ Popular Lectures,” Vol. II., pp. 251-2.) Lord Kelvin’s final conclusion was that “the earth as a whole is certainly more rigid than glass, but perhaps not quite so rigid as steel.” § 15. Darwin’s Researches on the Tidal Method of Evaluating the Earth’s Rigidity—As the natural successor of Lord Kelvin in the researches on the physics of the earth, Professor Sir G. H. Darwin took up the problem of the earth’s internal physical con- dition and confirmed and extended these conclusions by several important lines of inquiry. Darwin’s researches on the bodily tides of viscous and semi-elastic spheroids and on the oceanic tides upon a yielding nucleus tended to strengthen the argument for a high effective rigidity so decidedly that he concluded that “no very considerable portion of the interior of the earth can even distantly approach the fluid condition.” But whilst Darwin’s researches confirmed Kelvin’s conclusions as to the great effective rigidity of the earth, yet a more critical 184 SEE—FURTHER RESEARCHES ON [April ag, examination of the method for calculating the fortnightly tide led to the conviction that Laplace’s argument is regard to the effects of friction was unsatisfactory. That friction would greatly effect the motion of the water in slow ocean currents within a few days was seen to be untenable. In consequence of this defect it turned out that long period tides as short as a fortnight would not enable the physicist to evaluate the rigidity of the earth, though the 18.6 yearly tide, depending on the revolution of the Moon’s nodes, if it can be determined by observation, will eventually give the desired result. The height of this 18.6 yearly tide, however, is only one third of an inch at the equator, and great accuracy will be required for its detection. Acting on the old belief Darwin compared the lunar fortnightly and monthly tides observed for 33 years at various Indian and European ports, with the equilibrium theory, and found that the tide-heights were about two thirds of the theoretical height. Ac- cordingly he remarks: “ On the whole we may fairly conclude that, whilst there is some evidence of a tidal yielding of the earth’s mass, that yielding is certainly small, and the effective rigidity is at least as great as that of steel.” (Thomson and Tait’s “ Nat. Phil.,” Vol. 1, Part II, § 848.) This was written prior to the discovery of the theoretical defect in the method of calculating the height of tides with periods not exceeding a fortnight in duration; yet even after the discovery of this defect it was still possible to infer that tides of long period in oceans such as ours must conform much more nearly to the equi- librium laws than do the tides of short period. ‘‘ Whilst, then, this precise comparison with the rigidity of steel falls to the ground, the investigation remains as an important confirmation of Thomson’s conclusion as to the great effective rigidity of the earth. . . . It ap- pears by numerical calculation on viscous and elastico-viscous tides that in order that the oceanic semi-diurnal tide may have a value equal to two thirds of the full amount on a rigid globe, the stiffness of the globe must be about twenty thousand times as great as that of pitch at freezing temperature, when it is hard and brittle.” (Sir G. H. Darwin, article “ Tides,” Ency. Brit., §§ 44-45.) § 16. On the Rigidity of the Earth as found by Comparing the re 1908. ] THE PHYSICS OF THE EARTH. 185 Observed Period of the Polar Motion Arising in the Variation of Latitude with the Theoretical Eulerian Period Calculated for a Rigid Earth.—The detection of the variation of latitude by Kiistner at Berlin in 1890-91 and the subsequent discussion by Chandler of long series of observations showing that the movement of the pole in the body of the earth has a period of some 427 days, instead of the 305 days long ago inferred from Euler’s theory of the rotation of a rigid spheroid, led Professor Newcomb to point out that this ob- served prolongation of the theoretical Eulerian period indicates some yielding of the matter of the globe under the stresses to which it is subjected by the movement of the pole, and would afford a new method of evaluating the earth’s rigidity. In his well-known paper on the “ Dynamics of the Earth’s Rotation” (Monthly Notices, R. A. S., March, 1892) Newcomb showed that the results already ob- tained decidedly confirmed Darwin’s conclusion that the rigidity of the globe as a whole is comparable to that of steel. The essential point in Newcomb’s explanation is that when the pole changes its position in the body of the globe, the distribution of centrifugal force shifts with respect to the solid earth, which is thus put into a state of stress and must yield to the forces acting upon it, like any other elastic solid body; the periodic deformation _ of the earth’s figure operating to lengthen the period of the free nutation, by an amount depending on the average rigidity of the whole earth. The continued investigation of the variation of latitude carried out at the various international latitude observatories by Albrecht and others confirms this observational result, and the subject has also been examined theoretically by Darwin, Hough, Larmor and others; so that the validity of the method suggested by Newcomb is generally recognized. In 1896 Mr. S. S. Hough treated of the problem in a very thor- ough manner in his well-known paper, “On the Rotation of an Elastic Spheroid” (Phil. Trans., A, 1896). He considered chiefly the case of an incompressible homogeneous spheroid, and was en- abled to show by rigorous methods that the rigidity of the earth in all probability slightly exceeds that of steel. In a remarkable paper “On the Period of the Earth’s Free 186 SEE—FURTHER RESEARCHES ON fApeil ag, ’ Eulerian Precession,”’ read to the Cambridge Philosophical Society, May 25, 1896, Professor Larmor showed how to estimate the effect of the elastic yielding of a rotating solid on the period and character of the free precession of its axis of rotation, and again confirmed the high effective rigidity of the earth from another point of view. The observed prolongation of the Eulerian period is thus fully explained by the imperfect rigidity of the earth’s mass, and the high rigidity thus deduced has naturally strengthened the earlier conclusions of Kelvin and Darwin drawn from the study of the long period tides of the sea. This investigation, like those already cited, gives us only an average effect for the earth as a whole, but does not tell us the law of the distribution of rigidity within the globe. If this law of dis- tribution of rigidity could be found, even approximately, it would be of great interest, because we could then see in what part of the globe the principal part of the yielding takes place; and this would give us a much better understanding of the internal constitution of our planet than heretofore has been considered possible. § 17. Rigidity of the Earth Calculated from the Theory of Gravity, on the Hypothesis that the Distribution of Rigidity in the Globe is Everywhere Proportional to the Pressure.—It has not been supposed by previous investigators that a method could be devised for deducing the rigidity of a body like the earth from the theory of gravity; but in 1905 it occurred to the present writer that such a method could be found if we could adopt a suitable hypothesis for the variation of the rigidity with the pressure. Previous investi- gations of the internal state of the heavenly bodies had justified the law of Laplace as giving an excellent approximation to the law of density for the earth and the rest of the encrusted planets; and the monatomic law had been found most satisfactory for the sun and fixed stars (cf. A. N., 4053). These laws enable one to ob- tain the pressure at every point of the radius of the heavenly bodies. For in several ways Laplace’s law of density is fairly well estab- lished for the earth, and on equally good grounds the density of the sun is believed to conform essentially to the monatomic law. From a study of the laws of density, pressure and temperature within the heavenly bodies it appeared to me (as it had indepen- 2908. | THE PHYSICS OF THE EARTH. 187 dently appeared to Arrhenius five years before) that matter under these extreme conditions must be essentially gaseous; and as it is above the critical temperature, it is made to behave in confinement as an elastic solid. Now in all gaseous masses the density is pro- portional to the pressure so long as the gas remains perfect; and the gas does not cease to be perfect when the temperature is above the critical value, though. it may acquire in confinement the property of an elastic solid if the pressure be great enough to bring the molecules within a distance at which the molecular forces become effective in spite of the high temperature. Thus while the property of rigidity in cold solids depends wholly on molecular forces which prevent deformation, this property for gaseous matter in confinement under such pressure that it acquires the property of an elastic solid, is due wholly to the pressure. The molecular forces giving effective rigidity must increase in proportion to the pressure, or in a higher ratio. If according to hypothesis the matter is made solid by pressure, then the molecular forces resisting deformation in the imprisoned matter thus solidified cannot resist deformation in a less degree than the direct proportion to the pressure on which the solidification de- pends. And any ratio higher than the direct proportionality to the pressure would most likely depend on the temperature. Now the temperature in the earth is supposed to be everywhere such as to make the density conform essentially to Laplace’s law ; and the pres- sure resulting from this law of density gives the matter everywhere the property of an elastic solid, and therefore its molecular proper- ties must correspond to the physical state determined by the laws of density and pressure. It is of course conceivable that some parts of the globe might be relatively more rigid than is required to give solidity, but the effect of this would only increase the average rigidity of the earth as a whole. And since seismological and other observations seem to show that the globe is solid throughout, except a thin layer just beneath the crust, the hypothesis of a rigidity proportional to the pressure will give a true minimum value of the earth’s rigidity. Now on the hypothesis that the density follows Laplace’s law, 188 SEE—FURTHER RESEARCHES ON [April 24, the pressure throughout the earth’s mass is given by the formula (cf. A. N., 4104) p= xe ples? — (Cs), (1 where r is the radius of the earth, g mean gravity, g the constant for Laplace’s law, 2.52896 radians = 144° 53’ 55”.2, o the density at any point, 8 the density at the surface, and o, the mean density. To render this expression available for integration throughout the sphere occupied by the earth’s mass, we must put for o? its value sin’ (gx) a = % Ge ’ and for 8 its value sin’ g & = oc» 7 ’ corresponding to the surface where r==1. Thus we obtain 3(o,Z)7r i= (gx) sin? 4 = 3 2 < ang) bk gx? a (2) For the total pressure throughout a sphere of radius p= rx, r being the external radius, and += (p/r) = fraction of the radius, we have P= i Pp: 40rx-rdx _ 3% 8) 74m? pa} “a? £ ge 2(0,8)9" ( 2 a’dx — sin? g ade), which by integration becomes (3) _ 3(%,8)r4mrr? (= — sin (gx) cos (7%) — 2(0,8)¢" 29 As our integration is to include the whole sphere of the earth, we put += 1, and then we have ~ sintg). 3 3(o, 2) ‘r4mr (9 — sin g cos sin? g Pa 36%8) (- 7COSg . (5) 2(7,8)¢" 2g 3 The total volume of the earth is (4/3)ar*, and hence the average pressure per unit of area on all concentric spherical surfaces is 1908. ] THE PHYSICS OF THE EARTH. 189 P. =i = af Amr x? -rdx 3g Tr 4mr® (6) _ A% 8)? 7 te —singcosg _ sin’ 4 on 29 Bee. If r is expressed in meters, the mean pressure or mean rigidity R comes out in kilograms per square meter. To reduce the result to atmospheres we divide by 10,333. The result for the earth is R = 748,843 atmospheres, about the rigidity of wrought iron. This method takes no account of the earth’s solid crust, and is therefore too small; moreover viscosity increases within the earth, owing to the rise of temperature downward. We give hereafter an approximation to the increase of rigidity by determining the mean rigidity of the earth’s matter, as distinguished from that of the various layers composing the globe, just found by the above analysis. To find the mean rigidity of the earth’s matter we must consider not only the pressure but also the density or mass per unit volume of the imprisoned matter in each layer. The result represents a mean rigidity in which every elementary spherical shell composing the globe is allowed a weight proportional to its mass, which is multiplied by the pressure to which it is subjected. The theory of the determination of the mean rigidity of the earth’s matter is as follows: ‘teal ee 4nrx’ -rdx:o = 4rr*o, [px *d. pe) (7) Substituting for p its value from (2), we get 3(a,2)" r-4mr'o, (oe (gx)xdx a f 2? sin ee, P CG a ae gee ®) _ 3(% £yr-4nr a, ( [= (gx)gax is : {? sin (9x)gdx he 2(9,8)9" 0 9 0 q sin (qr)—qx cos (qv) g? The value of the first integral is most conveniently found by quad- rature, table for which is given in A. N., 4104, p. 379. Dividing out the mass, or volume of the sphere by the density, we have PROC. AMER. PHIL. SOC. XLVI. 189 M, PRINTED SEPTEMBER 22, 1908. The integral of this last term is — sin? q 190 SEE—FURTHER RESEARCHES ON [April 24, i amr'x -rdx-o ~ dro, 41o,r° (10) a ele Hie peat I Bin (oe ee (@2))). On putting gx = 144° 53’ 55”.2, the value of the integral is found by quadrature to be 0.9592502, and when the rest of the formula is reduced to numbers we have (A. N., 4104) : R’ = 1028702 atmospheres. The rigidity of nickel steel is taken to be 1,000,000 atmospheres. It thus appears from this calculation that the average rigidity of all the earth’s matter somewhat exceeds that of nickel steel. The actual rigidity of the earth almost certainly lies between the limits thus established, namely R= 748,843, based on the rigidity of the layers deduced from the pressure to which they are subjected, and R’ = 1,028, 702, derived from the product of the mass of each layer by the pressure acting upon it. In the paper, “ Researches on the Rigidity of the Heavenly Bodies,’ A. N., 4104, the rigidity of the earth is discussed as follows: “When one considers the effects of the enclosing crust and the viscosity of the whole earth, which must be assumed to increase towards the centre, owing to the increasing density and rising temperature of the imprisoned matter, it seems not improbable that the actual effective rigidity of our globe may be nearer the upper limit than the lower, and probably we shall © not be far wrong in concluding that it is approximately equal to that of nickel steel. “Leaving aside the consideration of the effects of the solidified crust, it is evident from the nature of the forces at work that most of the yielding of our globe, due to the periodic action of small forces, is in the outer layers; and in general the yielding in any concentric layer may be taken to be in- versely as the pressure to which the imprisoned matter is subjected. Jt is remarkable that the curve of pressure as we descend in the earth becomes therefore also the curve of effective rigidity for the matter of which the earth is composed. Thus the rigidity of the matter at the earth’s center probably is at least three times that of nickel steel used in armor plate; as we approach the surface the effective rigidity constantly exceeds that of nickel steel until we come within less than 0.4 of the radius from the sur- face, where the pressure is less than 1,000,000 atmospheres. 1908. ] THE PHYSICS OF THE EARTH. 191 “To imagine a mechanical substitute for the earth’s constitution, without the introduction of pressure, suppose an alloy of adamant to give the material at the centre of such a globe, of the same size but devoid of gravi- tation, a hardness three times that of armor plate. The outer layers as we approach the surface must then be supposed softer and softer, until it is like armor plate at a little over 0.6 from the center, and finally a very stiff fluid near the surface. In addition to this arrangement of its effective internal rigidity the actual earth is enclosed in a spheroidal shell of solid rock analogous to granite. One can easily see that tidal forces applied to all the particles of such an artificial armored sphere would produce but very slight deformation, because of the enormous effective rigidity of the nucleus. “The principal uncertainty in this result arises from the admissible variations in the assumed Laplacean distribution of density within the earth. Both Radau and Darwin (cf. Monthly Notices, Roy. Astron. Soc., December, 1899) have pointed out that considerable variations in the internal distribu- tion of density are possible without invalidating the well-known argument drawn from the phenomenon of the precession of the equinoxes; yet on physical grounds it seems clear that pressure is the principal cause of the increase of density towards the earth’s centre. And since this does not vary greatly for moderate changes in the law of density, the principle of con- tinuity shows that the actual law, of density within the earth cannot depart very widely from that of Laplace. The above value of the theoretical rigidity of the earth may therefore be taken as essentially accurate, and I think no doubt can remain that the rigidity of our earth as a whole considerably exceeds that of steel. The original conclusions of Kelvin and Darwin are therefore confirmed by the present dynamical considerations based upon the theory of universal gravitation.” In this connection we should remember that the experimental rigidity of steel is 808,000 and of glass 235,000 atmospheres. The calculated rigidity of all the matter within the globe, found by con- sidering not only all the layers, but also the density in each layer, is found to be 1,028,702 atmospheres. Now the average rigidity must be greater than 750,000, because the stiffness of the crust and increase of viscosity downward is neglected in the gravitational method. In fact this method is not applicable to the outermost layers, because the pressure there is much less than the rigidity, and only becomes equal to the rigidity at a depth of something like one tenth of the radius, where the pressure is 320,295 atmospheres. According to the experiments of Milne and Gray the rigidity of granite is about one sixth that of steel; and as steel has a rigidity of 808,000 atmospheres, that of granite is about 135,000 atmospheres, or a little more than one half that of glass. We may therefore take 192 SEE—FURTHER RESEARCHES ON [April 24, the outer layers of our globe to have a rigidity about half that of glass, and assume that at a depth of 0.1 of the radius it becomes nearly 2.5 times as great as it is at the surface. Whether it becomes at a depth of twenty miles less than it is at the surface we cannot tell, but such a decrease is not impossible, perhaps not improbable; because at this depth the molten rock moves in earthquakes, and yet in confinement it must have a very sensible rigidity, though probably not more than half that of granite. Accordingly, it looks as if the rigidity at the surface is about half that of glass, at a depth of 20 miles about one half that at the surface, and at the depth of 40 miles nearly the same, but increas- ing below that depth and at 160 miles again equal to that at the surface, and at a depth of 400 miles considerably larger yet, or about 1.4 times that of glass. Increasing below this depth according to the pressure, it becomes at the center over 3 times that of nickel steel used in armor plate. The rigidity of steel is attained at a little over 0.3 of the depth‘to the center of the earth. If this be the dis- tribution of rigidity in the earth, the curve of rigidity is as follows: This postulated fall in the rigidity just beneath the crust is probable for several reasons: 1. The temperature increases quite rapidly as we go downward, while the pressure increases proportionately more slowly, so that a depth would be reached at which the matter would become a plastic if not a viscous fluid. | 2. The eruption of volcanoes and lava flows on a vaster scale show that a molten layer underlies the crust, and occasionally is forced to the surface. 3. This underlying molten rock moves in world-shaking earth- quakes, and frequently is expelled from beneath the sea under the land to form mountain ranges along the coast. 4. We may prove this expulsion of lava by the observed seismic sea waves which indicate a sinking of the sea bottom, and by the simultaneous uplift of mountains and coasts. From these considerations it follows that the earth is most nearly liquid just beneath the crust, and has the greatest rigidity at the center. As the plastic or quasi-viscous layer beneath the crust is thin, and possessed of considerable rigidity, it too remains quiescent 1908.] THE PHYSICS OF THE EARTH. 198 except when set in motion by the dreadful paroxysms of an earth- quake, _ In tidal and other observations the earth therefore behaves as a solid, and the rigidity of the earth inferred by Kelvin and Darwin is confirmed. Yet a layer of plastic matter or quasi-viscous fluid exists just beneath the crust, and when disturbed by earthquakes gives rise to the development of ridges in the crust called moun- tains, chiefly by the expulsion of lava from under the sea. Rent Pas ye Uae oe bee : eas ane x me Radii Hagdius 4s "pais! Axis of Rigidity Z. Ler do. fs) fo) of ais ole fe Fic. 2. Curve of Rigidity for the Earth, showing the plastic layer just beneath the crust. § 18. Wiechert’s Researches on the Interior Constitution of the Earth and on the Plastic or Viscous Layer which he Infers to Exist Just Beneath the Crust from Oscillations of Long Period Noticed in Seismic Vibrations—Professor E. Wiechert, of Gottingen, has devoted much attention to the problem of the constitution of the earth’s interior. He long ago reached the conclusion that the great interior nucleus probably is a mass of iron covered with a thick 194 SEE—FURTHER RESEARCHES ON [April 24, shell of stony material. In the paper which he recently presented to the International Seismological Association in session at the Hague, September 21-26, 1907, he estimates the depth of the stony layer as 1,500 kilometers, which is nearly one fourth of the earth’s radius. This view that interior of the earth is metallic has been en- tertained by many eminent physicists, including Lord Rayleigh; but it is beset with many difficulties. We shall here mention three of the principal objections: 1. If this constitution of the earth be admitted, the curve of density will have a sudden break at a depth of about one fourth of the radius; and, as the pressure increases rapidly as we go down- ward, it seems improbable that the density of the outer layer could remain uniform and then change suddenly at a depth of one fourth of the distance to the center. Such discontinuity in nature seems highly improbable for the density, since there probably is no sensible discontinuity in the laws of pressure and temperature. 2. If the central nucleus is metallic, it follows that the denser elements have separated from the rest of the mass. As the matter has been essentially solid and highly rigid, owing to the pressure, ever since the globe attained anything like its present dimensions, this sinking would not be possible, because the resistance to the motion would be much too great. Thus owing to resistance to motion arising from rigidity we can not admit a separation of the denser from the lighter elements of such a globe. If the metals were all so deep down, it would be hard to account for the veins found in the crust by any kind of eruptive process, since the globe is never fissured to a depth of anything like one fourth of the radius. 3. If in addition to these mechanical objections we recall that deep down the pressure is so great as to cause an interpenetration of all the elements, whatever be the temperature, but especially under the high temperature known to prevail in the interior of the globe, so that no aggregation or crystallization of substances would be possible, and the nucleus would therefore be a magma of all the elements, it becomes inconceivable that the metals could separate from the stony elements by sinking, while the latter floated to the 1908. | THE PHYSICS OF THE EARTH. 195 surface. Even if the globe were a liquid mass of very small viscosity, it is clear that such a separation of the elements could not take place. Finally it is to be recalled that recent experiments with radium have shown the probable transmutation of some of the metals, as when Sir Wm. Ramsay caused sulphate of copper to be partially degraded into lithium. If this can occur for one or two metallic elements, it may eventually be possible for many and perhaps all of the metals. Our knowledge of these transformations is still in its infancy, and we can not yet ascertain how minerals and metallic veins have arisen; but it is impossible to believe that the material has come up from a pure supply at a depth of 1,500 kilometers. It is much more probable that the metallic elements have been de- veloped by differentiation and transformation from an original magma, and that the whole interior of our planet is still a magma. Differentiation of the elements appears to develop under conditions met with in the crust, but nowhere else. Accordingly we are obliged to dissent from the constitution of the globe outlined by Professor Wiechert; but in the matter of the existence of a layer of plastic or fluid material just beneath the crust, which he infers from the long seismic vibrations with periods of about eighteen seconds, we are in hearty accord with him. This is definitely proved by the phenomena noticed in earthquakes, as more fully set forth hereafter. It is the expulsion of lava from under the margins of the sea which produces world-shaking earthquakes and the upheaval of mountains along the sea coasts. § 19. On Sir G. H. Darwin’s Researches on the Stresses in the” Interior of the Earth Due to the Weight of Continents and Moun- tains—We have seen that the earth behaves as a solid at all depths, unless it is in the thin layer just beneath the crust, in which move- ments take place during earthquakes. The theory of an elastic solid shows that when such a body is stressed the state of stress is completely determined when the amount and direction of the three principal stresses are known. No limit is imposed on these stresses by theory, but in practice nature fixes a limit, beyond which the elasticity breaks down, and the solid either flows or ruptures by breaking. 196 SEE—FURTHER RESEARCHES ON [April 24, In the “ Nat. Phil.,” Vol. I, part II, § 832, Lord Kelvin and Professor Tait remark that “The precise circumstances under which elastic bodies break have not hitherto been adequately investigated by experiment. It seems certain that rupture cannot take place without difference of stress in different directions. One essential element therefore is the difference between the greatest and least of the three principal stresses. How much the tendency to break is influenced by the amount of the intermediate principal stress is quite un- known. The difference between the greatest and least stresses may however be taken as the most important datum for estimating the tendency to break. This difference has been called by Mr. G. H. Darwin (to whom the investi- gation of which we speak is due) the ‘ stress-difference.’ ” Stress-difference is a term which when applied to matter within the earth denotes the tendency to flow. For rupture is not possible when the matter is in confinement under such pressure and at high temperature. Now if the earth were homogeneous, as assumed in Darwin’s inquiry, the inequalities of surface due to the mountains, plateaus, and continents would give rise to a stress-difference in the underlying layers; and Darwin showed that the stress-difference would increase with the depth, being at the center, for inequalities of the type represented by harmonics of the second order, eight times what it is at the surface. If the earth were not effectively solid throughout, a flow ought to take place either near the surface or at greater depth; and thus the inequalities of surface would disappear. But the plateaus and mountains do not sink in, and this fact proves that the globe is not fluid, and even that the plastic or viscous layer just beneath the crust is quite stiff. As we have seen that the rigidity increases very rapidly towards the center, we easily see why movement should not occur at great depth, since the rigidity there exceeds that of any known substance, and at the centre is about three times that — nickel steel used in armor plate. ” In the paper on the “ Temperature of the Earth ” we have shown from the evidence of stability afforded by geological pinnacles millions of years old, that no movements of deep seated character occur within the earth. This evidence supports the view that the earth is effectively solid, and has behaved as such since the con- solidation of the crust.. 1908.] THE PHYSICS OF THE EARTH. 197 As the rigidity increases so rapidly towards the center of the earth, flow ought not to take place at those depths; and the absence of-any evidence of deep seated movements among the ruins wrought by geological time in turn supports the theory of rigidity depending on the pressure. Darwin’s hypothesis of homogeneity is only a rough approxima- tion to the truth, and Laplace’s law would no doubt give a much more exact representation of the density and the resulting stress- difference in the earth. But this suggested change of data would not greatly modify the general conclusions already stated. § 20. The Theory of Isostacy—A. more important difference might arise from the theory of isostacy, the applicability of which to the earth seems to be becoming better established by recent re- searches. In this view the crustal inequalities seen at the surface are compensated for by lighter or greater densities beneath, accord- ing as the crust is elevated or depressed, so that for a certain thick- ness of crust equal blocks have equal mass, however unequal the level of the blocks at the surface. The recent investigations by the U. S. Coast Survey indicate that the depth of complete compensation for the United States and outlying stations is about 71 miles. No doubt a depth of something like this extent would hold true for the entire globe. If this view be admissible, it will follow that all inequalities of the crust cease to be effective at depths greater than 71 miles, and no stress-differ- ences depending on plateaus and mountains would exist in the globe except in the layers just beneath the crust. There would thus be no stresses in the deep interior depending on the weight of continents and mountains. This theory of isostacy is confirmed by the theory of mountain formation developed in the paper on the “‘ Cause of Earthquakes,” which shows clearly that these elevated ridges are underlaid by material lighter than the average rock of the crust. On the one hand, therefore, if stress-differences exist deep down, no move- ment can take place, owing to rigidity; on the other, if the theory of isostacy be admissible, no stress-differences can exist except in the outer layers of the globe, within 71 miles of the surface. We conclude therefore that in no case could movements occur 198 SEE—FURTHER RESEARCHES ON [April 24, except in the layer just beneath the crust. These superficial move- ments are called earthquakes, and are caused chiefly by the leakage of the oceans. Observations show that the depth of such disturb- ances in all cases is less than 40 miles. This accords with the theory of isostacy, and confirms the conclusions drawn from that theory that all surface inequalities are compensated for at but a slight depth. © : § 21. Uplifts along the Andes show that the mountains are not sinking under their own weight—In Professor Sir G. H. Darwin’s paper on the stresses in the earth, above cited, he has also con- sidered harmonics of high order, corresponding to*the case of a series of parallel mountains and valleys, which thus corrugate a mean level surface with an infinite series of parallel ridges and furrows. Here the stress-difference depends only on the depth be- low the surface, and is independent of the position of the point considered with respect to ridge and furrow. Taking a series of mountains 13,000 feet (about 4,000 meters) above the valley bottoms, formed of granite of density 2.8, he shows that the maximum stress-difference is 4 X I0° grammes weight per square centimeter (about the tenacity of cast tin). And when the mountain chains are 314 kilometers apart, making the ridges about 78 times wider than they are deep, the maximum stress-difference is reached at a depth of 50 kilometers below the surface, or at a depth of 12% times the height of the mountains above the valleys. Thus for mountains of the height of our average ocean depth, the maximum tendency to flow would be at a depth of about 31 miles. (Cf. “ Nat. Phil.,” Vol. I, Part II, § 832.) If earthquake shocks were due to such flowage the mountains would be gradually reduced in height. Instead of this settling oc- curring, mountains like the Andes are still rising, as we may infer from the fact that after an earthquake the adjacent sea coast often is elevated and higher than before; while the sinking of the adjacent sea bottom, indicated by the accompanying seismic sea wave, shows that the bed of the sea was undermined by the expulsion of the material pushed under the land and mountains. This state of fact emphatically contradicts the view that these great seismic disturb- ances are due to the flowage beneath the crust arising from the 1908.] THE PHYSICS OF THE EARTH. 199 weight of continents and mountains. Neither the uplift of moun- tains about the sea coasts, nor the earthquakes occurring in these regions can be explained by flowage beneath the crust, because the movement is positive rather than negative, as required by this theory. Whilst the investigation of Professor Sir George Darwin there- fore does not give us a clue to the observed movements, it is never- theless very valuable as furnishing an indirect confirmation of the present theory that mountain formation depends on the sea. Ob- servation shows that the movements are positive, and as the theory of flowage indicates that they should be negative, we may infer that whatever be the stress-differences existing beneath the earth’s crust, the movements thus produced are insensible compared to those depending on the expulsion of lava from under the sea by world- shaking earthquakes, Ill. THe New Puysicat THrEory oF EARTHQUAKES AND Moun- TAIN FORMATION BASED ON THE SECULAR LEAKAGE OF THE OcEAN BOTTOMS. § 22. On the Plastic and Perhaps Viscous Layers Just Beneath the Earth’s Crust——We have now examined at length the arguments in regard to the constitution of the earth’s interior, and have shown that although as a whole the earth is solid, owing to the pressure to which the matter is subjected, there is a plastic layer just beneath the crust which in earthquakes is made to flow and behave almost as a viscous fluid. In this layer just beneath the crust either the pressure is not great enough to produce entire solidity, with the existing temperature, or else the solid is made to flow by the break- ing down of the elasticity under the action of the earthquake forces, which are powerful enough to disturb the whole world. _ Although the matter in this substratum appears to have some rigidity, it seems probable that it has not the requisite elasticity to behave as a perfect solid. We know that the layer must be nearly solid, because, if it were not so, there would be a greater tendency of the mountains to subside than actually is observed. The stress- difference in the layers just beneath the crust must be very con- siderable; and yet this plastic matter is so stiff that it does not flow and allow the mountains and plateaus to sink in. 200 SEE—FURTHER RESEARCHES ON [April 24, Now earthquake disturbances are often complex, and consist in horizontal and vertical movements combined. We have seen that in the long run the uplifting tendency predominates, because it is in this way that the mountains and plateaus have arisen. Nevertheless there are numerous cases in which subsidences take place, and these settlements often seem to be somewhat gradual, as if the substratum was slowly yielding and flowing under the stresses to which it is subjected. These gradual subsidences, of the class that was observed by Darwin and Fitzroy at Conception in 1835, seem to afford con- vincing evidence that the layer beneath the crust is certainly plastic, perhaps viscous.* The yielding of the layer beneath the crust is shown not only in movements noticed in earthquakes, when lava is expelled from under the sea and pushed under the land; but also in the subsidences which the sea trenches experience after earthquakes. These subsidences have folded the rocks seen in mountain ranges now on land; and although most of such subsidence is due to the undermining of the troughs by the expulsion of lava, it seems likely that some very gradual yielding also takes place. The layer under the crust is therefore certainly plastic, when partially undermined, and probably so, independent of the undermining, if it is subjected to great forces, as in world-shaking earthquakes, where mountains are in process of upheaval. If the matter is also viscous, the viscosity must be very high. With the matter imprisoned beneath the earth’s crust it is difficult if not impossible to distinguish between plasticity and true viscosity, because, if the fluid is very stiff, it would behave almost as a solid. And the tests heretofore afforded by earthquakes are not decisive. This view of the substratum just beneath the crust is not essentially different from the theory held by Arrhenius with re- gard to the interior of the earth as a whole. But this layer is the only part of the interior in which movements may be observed, and even here movements would not take place but for the steam de- veloped beneath the crust by the secular leakage of the oceans. It may be that the future study of these movements will some day *We follow Sir George Darwin in “ distinguishing viscosity, in which flow is caused’ by infinitesimal forces, from plasticity in which permanent distortion or flow sets in when the stresses exceed a certain limit.” (Letter to Sir A. Geikie, January 9, 1884.) 1908.] THE PHYSICS OF THE EARTH. 201 enable us to decide whether the substratum is plastic only, or truly viscous. § 23. Substratum Everywhere Quiescent Except when Disturbed by Earthquakes.—The fact the large areas of the earth’s surface in such dry countries as Sahara, our Western Plateaus, and the interior of Australia, are quite free from earthquake disturbances, shows what would happen everywhere but for the presence of surface water, and especially the leakage of the crust depending on the sea. The quiescence of the substratum in interior regions remote from the sea shows that under normal conditions this layer is quite inert. It is only set in motion by the vapor of steam which slowly develops stresses in the rocks of the crust and finally brings on earthquakes. It might be plastic enough to yield slightly under sufficiently great forces, but the loading and unloading due to meteorological and geological causes going on in nature are not great enough to have any appreciable effect, as we may infer from the universal quiescence of inland areas, especially in desert countries. It seems to be true, however, that when the crust is broken and upheaved, in the formation of mountains near the sea coast, some slow yielding takes place beneath. Yet at present any changes of a creeping nature can not be entirely separated from those depending on the expansion and expulsion of lava from under the sea; and we can only feel sure of the inert character of the substratum, except where disturbed by water vapor entering from without. Along the sea coasts the stresses in the crust are constantly changing, and the crust blocks yielding more or less to the stresses acting upon them; it is only when sudden yielding occurs that we experience a shock, and’ the greatest earthquakes are characterized by molten rock ad- justing itself beneath the crust. It is probable that much yielding takes place which is exceedingly gradual and produces no disturb- ances sensible to ordinary observation. In dry regions remote from the sea there are no shocks, and therefore also no gradual yielding of the crust; hence the substratum is inherently and naturally qui- escent except when disturbed by external forces. § 24. Mountain Formation in the Sea and on the Land.—In the paper on the ‘“‘ New Theory of Earthquakes and Mountain Forma- tion,’ we have cited certain cases of mountain formation now going 202 SEE—FURTHER RESEARCHES ON [April 24, Fic. 3. Relief Map of North America. (From Frye’s Complete Geog- raphy, by permission of Ginn & Co., Publishers.) This map illustrates beauti- fully the recession of the sea since the formation of the Rocky Mountains, which were at one time the eastern border of the Pacific Ocean. 1908 ] . THE PHYSICS OF THE EARTH, 208 on in the depths of the sea, and directly connected with mountain ‘systems spread out on the land. Thus we have shown that the Aleutian Islands are a branch or part of the Rocky Mountains still remaining in the depths of the sea. As this part of the chain is now being uplifted by the ocean, we get a very clear conception of how the whole Rocky Mountain system was formed. We are fortunate therefore to find a part of a great mountain chain still unfinished, with one end under water and the main body of the system high and dry along the edge of the continent. Now no one believest that mountain formation takes place far inland, because the mountains generally follow the coast, and more- over at present the process is found to be most active im the sea, as in the region of the Aleutian Islands and the Antandes. This geographical distribution of mountain-making is therefore a most powerful argument for the new theory. Moreover it is generally recognized that the Rocky Mountains in the United States are a good deal older than the Andes in South America; and as the relative ages bear some relation to the distances from the sea, the mountains on land give the same indication as those still in the depths of the sea. The recession of the sea goes on at very unequal rates in different parts of the world, yet the present positions of the mountains show that the older mountains are generally remote from the ocean. The present theory is therefore confirmed by the lay of the older as well as of the younger mountain systems; and by the situation of the mountains on land as well as of those now being formed in the depths of the sea. All the mountain phenomena of the globe are thus shown to be consistent. But as direct observation of mountain formation witnessed with our own eyes is the most convincing of all evidence, it is fortunate that we are able to cite numerous cases of mountain ranges now developing in the sea. By the study of the sinking going on where trenches are developing, we see how the wrinkles and valleys were produced in mountain systems now at a considerable distance from the ocean. Since the sea recedes from the mountains in the course of geological ages, it follows that more and more land is constantly rising above the water, *Compare § 42 of this paper, where Leconte’s views are quoted at length. He held that mountain ranges are formed on lines of thick sediment along the shores of continents. 204 SEE—~FURTHER RESEARCHES ON [April 24, and the continents growing larger. The mountains are formed by earthquakes, and earthquakes are due to the sea, which thus makes more and more land for the development of the higher forms of life upon the globe. Fic. 4. Relief Map of the United States. (From Frye’s Complete Geog- especially how the great plateau west of the Rocky Mountains has been 1908. ] THE PHYSICS OF THE EARTH, 205 § 25. The Origin of Faults in the Earth’s Crust—lIt has long been recognized that faults in the earth’s crust are often displaced by earthquakes. Now earthquakes are mainly submarine or follow the borders of the continents. Here the mountain ranges have de- raphy, by permission of Ginn & Co., Publishers.) The reader should notice crumpled in the uplift from the sea, which has receded westward 1,000 miles. PROC. AMER, PHIL, SOC. XLV1I. 189 N, PRINTED SEPTEMBER 22, 1908. 206 SEE—FURTHER RESEARCHES ON [April 24, veloped or are now developing, and in general the faults run along the sea coasts and into the sea, where mountain formation is in progress. Thus it is clear that faults arise from the stresses and movements of the crust produced by earthquakes and mountain formation, and therefore from the secular leakage of the ocean bottoms. Sometimes the faults move but little, at other times they give rise to conspicuous changes of level; and where vast down-throws or uplifts have occurred certain types of mountains arise from normal faulting. The more horizontal movements of faults arise mainly in the trenches along the sea coasts, which produce the folding seen in mountain chains. The vertical movements are more general, and are especially conspicuous in elevated plateaus, like those of our western states. In his “ Report on the Geology of the High Plateaus of Utah,” Washington, 1880, Major Dutton gives a description of some of the most magnificent faults in the world. On page 45 he indicates the dependence of these faults on the ancient shore line of the Eocene lake, thus: “Tt yet remains to speak of another interesting relation of the later system of faults. They have throughout preserved a remarkable and per- sistent parallelism to the old shore line of the Eocene lake, following the broader features of its trend in a striking manner. The cause of this rela- tion is to me quite inexplicable, so much so, that I am utterly at a loss to think of any subsidiary facts which may be mentioned in connection with it and which can throw light upon it.” What puzzled Major Dutton most was the raising of the area of the lake; but as the whole region was uplifted by the sea in later times this phenomenon was in no way remarkable. The rocks in such disturbed regions have been broken and folded into a series of troughs and arches or thrown into domes and basins, and probably no two adjacent areas retained their relative levels throughout. His observation, however, confirms the present theory that faulting is generally parallel to the ancient sea shore, and therefore produced originally by the oceans, The conspicuous character of the vertical movement of the crust blocks in the region of the Great Basin led several American geolo- gists to suggest that vertical forces had operated in the uplift of 1908. ] THE PHYSICS OF THE EARTH. 207 these plateaus. As the whole region has been raised from the sea by the injection of the land with lava pushed under the crust from be- neath the sea, it is evident that the crust blocks ought to be displaced unequally in different places, and hence the various types of faulting observed. It should be remarked, however, that in the elevation of a plateau a mile high, only a layer of lava a mile deep needs to be injected. If three miles high, the layer would have to be three miles thick; but even this maximum height is only about one seventh of the thickness of the crust; and hence eruptions would not usually occur ' in these uplifts. The plateaus are all of small height compared to the thickness of the earth’s crust, beneath which the movement of molten rock takes place. If some faults should thus be widely opened, lava flows of vast extent, like those in Utah and Oregon, might be expected to occur. We cannot give the details of the cracks which produced these gi- gantic outflows, but it is evident that they depended on the opening of immense faults. Now the faults are produced and moved by earthquakes, and earthquakes are due to the leakage of the oceans. It follows therefore that the most immense lava flows ought to take place near the sea; and this seems to be true both in North America and in Asia, where the outflow in the plateau of Deccan has always excited the wonder of the naturalist. That all the faults of the earth’s crust depend on the sea and are produced by world-shaking earthquakes, is clearly indicated by the geographical distribution of these cracks in the crust. If any other cause, such as the secular cooling of the globe, were at work, we should find a relatively greater predominance of faults far inland, which is contrary to observation, especially in dry countries. It is remarkable that geologists have referred so many phenomena to faulting, but have made little or no attempt to explain faulting itself. In the present theory referring the origin of faults to the expulsion of lava from under the sea we have for the first time a satisfactory and consistent view of these phenomena. Faults evi- dently arise mainly from the motion of lava in earthquakes, by which the overlying rocks of the crust are broken, and often displaced along the line of fracture. 208 SEE—FURTHER RESEARCHES ON [April 24, When the crust is thus rent into blocks, some of them are re- duced to small size, and eventually raised up, as in the vertical walls of granite now seen in Smyth’s channel, southern Chile, the Straits of Magellan, Yosemite Valley, California, and the fiords of Nor- way. ‘These precipitous walls of granite could be pushed up only by vertical forces, in earthquakes. It is noticeable that no such isolated masses are found towering up in the plains of Kansas, the desert of Sahara, and other inland regions far from the oceans. The origin of faults and fault movements must therefore be sought in the leakage of the oceans and in the resulting relief, which takes place in the sea bottoms and along the borders of the continents. § 26. On the Uplift of the Great Plateaus of the World and on the Gradual Elevation of the Continents.—For reasons already amply set forth in § 7, the process involved in the formation of the Andes is clear and beyond dispute. Now it happens that the Andean pla- teaus, such as those of Quito, Caxamarca, Cuzco and Titicaca, are generally included between the eastern and western ranges of the Andes, and were evidently uplifted by the same forces which formed the mountains themselves. Accordingly it is clear that a plateau such as that of Titicaca was therefore uplifted by the expulsion of lava from under the sea. If now we pass from the Andes to the Himalayas, we shall find — that in like manner those great mountains of Asia were uplifted principally by the Indian Ocean. The plateau of Thibet in the Himalayas of Asia corresponds exactly with that of Titicaca in the Andes of South America; and as the latter was formed with the Andes, so also the plateau of Tibet was formed with the Himalayas... This seems absolutely clear and incontrovertible. And a similar mode of development must be ascribed to the table lands to the east and west of Tibet, so that the principal plateaus of Asia, Tibet and Iran, are clearly the work of the sea. The highest part of these plateaus is Tibet, with an average elevation of about 15,000 feet, and a width of about 500 miles at the highest part. At the middle it is somewhat wider, and to the west it narrows into Little Tibet, less than half the width of Tibet proper. It is evident that great Tibet was uplifted chiefly by movements from the direction of the bay of Bengal; this is shown by the lay of — 1908] THE PHYSICS OF THE EARTH. 209 the mountain chains south of Tibet, and by the great earthquake belt still persisting in the valleys of the Ganges and Brahmaputra. In the case of North America the plateaus are broader and cor- respondingly lower than those of South America and Asia. But if the sea gave rise to the uplifts connected with the Andes and Himalayas, can anyone doubt that the plateaus of North America are due to the same cause? The fotal volume of the North American Fic. 5. Relief Map of Asia. (From Frye’s Complete Geography, by permission of Ginn & Co., Publishers.) The mountains along the east coast illustrate the successive stages in the recession of the Pacific Ocean. At some future time the border of the continent will extend to the string of islands running from Kamchatka to the Philippines, the shallow seas of Japan and China becoming inland valleys. 210 SEE—FURTHER RESEARCHES ON cApeien Fic. 6. Relief Map of Africa. (From Frye’s Complete Geography, by permission of Ginn & Co., Publishers.) The reader should notice how the highest mountains along the east coast face the Indian Ocean, which is a continuation of the Pacific. 1908.] THE PHYSICS OF THE EARTH, 211 plateau is comparable with that in Asia, and it is easy to see how the relief of the Pacific on our side may have taken the form of a table-land of greater width but smaller height. The numerous parallel mountain chains west of the Rocky Mountains show the nature of the mighty forces at work, and prove that this uplift was the work of the Pacific Ocean. § 27. The forces which have raised the mountains and plateaus of the globe are identical with those which have raised the conti- nents above the sea, and all these forces depend on the leakage of the oceans.—The geological evidence of the slow operation of the forces which have uplifted the plateaus and mountains shows the immeas- urable ages during which they have been at work. Sometimes large portions of a continent have risen for a time, and again slowly subsided, and thus have arisen the phenomena noted in the sedi- mentary rocks studied in geology. These gentle movements often are without violent earthquake shocks, because the yielding is very gradual, and the crust is slowly raised up and down without breaking. It is only where the expulsion of lava from under the sea is rapid and violent that breaking develops at such rate as to form mountain chains and plateaus. The uplift of a plateau also requires a large amount of material. Where the process is gentle and gradual a whole continent may be slowly uplifted, and this process evidently has raised the low broad plains above the water. The cause of epeirogenic and of orogenic movements is everywhere one and the same. The movements take different forms according to the sud- denness with which the forces act; but both depend on the leakage of the oceans, and not at all on the secular cooling of the globe, the effect of which is insensible.* 1 Since this was finished the writer has carefully recalculated the shrink- age of the earth’s radius in 2,000 years, and finds that it can not exceed 1.5 inches. This takes no account of the increase of the interior heat of our globe due to radio-activity. If this latter effect were taken into account probably there would be no shrinkage whatever. Quite independently of these effects, however, there is an actual expansion of the globe due to the leakage of the oceans. In the same way it is found, by the application of Fourier’s theory of heat to the cooling at the surface, that the total shrinkage in the length of a continent such as North or South America, assumed to be equal to the terrestrial radius in length, is less than 1.5 inches. This again takes no 212 SEE—FURTHER RESEARCHES ON LApeil a Such an inference seems justified by the study of the mountains and plateaus of the world, and also by the movement of the strand line which Professor Suess has so carefully traced in every country. Almost everywhere the level of the sea has been lowered in recent geological time. During his travels in South America, Darwin recorded many observations to show that Patagonia and the whole end of the continent south of the La Plata had been recently elevated above the sea; and he mentions a channel in the Andes quite a distance north of the Straits of Magellan which gave evidence of the former passage of the sea through it. In view of these well-established facts, can any one doubt that the Straits of Magellan will eventually become dry and Tierra del Fuego be added to Patagonia? This whole region shows vast walls of rock towering vertically thousands of feet above the sea; evidently they were uplifted by earthquake forces from beneath, sometimes working quietly, and again spas- modically. As surely as Calabria in Italy has been uplifted from the Mediterranean, by that sea, just so surely has the southern end of South America been raised up by the southern ocean. And if an end of a continent can be upraised, obviously whole continents can be uplifted. Accordingly in the leakage of the oceans and the relief taking place under the land which bounds them we have the true cause of continent-making. Some original inequalities of surface may have existed after the detachment of the moon from the consolidating globe, but these have since been enormously increased by the effects resulting from the leakage of the oceans. As the earth gets older, the lithosphere becomes more diversified, and the face of the earth more and more wrinkled. The situation of the great plateaus of the world facing the largest oceans gives a clear indication of the nature of the forces at work account of radium, the effect of which would be to diminish this calculated shrinkage, or do away with it entirely. By such comparisons as these, placed along side of the large horizontal and vertical movements noticed in earthquakes near the sea, which sometimes amount to from 30 to 50 feet at a single disturbance, we see the utter untenability of the old theories heretofore current in works on geology and the related sciences. Note added July 28, 1908. 1908. | THE PHYSICS OF THE EARTH. 2138 Fic. 7. Relief Map of Australia. (From Frye’s Complete Geography, by permission of Ginn & Co., Publishers.) The reader should notice how the largest mountains along the east coast face the Pacific Ocean. 214 SEE—FURTHER RESEARCHES ON [April 24, Fic. 8. Relief Map of Europe. (From Frye’s Complete Geography, by permission of Ginn and Co., Publishers.) The reader should notice how the principal mountain chains face the Mediterranean and the Atlantic. There is a trough in the sea bottom off the Scandinavian coast to which Professor Schiaparelli has called attention. 1908. ] THE PHYSICS OF THE EARTH. 215 by which these mighty uplifts have been produced. The complex folding of the mountains to the east of Tibet shows that the Pacific aided the Indian Ocean in producing this great uplift, but we cannot yet determine the relative importance of the parts played by the two oceans. § 28. On the Origin of the Alps and on the Extreme Crumpling and Folding which They Exhibit—The remarkable crumpling and folding noticed in the Alps has long been a matter of surprise and wonder to the naturalist. This phenomenon has always presented great difficulty to those who have attempted to explain the origin of the Alps. In the paper on the “ Cause of Earthquakes” (§§ 14, 16, 18, 23) we have outlined the theory of how the Alps were formed by the sea, and criticised the old theories as totally inade- quate to account for the observed crumpling. We propose here to develop the new theory a little further, and to show how it accounts for all the facts observed in a range such as the Swiss Alps, which are generally recognized as about the most complex system of moun- tains known upon the globe. If the new theory will explain the Swiss Alps, it will obviously explain any other mountain system in the world. The test of the theory as applied to the Alps may there- fore be regarded as an experimentum crucis. Fis. 9. Complex Folding. Section Across the Alps from the Neighborhood of Ziirich toward Como; about 110 miles. (Heim and Prestwich.) “ Windgille eeewees nee Fic. 10. Section through the Alps, Showing the Effects of Complex Folding. (From Heim’s Gebirgsbildung.) The line of the St. Gotthard Tunnel and the plane of equal temperature, AB, beneath it, are compiled from F. Giordano, in Bolletino del R. Comitato Geologico d’Italia, Vol. XI., 1880, pp. 408-50. 216 SEE—FURTHER RESEARCHES ON [April 24, The accompanying figures exhibit: (1) A general section of the Alps from Ziirich to Lake Como (Heim and Prestwich), and (2) a section on a larger scale of a portion of the central Alps (from Heim’s Gebirgsbildung) with fan-shaped folds and imversion of strata on the two sides. It can hardly be assumed that these illus- trations are extremely accurate, but no doubt they are free from large errors in exhibiting the general character of the folding, which gives here and there fan-shaped structures with overturned dips at the sides. Now the explanation of such structures is the most difficult prob- lem heretofore presented to the geologist. They exhibit conspicuous lateral and vertical movements which cannot well be accounted for by the contraction theory. A shortening of about 74 miles (Heim) in the folding, which has amounted to 50 per cent. of the whole span of crust (Leconte), can not be accounted for, on the old theory, without assuming that the crust is loose from the globe, so that a vast amount of slack could be brought forward and concentrated in the folds at one point, in the Swiss Alps. This is clearly unthinkable. On the other hand, the cone of matter underlying the Alps with vertex at the center of the earth could not be sufficiently condensed to give the required slack in the overlying crust without increas- ing the density of the cone by 50 per cent., which could easily be detected by geodetic observations, owing to the resulting deviations of the plumb line. Accordingly we may feel sure that the matter under the Alps not only is not denser than the average, but actually lighter, by an appreciable amount. The crumpling of the Alps cannot therefore be due to condensation beneath these mountains. How then did the folding arise? If we cut a section across the Aleutian Islands perpentiioHial to the chain and the parallel trench lying to the south, we shall have a figure something like that shown in figure 1 of the following plate. Now in the paper on the “ Cause of Earthquakes ” (§ 16) we have shown how the undermining of the sea bottom sinks the trough down | deeper and deeper, and as the expulsion of lava continues it eventu- ally becomes easier to fold up the side of the trough towards the ocean (at b) and make another range of mountains parallel to the first. And there is nothing to prevent the process from being re- 1908, ] THE PHYSICS OF THE EARTH. 217 peated several times. When several successive ranges of mountains are thus developed in the process of expulsion under the margin of the sea, it is easy to see that the central range may finally be driven upward and flared out at the top exactly as in the Alps. Thus all this movement occurs in the sea, and eventually the range becomes like that now seen in Switzerland, as depicted by Heim, of Ziirich. t 2e@ level_ __ _ ---p Rage ok Tua 1. Mountain Range rising in the Sea. 2 ae 6. Whole Mountain Range rising from the sea. a D Seetiper 2S ep Rap. Level __.. LAising from *he sea continued, giving fan-shaped structures and overturned alps. Fic. 11. Illustration of Formation of Complex Range, such as the Swiss Alps. The bending of the crust. has caused it to pull apart at the top and bottom of the folds, where it is largely covered by sedimentary deposits and filled by molten rock from beneath, so that the breaks do not show at the surface, unless erosion has laid bare parts of the underlying structure. In these figures the thickness of the crust is less than half the width of the folds; and for clearness the depth of the sea is exaggerated. 218 SEE—FURTHER RESEARCHES ON [April 24, As. the movement continues the central range rises upwards, while its flanks sink down on either side, and thus the fan-shaped structure develops, so as to give overturned dip and inversion of strata once deposited horizontally in the bed of the sea. This is a perfectly simple and direct explanation of one of the most mysterious phenomena heretofore encountered by naturalists. The new theory of mountain formation is proved to represent a real law of nature by phenomena now witnessed in the Aleutian Islands, Japan and elsewhere. The fact that it perfectly accounts for the perplexing phenomena seen in the Swiss Alps, shows that they too were formerly under the sea, and were uplifted by the same. force now at work in the Aleutian Islands and the Antandes. Accordingly it is not remarkable that Professor Suess should, without knowledge of the trwe cause, describe the uplift of the Alps from the sea in words which are almost prophetic (“Face of the Earth,” Vol. II, p. 552): “As a result of tangential thrusts, the sediments of this Sea (Mediter- ranean) were folded together and driven upward as a great mountain range, and the Alps have therefore been described as a compressed sea.” Without overestimating the significance of this result, it seems clear that neither parallel ranges nor fan-shaped structures with inverted dips will hereafter present any further difficulty to the geologist. Now that the true laws of such phenomena are known, it will be exceedingly interesting to work out the details of all the great mountain systems with which the earth is adorned. § 29. All Complex Folding now seen in Mountain Ranges Originated in the Sea.—It is scarcely necessary to add that all the complex folds now seen in mountain ranges were produced in the sea by the repetition of trenches dug out by earthquakes. The folds were frequently broken apart at both top and bottom, by the earthquake movements, and thus the folded crust is not shortened by anything like so much as has been supposed. Moreover where the fan-shaped structures and overturned dips appear, the two sides were never joined together by an arch above, as represented in the above figures by Heim, but were quite separated before the range arose to any considerable height. Accordingly it follows that erosion has not worn off anything like so much of the top of the range as 1908. | THE PHYSICS OF THE EARTH. 219 the theory of a rounded arch would require. Thus we may not only explain the folds of the Alps, but also recognize that the folds both above and below were less extensive than was formerly sup- posed; and this greatly simplifies the labor of the geologist in re- storing the former structure of mountain chains as they appeared before they were greatly eroded. Ps is pes Section of North America, Fast to West (Dana). ae au Section of South America, Fast to West (band). on a ea Section of Asia, North to South (Oana). eT Section of Africa, North to South (Dana). — aie tly Section of Africa Last to West (Lane). _ Tibetan Jebletand TE TE TO EO TE Ea PE Se Alps eR; Fic. 12. Sections of the Continents, and of the Alps and Himalaya on the same Scale. (Gen. Strachey.) Himalayas The process of undermining the sea bottom in the expulsion of lava arising from the leakage of the ocean, has given rise to all the important folds of the earth’s crust. Thus arose all the complicated folds in the Alps, Andes, Alleghenies and other mountain ranges. And wherever we see these folds sea trenches once existed, and the ‘220 SEE—FURTHER RESEARCHES ON [April 24, crust was pushed hither and thither by earthquakes, raising ridges and undermining the troughs, till the rocks were crumpled and folded as we find them to-day. The simplicity of this cause, and the easy way in which we pass from the living troughs now being dug out in the sea to fossil troughs long since dead and now far inland give a genuine paleontological interest to the science of mountain formation. What has long been mysterious and nearly inexplicable is now as clear as any theorem in geometry. § 30. Application of the New Theory to the Allegheny Moun- tains—The Allegheny Mountains in Pennsylvania and Virginia are very remarkable for the great extent of the folds, and it seems worth while to dwell a moment on the mode by which these folds were produced. We have seen that they all arose in the sea, and by a repetition of the earthquake process of digging out trenches along : the ancient shore line. As we shall see in Part V, § 41 of this paper, Professor James Hall so long ago as 1857 announced to the Ameri- can Association in session in Montreal that the enormous thickness of the formations along the Appalachian Chain in the United States was due to the prolonged accumulation of sediments over a sinking sea bottom, at the margin of the continent; where the marine cur- rents allowed the material to deposit. Obviously if sea trenches were dug out by earthquakes they would become the basins for the accumulation of a vast amount of detritus. And when several trenches were successively dug out in the sea bottom by earthquakes depending on the Atlantic, would not the resulting folds give us the Allegheny, Tuscarora and Blue Ridge Mountains of Pennsylvania and Virginia? The famous Shenandoah Valley in Virginia is nothing but an ancient sea trough; and Penn- sylvania has many such valleys originally formed in the depths of the sea. This is clearly indicated by the beautiful parallelism of the mountain ranges. It is noticeable that the sea trench south of the Aleutian Islands is remarkably straight, and one may easily predict that the ranges hereafter to be formed in the North Pacific Ocean will be remark- ably parallel like those now seen in Virginia and Pennsylvania. Under the circumstances can any one doubt that the sea was once very deep near where the Blue Ridge stands to-day? 1908, | THE PHYSICS OF THE EARTH. 221 Excluding from consideration the crystalline belt ‘on the east, Claypole estimated the shortening of the Appalachians in Pennsyl- vania at 46 miles. In the same way McConnell estimated that of the Laramide range in British America at 25 miles, and Leconte that of the Coast Range in California at from 9 to 12 miles. Cor- responding estimates have been made for many other mountain ranges; but, for reasons already given in dealing with the origin of the Swiss Alps, § 28, these estimates are too large. The crust was broken apart at both top and bottom when the ranges were in the sea, and the folds heretofore assumed to be complete were never really so. Consequently no slack in the earth’s crust is re- quired to explain these folds; it was never loose from the globe and never moved horizontally, except when forced by earthquake move- ments proceeding from the underlying trenches in the sea bottom. The undermining and folding of the crust has given the Ap- palachian Mountains in many places the aspect of a series of immense billows, running parallel, as if swept in by a vast disturbance of the sea. But not even seismic sea waves of the most imposing magnitude could approach the size of these gigantic folds, the origin of which heretofore has been so mysterious. The finding of a simple and natural explanation of these great billows of the land will be scarcely less interesting than the discovery of the cause of seismic sea waves. Both depend on earthquakes, though in very different ways. The land billows are cumulative products of an infinite series of seismic disturbances along the margin of the sea; the seismic waves are small in comparison, and result from a single disturbance of the sea bottom, made in process of shaping the vast billows of the land, which in all generations have appealed to the imagination of the painter, poet, and student of nature. § 31. Analogy Between the Uplift of the Islands of Japan by the Movement from the Tuscarora Deep and of the Plateau of Tibet from the Indian Ocean.—The uplift of the Islands of Japan now going on by the expulsions of lava from beneath the Tuscarora Deep is proved by the terrible earthquakes and seismic sea waves afflict- ing that region, as well as by the historical fact that the east coast of Japan is known to be rising from the sea. Perhaps in general the movement is slow and insensible, but occasionally earthquakes PROC, AMER. PHIL, SOC. XLVII. 189 O, PRINTED SEPTEMBER 23, 1908 \ 222 SEE—FURTHER RESEARCHES ON [April 24, have produced large disturbances of the level. The nature of earth- quake movement in expelling lava from under the sea is too well known to leave any doubt as to what is going on in Japan. And the theory is confirmed by the fact that if Nipon and Yezo were dug off and thrown into the Tuscarora Deep they would about fill up that profound abyss and leave the sea of average depth. Now there is a certain analogy between the uplift of these Japanese Islands, which are considerable areas, by the Pacific, and of the Plateau of Tibet by the Indian and Pacific oceans com- bined. Undoubtedly the valleys of the Indus, Ganges and Brahma- putra are the relics of ancient sea troughs which largely produced the Himalayas and the great plateau of Tibet. How much these troughs have been modified in later geological times we cannot estimate; but even now enough remains to tell the true story ot Himalayan development. This is also indicated by the preservation of the earthquake belt south of the Himalayas. The meaning of these valleys and earthquake belts admits of no possible doubt. Just as the whole island of Nipon is being raised by movements from the Tuscarora Deep, so the whole of the Plateau of Tibet was once raised by an Indian Deep, of which these valleys are the remains. In the same way the Valley of the Po is the remains of the sea valley which was most influential in uplifting the Swiss Alps. But in the case of the Alps, Geikie has shown that there was also a sea on the north, which has now quite disappeared, though traces of its former existence still remain. § 32. The Origin of Volcanoes and the Conditions of their Maxi- mum Development.—It appears from the line of proof developed in this theory that volcanoes may break. forth in any region near the sea where there are severe earthquake disturbances, by which the crust of the globe is sufficiently cracked to afford a vent for the steam imprisoned beneath. Now such vents are greatly facilitated in a chain such as the Aleutian Islands, in which the crumpling is extreme, and the expulsion of lava from beneath the sea rapid and violent. The crumpling breaks the crust along many lines, and as the earthquakes due to the expulsion of lava are both frequent and terrible, the chance of steam breaking through to the surface 1908. ] THE PHYSICS OF THE EARTH. 223 is much greater than in regions less wrinkled and less afflicted by earthquakes. The crust in the Andes was once folded by the sea in the same way as that in the Aleutian islands, and from this circumstance arises the violence of the volcanic outbreaks noticed all along the west coast of South America. From the great simi- larity of the volcanic phenomena in the Andes and in the Aleutian Islands, and its enormous prominence in both ranges, it seems obvious that we have here the conditions for its maximum devel- opment. Charles Darwin believed that volcanoes usually break out in regions of elevation. No doubt this is true, for mountain ranges are the most conspicuous of rising areas. And according to this theory the tendency to rupture the crust is a maximum, when the ranges are being both folded and raised from the sea. Thus while some volcanoes may break out in less fractured regions of the earth’s crust, the greatest volcanic activity develops where mountains are being formed in the sea, as in the Aleutian Islands. This view also enables us to understand why many volcanoes in the Andes are now extinct, though they were formerly active for immense periods of time, as we know from the thick deposits of volcanic debris and the immense height of the cones built up of lava, ashes and cinders. IV. CoMPARISON OF THE NEw PuHysicAL THEORY OF MOUNTAIN FoRMATION DEPENDING ON THE LEAKAGE OF THE OCEANS WITH THE THEORY OF SECULAR COOLING AND CoNn- TRACTION HERETOFORE HELD By MEN oF SCIENCE. § 33. General Remarks on the Method of Comparison Adopted.— The new physical theory of mountain formation depending on the leakage of the oceans outlined in the three memoirs recently published by the American Philosophical Society and somewhat more fully developed in the present paper might seem incomplete if we failed to compare the new theory with the theory of secular cooling and contraction of the globe heretofore held by men of science generally. On several grounds an examination of the older theory can hardly fail to be instructive. And if this comparison of the older theory with that now adopted shall be the means of har- 224 SEE—FURTHER RESEARCHES ON [April 24, monizing in any considerable degree the divergent views heretofore prevailing, and of showing that there is no important geologicat phenomenon which the new theory does not explain in a more simpie and direct manner than the old theory, such a comparison will no doubt: seem quite justifiable. For it is highly desirable to establish the adequacy of the new theory to explain the geological as well as. the physical phenomena noticed at the surface of the earth. In making this comparison it is necessary to bear in mind that the geological data on many points are still very incomplete, and therefore we should expect agreement with the body of phenomena rather than with the details, about which much uncertainty still exists. Owing to the incompleteness of our knowledge of the mode of origin of the great mountain chains of the globe, the best plan of procedure seems to be: First, to give an exposition of the views of previous writers in regard to the individual great mountain sys- tems; second, to add a résumé of the views of certain great geolo- gists on mountain formation in general. Obviously such conden- sation of the views of others should wherever possible be given in their own words. As this subject is extensive and widely scattered in a variety of publications, we must content ourselves with selecting those citations which seem of most interest, without in any way claiming to exhaust the subject. Indeed it may well be that some discussions of value will be entirely overlooked, but, as the theories have been but very little changed for many years, it is hoped that the following citations will be found adequate to give an intelligent grasp of the views heretofore accepted by the leading authorities. If there be those who doubt the propriety of including lengthy quotations from well-known authors, I must plead in extension of the course here adopted, that this memoir is intended for others besides geolo- gists, and that all who are interested in the physics of the earth, whether they be mathematicians, astronomers, physicists, seismolo- gists, geologists, or even chemists and biologists, are entitled to have a clear summary of the principal theories heretofore accepted in re- gard to the development of our globe. In dealing with a subject of such universal interest to all men of science, any reasonable conden- sation of the previous theories may be considered admissible, and one mt, THE PHYSICS OF THE EARTH. 225 may have no hesitation in invoking the aid of many authors. If the establishment of a great law of nature may be thus facilitated, surely no one will doubt that the space utilized was devoted to a most useful purpose. The extreme specialization characteristic of the science of our day makes such summaries both useful and necessary for the intelligent study of great problems; and if more effort were made in this direction it might contribute materially to the progress of scientific research. (A) Accounts oF PARTICULAR MouUNTAIN SYSTEMS, AND THEIR SupposED Mope or DEVELOPMENT. § 34. The Andes.—We shall begin with the Andes of South America, because this is one of the largest, simplest and most typical of mountain systems; and if a theory will not explain the Cordilleras, we may despair of its explaining the more compli- cated mountains of the globe. The’ reader should carefully bear in mind not only what the author in question says from his own point of view, but also how the facts he mentions accord with the new theory developed in this paper. In the Encyclopedia Britannica, ninth edition, under the article “Andes,” we find the following lucid exposition of Andean de- velopment. It is not signed, but is supposed to have passed under the review of Sir Archibald Geikie. “The formation of the Andes is due to several causes operating at dis- tinct intervals of time. They consist mainly of stratified material which has been more or less altered. This material was deposited at the bottom of a sea, so that at some former time the highest portions were submerged, probably in consequence to a certain extent, of subsidence of the sea bottom. Since the latest deposits there has been upheaval and denudation. The range, then, has resulted from the accumulation of sediment on a subsiding area; from the subsequent upheaval of such deposits, which haye been increased in height by the ejection of volcanic products; and from the operation of denuding agents. “As far as our present knowledge goes, it appears to be probable that the Andes mark an area on which sedimentary deposits have been accumulated to a greater thickness than on any other portion of South America. It is further demonstrable that these deposits belong to several geological periods, the elevation having occurred at different periods, while their axes extend in different directions. Hence it is a complex range of mountains formed by the combination of several distinct systems of ridges. The width of the 226 SEE—FURTHER RESEARCHES ON [April 24, range varies from about 60 to 300 or more miles, but, as compared with other mountains, the Andes are for the most part narrow relatively to their height. Where their special features are most characteristically developed, they consist of a massive embankment-like foundation, rising with a rapid slope from the low country on either side, and having its margins sur- mounted by lofty ridges of ragged or dome-like summits. These Cor- dilleras, as they aré usually termed, flank longitudinal valleys, or plain- like depressions which form the highest levels of the central portion of the gigantic embankment, and which vary in width from twenty to sixty miles. At intervals the longitudinal depression is broken up, either by ridges connecting the Cordilleras, or by lofty plateau-like uplands. In several cases these transverse ridges and belts of high ground form the main watershed of the country. They are rarely cut across by the river systems, whereas both the marginal Cordilleras are intersected at numerous points, and more especially by the rivers draining the eastern slope of the country. In no case do these eastern rivers originate to the west of the western Cordilleras. A few of the central valleys, or plain-like depressions, have no connection either with the western or eastern river system. Roughly speaking the height of the central plains or valleys is from 6000 to 11,000 feet above the sea; of the passes and knots, from 10,000 to 15,000 feet; and of the highest peaks, from 18,000 to 23,290 feet—the last being the altitude of Aconcagua in Chili, which is generally considered to be the highest peak in America. Judging from these estimates, we may regard the bulk of the Andes as somewhere about that of a mass 4400 miles long, 100 miles wide, and 13,000 feet high, which is equivalent to 5,349,801,600,- 000,000 cubic feet. On this basis we find that the Mississippi would carry down an equivalent mass of matter in 785,000 years. The rate of denuda- tion in certain river basins varies from one foot in 700 years to one foot in 12,000 years. Assuming that similar rates would apply to the Andes, they would be denuded away in from 9 to 156 million years. In all proba- bility, much less than 9 million would suffice. On the other hand the Andes would be swept away in 135,000 years, supposing the denuding powers of the globe were concentrated on them alone. From the above data, and assuming the average specific gravity of the matter forming the Andes to be 2.5, the weight of the portion above the sea may be estimated at 368,- 051,834,482,750 tons, giving an average of about 1,000 tons on each square foot at the level of the sea. Under Aconcagua the pressure would be about 1,780 tons per foot at the same level, provided, of course, it were not, as it no doubt is, more or less modified by lateral pressure. These figures afford some, though at best a vague, conception of the mighty grandeur of this range of mountains, and of the scope there is for the exertion of enormous pressure. How vast then, must be those forces which have counteracted such pressures, and upheaved the ocean-spread sediments of the continents, until the Andes, that ‘giant of the Western Star, Looks from his throne of clouds O’er half the world!’ 1908.] THE PHYSICS OF THE EARTH. 227 But, however vast the Andes may seem to us, it should be remembered that they form but an insignificant portion of the globe itself. Aconcagua is about 1/2,000 of the earth’s diameter, which is relatively not more than a pimple 1/30 of an inch high on the skin of a tall man.” (Ency. Brit., Vol. II, pp. 15-16.) The account here given of how the Andes were formed seems exceedingly instructive. In the sea troughs formerly existing be- tween the ocean and the eastern range, which was the first thrown up, we have a complete explanation of the extraordinary depth of sedimentation; for in such trenches adjacent to a new range the rate of sedimentation would be a maximum. The subsequent up- lifting of the western side of the sea troughs, with the vast lateral folding and compression necessarily accompanying this movement, accounts for the plateaus, valleys and general structure of the Andes, as well as for the violent volcanic outbreaks, which are said to greatly predominate in the range nearest the sea, from which the expulsion of lava giving rise to this mighty Cordillera pro- ceeded. The vastness and height of the Andes and the terrific forces operating to erect this gigantic wall along the shore of the continent is a true measure of the secular leakage of the Pacific Ocean, and of the automatic relief it finds by folding the earth’s crust along the border, in the countless successive expulsions of lava from beneath the bed of the sea. It is needless to point out how perfectly the new theory explains the persistence of the earthquake belt along the western shore of South America, and of the seismic sea waves by which that region is so often afflicted. It is obvious that the forces which uplifted the mountain also car- ried up the plateaus enclosed between the various ranges. § 35. The Himalayas.—The following luminous account of the Himalayas by the late Lieutenant General Sir Richard Strachey, Encyclopedia Britannica, article “ Himalayas,” is of extreme in- terest. General Strachey resided in India for many years, and made a life long study of the Geology and Geography of Central Asia. He was the principal authority of his time on this little explored continent and died February 12, 1908, at the age of QI years. “Scientific investigation has clearly shown that, so far as the main characteristics of the mountains are concerned, the natural boundaries of the Himalayan system must be carried much farther than had at first been 228 SEE—FURTHER RESEARCHES ON [April 24, recognized. Considerable obscurity still involves the eastern portion of these mountains, and there is great want of precise knowledge as to their connection with the ranges of western China, from which are thrown off the great rivers of China, Siam, and Burmah. On the west, however, it has been completely established that a continuous chain extends beyond the Indus along the north of the Oxus, and ends in that quarter about 68° E. long. In like manner it is found that no separation can be established, except a purely arbitrary one, between the Himalaya as commonly defined and the greatly elevated and rugged table-land of Tibet; nor between this last and the mountain ranges which form its northern border along the low-lying desert regions of central Asia. “It thus appears that the Himalaya, with its prolongation west of the Indus, constitutes in reality the broad mountainous slope which descends from the southern border of the great Tibetan table-land to the lower levels of Hindustan and the plains of the Caspian; and that a somewhat similar mountain face, descending from the northern edge of the tableland, leads to another great plain on the north, extending far to the eastward, to the northern borders of China. Towards its northwest extremity this great system is connected with other mountains—on the south, with those of Afghanistan, of which the Hindu-Kush is the crest, occupying a breadth of about 250 miles between Peshawur and Kunduz; and on the north, with the mountains that flank the Jaxartes or Sir on’ the north, and the Thian- shan or Celestial Mountains. The eastern margin of Tibet descends to western China, and the south-eastern termination of the Himalaya is fused into the ranges which run north and south between the 95th and tooth meridians, and separate the rivers of Burmah, Siam, and western China. “Nor can any of the numerous mountain ranges which constitute this great elevated region be properly regarded as having special, definite, or separate existence apart from the general mass of which they are the com- ponent parts; and Tibet cannot be rightly described, as it has been, as lying in the interval between the two so-called chains of the Himalaya and the Kouenlun or Kara Koram. It is in truth the summit of a great pro- tuberance above the general level of the earth’s surface, of which these alleged chains are nothing more than the south and north borders, while the other ranges which traverse it are but corrugations of the mass more or less strongly marked and locally developed. “The average level of the Tibetan tableland may be taken at about 15,000 feet above the sea. The loftiest points known on the earth’s sur- face are to be found along its southern or Himalayan boundary; one of them falls very little short of 30,000 feet in elevation, and peaks of 20,000 feet bound the entire chain. The plains of India which skirt the Himalayan face of the tableland, for a length of rather more than 1,500 miles, along the northern border of British India, nowhere rise so much as 1,000 feet above the sea, the average being much less. The low lands on the north, about Kashgar and Yarkend, have an elevation of from 3,000 to 4,000 feet, and no part of the Central Asiatic desert seems to fall below 2,000 feet, the lake of Lob-nor being somewhat above the level. The greatest dimen- 1908.] THE PHYSICS OF THE EARTH. 229 sion of the Tibetan mountain area from east to west may be about 2,000 miles, while its average breadth somewhat exceeds 500 miles; about 100 miles on either side constitute the sloping faces, the central tableland having a width of about 200 miles on the west and probably, 500 miles at its eastern border.” General Strachey thus shows that the Himalayan mountains and Tibetan Plateaus are directly and intimately connected as merely different parts of one great continuous movement of the earth’s crust. After describing many features of the Himalayas, General Strachey continues: “The general conclusion that may be drawn from the facts of structure thus briefly indicated is that the elevation of the Himalaya to its present great height is of comparatively recent occurrence. An area of land must have existed where the main line of snowy peaks now stands, which has not been submerged since the Paleozoic period, and which ‘then had its northern boundary somewhere along what has been termed the Indian water- shed. Evidence of a similar ancient sea on the south also exists, but in less definite shape; and whether it was united with the northern sea or not is still a matter of conjecture, though the distinctive character of the fossils rather indicates that there was no direct union. The possible connection of this ancient Himalayan land. area with the pre-Tertiary land of the peninsula of India is also only a matter for speculation. “There is further reason to infer that the existence of the great line of peaks is rather due to some previous line of elevation on the ancient land, which has continued to retain its relative superiority while the whole areas have been raised, rather than to any special line of energy of upheaval of recent date; and that the fundamental features of its former configura- tion of surface in mountain and valley have been preserved throughout. There is evidence for the conclusion that the chief rivers of the pre- Tertiary land issued from the mountains where the present main streams are found, and this embryo Himalaya may have been of such moderate height as to have permitted the passage across it of the Siwalik mammals, the re- mains of which appear both on the border of the Indian plain and in Tibet. It is after the middle Tertiary epoch that the principal elevation of these mountains must have taken place, and about the same time also took place the movements which raised the tablelands of Afghanistan and Persia, and gave southern Asia its existing outlines. . “The best answer that can be given to an inquiry as to how changes of level could have arisen, such as those which are observed in the Hima- laya, is that they should be regarded as due rather to secondary actions consequent on the general contraction of the cooling terrestrial sphere than to direct elevating forces, for which no known origin can be assigned. The contraction of the cooling but now solid crust of the earth must have set up great horizontal strains, partly of tension and partly of compression 230 SEE—FURTHER RESEARCHES ON [April 24, which would necessarily have been followed by rupture or crushing along lines of least resistance, and the movements on such lines are marked by the great mountain ranges that traverse the surface. A dislocation of the solid crust of the earth once having taken place, it would probably continue to be a line of least resistance ever after, and a succession of movements during past geological periods may thus be reasonably expected along such lines. Somewhat in proportion as the disturbing forces are intense, and the thickness of the crust on which they act is great, will be the tendency of the lines of rupture to be continuous for a considerable distance; and as the disturbed area is extended in its dimensions, the probability will increase of a repetition of a series of similar dislocations on lines approxi- mately parallel to, or at right angles to, one another and to the line on which the greatest compression and consequent tension take place. In a disturbed area, one transverse dimension of which is sensibly greater than the rest, the longitudinal ruptures will predominate in the interior and the transverse towards the borders. Almost all mountains give indications of having been shaped by forces thus related, and to the action of such forces may the main characteristics of the structure of the Himalaya, and the arrangement of its ridges and valleys be attributed. Whatever may be the power of rivers in general as instruments of erosion, and whatever effect the Himalayan rivers have had in removing the fragments of the rocks over and among which they took their courses, it is hardly possible to doubt that their main directions were determined by the anterior lines of dis- location which opened up hollows down which they could flow, and which must invariably have been accompanied by a destructive and crushing action on the rocks along them, which has enabled the waters the more readily to sweep away the obstacles in their path. The parallelism of many of the great Tibetan and Himalayan rivers for hundreds of miles together, and such mountains, seems wholly inexplicable in any other manner.” (Ency. Brit., p. 828.) This account is quite clear and satisfactory, except that part of it which deals with the cooling and contraction of the globe. Here General Strachey has made the best of a very inadequate hypothesis. Just as the Andes were formed by expulsions of lava from under the Pacific, so also here the Himalayas were formed by a corre- sponding movement due mainly to the Indian Ocean, which has also raised high mountains along the eastern border of Africa. We can- not yet give all the details of the Himalayan development, but in general it is evident that it was similar to that of the Andes. The uplift of the great plateau of Tibet corresponds to that of Titicaca. And the parallel ranges of the Himalayas originated by the usual process of the folding up of successive sea trenches. On the 1908.] THE PHYSICS OF THE EARTH. 231 outside of these mountains there still remain trough-like depressions where the Indus, Ganges and Brahmaputra now flow. The under- mining produced in raising the Himalayan embankment still shows in the valleys to the south, though the sea has receded; and the great earthquake belt south of the Himalayas still discloses to us the - nature of the forces which produced this mighty uplift. The following critical passages by General Strachey are also of decided interest: “The great peaks are, with few exceptions, composed of schistose rock, though granite veins may be seen in the mountain faces to very great ele- vations; one of these exceptions is the great peak of Kamet in Kumaon, which rises to about 25,000 feet in what appears to be a mass of grey granite. “Passing to the north of the line of great peaks the metamorphosed schists are suddenly replaced by slates and limestones, which are in many places highly fossiliferous, exhibiting what appears to constitute in the aggregate a fairly continuous series from the Lower Silurian to the Cre- taceous formations, though the complete sequence has not been observed in any one locality. The western region of the Himalaya alone has been suf- ficiently explored to admit of any positive statements, but the indications gathered from such imperfect accounts and other data as exist relative to the eastern parts of the mountains leave little doubt that the change ob- served in the west on approaching and entering Tibet holds good on the east also, and that the general physical features of the whole tract are much alike, though doubtless with many differences in detail. “The fossiliferous strata of western Tibet are continued, though per- haps with some breaks, to the Tertiary period. In certain localities num- mulitic rocks, probably Eocene, have been observed, and from the great alluvial deposit which forms the plain of Gugé, already noticed, the remains of mammals, apparently of Siwalik age, have also been obtained. Among these were bones of the elephant and rhinoceros, the existence of which, in the present condition of these regions, would be wholly impossible; so that there is no room to doubt that these deposits have been raised from a com- paratively low level to their existing great elevation of upwards of 15,000 feet, since they were laid out. As in the case of the plain of India, we here, too, have no complete proof of the origin of these great nearly hori- zontal deposits, but it seems clear, from the materials of which they are formed, that they must have been laid out by the water, either by the sea or some great inland lake. They are largely composed of boulder deposits, and large boulders are strewed over the surface imbedded in the ground in a manner that seems only explicable as the result of the action of a con- siderable body of water. “ Several lines of granitic and eruptive rock occur in western Tibet, of which all that need here be said is that they appear all to be older than the Tertiary alluvium, but some of them are possibly contemporaneous with the nummulitic and older formations.” (Ency. Brit. p. 828.) 232 SEE—FURTHER RESEARCHES ON [April 24, In an earlier passage, after comparing some of the smaller Himalayan ranges to the Swiss Alps, General Strachey adds: “To obliterate these two ranges from the Himalaya would make no very sensible inroad on it, though they surpass in bulk the whole of the Swiss Alps; and it is no exaggeration to say that, along the entire range of the Himalaya, valleys are to be found among the higher mountains into which the whole Alps might be cast without producing any result that would be discernible at a distance of ten or fifteen miles. And it is important to bear in mind these relations of magnitude, for the terms at our disposal in the description of the mountains are so limited that it is necessary to employ the words chain, range, ridge, spur, etc, rather with reference to relative than to absolute importance, so that the scale of our nomenclature changes with the extent and altitude of the mountains of which we speak.” (Ency. Brit., p. 827.) § 36. The Alps.—tIn the Enclycopedia Britannica, article “ Alps,” by John Ball, we find the following brief outline of the salient features: “ Accurate knowledge of the Alps is so recent that few attempts have been made to establish a general division of the entire region, and it can- not be said that any one arrangement has obtained such general recognition as not to be open to future modification; but there is a pretty general agreement as to the main features of that here proposed, to which a few general remarks must be premised. “Whatever may have been the original cause of the disturbances of the earth’s crust to which great mountain chains owe their existence, it is gen- erally, though not universally, true that the higher masses (formed of crys- talline rock and geologically more ancient) are found towards the central part, and that these are flanked by lower ranges, composed of more recent rocks, which surround the central groups very much as an outer line of entrenchment may be seen to surround a fort. In most cases it is not possible to descend continuously in a nearly direct line from the crest of a great mountain chain to the plains on either side, for there are usually intermediate valleys, running more or less parallel to the central range, which separate this from outer secondary ranges. These in turn, are often ac- companied by external ranges, intermediate between them and the plains, and related to them as they are to the central ranges. The type of arrange- ment here described is more or less traceable throughout the greater part of the Alps, but is most distinctly exhibited in the eastern portion lying between the Adige and the frontier of Hungary. We have a central range, composed mainly of crystaline rock; a northern range, formed of secondary rocks, separated from the first by the great valleys of the Inn, the Salza, and the Enns; a southern range, somewhat similar to the last in geological structure, divided from the central one by the Rienx, or east branch of the Adige, and the Drave. Flanking the whole, as an external entrenchment on the north side, are the outer ranges of the Bavarian Alps, of the Salzkam- 1908. ] THE PHYSICS OF THE EARTH. 233 mergut, and of Upper Austria, to which corresponds on the south side the Monti Lessini, near Verona, the mountains of Recoaro, those of the Sette Comuni, and the considerable masses crowned by the summits of the Grappa, the Col. Vicentino, the Monte Cavallo, the Monte Matajur, and Monte Nanos. Where, as in the case above mentioned, the secondary ranges of the Alps rise to a greater altitude, and are completely separated from the neighbouring portions of the central chain, it is impossible not to distinguish them as distinct groups; but the outermost ranges, which rarely rise above the forest zone, are in all cases regarded as appendages of the adjoining groups. These outer ranges are called in German Voralpen, and in Italian Prealpi.” (Ency. Brit., p. 623.) Again on page 620, this author remarks: “In every mountain system geographers are disposed to regard the watershed, or boundary dividing the waters flowing towards the opposite sides of the range, as marking the main chain; and this usage is often justified by the fact that the highest peaks lie on, or very near, the boundary so defined. In applying this term in the case of the Alps, there are, however, difficulties arising from their great extent and the number of their branches ‘and ramifications. Many of the loftiest groups lie altogether on one side of that which we call the main chain, and at the eastern extremity, where all drainage is ultimately borne to the Black Sea, we must be partly guided by geological considerations in deciding which of several ranges deserves to be considered pre-eminent.” (Vol. I., p. 620.) Sir Archibald Geikie’s discussion of the origin of the Alps, in the article “ Geology,” Encyclopedia Britannica (pp. 373-374), bears on the problem now before us: “The Alps, on the contrary, present an instructive example of the kind of scenery that arises where a mass of high ground has resulted from the intense corrugation and upheaval of a complicated series of stratified and crystalline rocks, subsequently for a vast period carved by rain, frost, springs and glaciers. We see how, on the outer flanks of those mountains among the ridges of the Jura, the strata begin to undulate in long wave-like ridges, and how, as we enter the main chain, the undulations assume a more gigantic tumultuous character, until, along the central heights, the mountains lift themselves towards the sky like the storm-swept crests of vast earth billows. The whole aspect of the ground suggests intense commotion. Where the strata appear along the cliffs or slopes they may often be seen twisted and crumpled on the most gigantic scale. Out of this complicated mass of material the sub-aerial forces have been ceaselessly at work since its first elevation. They have cut valleys, sometimes along the original depressions, sometimes down the slopes. They have eroded lake-basins, dug out corries or cirques, notched and furrowed the ridges, splintered the crests, and have left no part of the original surface unmodified. But they have not effaced all traces of the convulsions by which the Alps were upheaved.” 234 SEE—FURTHER RESEARCHES ON [April 24, In his account of the Miocene (“ Text-book of Gralonys p. 1261, edition of 1903), Geikie says: “The Gulf of Gascony then swept inland over the wide plains of the Garonne, perhaps even connecting the Atlantic with the Mediterranean by a strait running along the northern flank of the Pyrenees. The sea washed the northern base of the now uplifted Alps, sending, as in Oligocene time, a long arm into the valley of the Rhine as far as the site of Mainz, which then properly stood at the upper end, the valley draining southward instead of northward. The gradual conversion of salt into brackish and fresh water at the head of this inlet took place in Miocene time. From the Miocene firth to the Rhine, a sea-strait ran eastwards, between the base of the Alps and the line of the Danube, filling up the broad basin of Vienna, sending thence an arm northwards through Moravia, and spreading far and wide among the islands of southeastern Europe, over the regions where now the Black Sea and Caspian basins remain as the last relics of this Tertiary extension of the ocean across southern Europe. The Mediterranean also still presented a far larger area than it now possesses, for it covered much of the present lowlands and foot-hills along its northern border, and some of its important islands had not yet appeared or had not acquired their present dimensions.” ( On pages 1371-2 of Geikie’s “ Geology,” we find the following interesting passages : ~ “Alpine Type of Mountain Structure—It is along a great mountain chain like the Alps that the most colossal crumplings of the terrestrial crust are to be seen. In approaching such a chain, one or more minor ridges may be observed running on the whole parallel with it, as the heights of the Jura flank the north side of the Alps, and the sub-Himalayan hills follow the southern base of the Himalayas. On the outer side of these ridges, the strata may be flat or gently inclined. At first they undulate in broad gentle folds; but traced towards the mountains these folds become sharper and closer, their shorter sides fronting the plains, their longer slopes dipping in the opposite direction. This inward dip is often traceable along the flanks — of the main chain of mountains, younger rocks seeming to underlie others of much older date. Along the north front of the Alps, for instance, the red molasse is overlain by Eocene and older formations. The inversions and disruptions increase in magnitude till they reach such colossal dimen- sions as those of the Glarnisch, where pre-Cambrian schists, and Triassic, Jurassic, and Cretaceous rocks have been driven for miles over the Eocene and Oligocene flysch (pp. 677, 693). In such vast crumplings and thrusts it may happen that portions of older strata are caught in the folds of later formations, and some care may be required to discriminate the enclosure from the rocks of which it appears to form an integral and original part. Some of the recorded examples of fossils of an older zone occurring by themselves in a much younger group of plicated rocks may be thus ac- counted for. 1908.] THE PHYSICS OF THE EARTH. 235 “The inward dip and consequent inversion traceable towards the center of a mountain chain lead up to the fan-shaped structure (p. 678) where the oldest rocks of a series occupy the center and overlie younger masses, which plunge steeply under them. Classical examples of this structure occur in the Alps (Mont Blanc, Fig. 258, St. Gothard), where crystalline rocks such as granite, gneiss, and schists, the oldest masses of the chain, have been ridged up into the central and highest peaks. Along these tracts, denudation has been of course enormous, for the appearance of the granitic rocks at the surface has been brought out, not necessarily by actual extru- sion into the air, but more probably by prolonged erosion, which in these higher regions, where many forms of sub-aerial waste reach their most vigorous phase, has removed the vast overreaching cover of younger rocks under which the crystalline nucleus doubtless lay buried.” : ‘ H aie oe ‘ aie y) Ul ‘ aan} S ue / (i ‘Bre, Prue) ‘al 7 , ~ NN LEP LGN SEN | WWMiieenty SSN) MI WALA SSS! (less LZYGGG by SS) KR Fz ZH444 = Y = BS 4, Fic. 13. Fan-shaped Structure, Central Alps. Again on page 1372, we read: “A mountain chain may be the result of one movement, but probably in most cases is due to a long succession of such movements. Formed on a line of weakness in the crust, it has again and again given relief from the strain of compression by undergoing fresh crumpling and upheaval. Suc- cessive stages of uplift are usually not difficult to trace. The chief guide is supplied by unconformability. .. . “In most great mountain chains, however, the rocks have been so intensely crumpled, dislocated, and inverted, that much labor may be re- quired before their true relations can be determined. “The Alps offer an instructive example of a great mountain system formed by repeated movements during a long succession of geological periods. The central portions of the chain consist of gneiss, schists, granite, and other crystalline rocks, partly referable to the pre-Cambrian series, but some of which (Schistes lustrés, Biindnerschiefer) include metamorphosed Paleozoic, Secondary, and in some places, perhaps, even older Tertiary de- posits (pp. 802, 1099). It would appear that the first outlines of the Alps were traced out even in pre-Cambrian times, and that after submergence, and the deposit of Paleozoic formations along their flanks, if not over most of their site, they were reelevated into land. From the relations of the , 236 SEE—FURTHER RESEARCHES ON [April 24, Mesozoic rocks to each other, we may infer that several renewed uplifts, after successive denudations, took place before the beginning of Tertiary times, but without any general and extensive plication. A large part of the range was certainly submerged during the Eocene period under the waters of the wide sea which spread across the center of the Old World, and in which the nummulitic limestone and flysch were deposited. But after that period the grand upheaval took place to which the present magnitude of the mountains is chiefly due. The older Tertiary rocks, previously horizontal under the sea, were raised up into mountain-ridges more than 11,000 feet above the sea-level, and together with the older formations of the chain, underwent colossal plication and displacement. Enormous slices of the oldest rocks were torn away from the foundations of the chain and driven horizontally for miles until they came to rest upon some of the newest formations. The thick Mesozoic groups were folded over each other like piles of carpets, and involved in the lateral thrusts so as now to be seen resting upon the Tertiary flysch. So intense was the compression and shear- ing to which the rocks were subjected that lenticles of the Carboniferous series have been folded in among Jurassic strata, and the whole have been so welded together that they can hardly be distinguished where they meet, and what were originally clays and sands have been converted into hard crystalline rocks. It is strange to reflect that the enduring materials out of which so many mountains, cliffs, and pinnacles of the Alps have been formed are of no higher geological antiquity than the London Clay and other soft Eocene deposits of the south of England and the north of France and Belgium. At a later stage of Tertiary time, renewed disturbance led to the destruction of the lakes in which the molasse had accumulated, and their thick sediments were thrust up into large broken mountain masses, such as the Rigi, Rossberg, and other prominent heights along the northern flanks of the Alps. Since that last post-Eocene movement, no great orogenic paroxysm seems to have affected the Alpine region. But the chain has been left in a state of unstable equilibrium. From time to time normal faults have taken place whereby portions of the uplifted rocks have sunk down for hundreds of feet, and some of these dislocations have cut across the much older and more gigantic displacements of the thrust-planes (Fig. 282). At the same time continuous denudation has greatly transformed the surfaces of the ground, so that now cakes of gneiss are left as mountainous outliers upon a crushed and convoluted platform of Tertiary strata. Nor, in spite of the settling down of these broken masses, has final stability been attained. The frequent earthquakes of the Alpine region bear witness to the strain of the rocks underneath, and the relief from it obtained by occasional rents propagated through the crust along the length of the chain.” In view of the explanation of the folding of the Alps given in § 28, we need not comment on these views. They confirm the theory outlined in this paper, that the plications of all such chains must be sought in the actions of the sea, and mainly while the 1908. | THE PHYSICS OF THE EARTH. 237 range is under water, and not at all in the secular cooling of the globe. V. CoMPARISON OF THE OLD AND NEw THEORY OF MOUNTAIN FoRMATION CONTINUED. i (B) Views or EMINENT GEOLOGISTS oN MouNTAIN ForRMATION IN GENERAL, § 37. Elie de Beaumont’s Theory of the Secular Cooling and Collapse of the Globe-—This venerable theory is thus condensed by Lyell: . “The origin of these chains depends not on partial volcanic action or a reiteration of ordinary earthquakes, but on the secular refrigeration of the entire planet. For the whole globe, with the exception of a thin envelope, much thinner in proportion than the shell to an egg, is a fused mass, kept fluid by heat, but constantly cooling and contracting in dimensions. The external crust does not gradually collapse and accommodate itself century after century to the shrunken nucleus, subsiding as often as there is a slight failure of support, but it is sustained throughout whole geological periods, so as to become partially separated from the nucleus until at last it gives way suddenly, cracking and falling in along determirate lines of fracture. During such a crisis the rocks are subjected to great lateral pres- sure, the unyielding ones are crushed, and the pliant strata bent, and are forced to pack themselves more closely into a smaller space, having no longer the same room to spread themselves out horizontally. At the same time, a large portion of the mass is squeezed upwards, because it is in the upward direction only that the excess in size of the envelope, as compared to the nucleus can find relief. This excess produces one or more of those folds or wrinkles in the earth’s crust which we call mountain-chains.” De Beaumont’s theory is given more from its antiquity than from its present day importance, and yet in some form it stili holds its place in all our treaties on geology. Indeed the latest works include discussions of the strength of domes, as if the nucleus of the globe were shrinking away from the crust, and the latter thus subjected to crushing from its own weight. § 38. Views of Lyell—tThis great geologist always rejected Elie de Beaumont’s theories of mountain formation, and gave the most cogent reasons for his course. He adopted the theory that the land is occasionally depressed and elevated, by internal forces, but did not definitely decide what forces produced these progressive PROC. AMER. PHIL. SOC, XLVII. 189 P, PRINTED SEPTEMBER 23, 1908. 238 SEE—FURTHER RESEARCHES ON [April 24, or oscillatory movements of the earth’s crust. One of Lyell’s greatest disciples was Charles Darwin, whose views we shall now very briefly recall. § 39. Views of Charles Darwin.—The views of Darwin are very briefly and lucidly set forth by Professor Suess (“ Face of the Earth,” Vol. I, p. 104), as follows: “The earthquaké of February 20, 1835 (at Conception, Chili), gave rise to one of the most important works on the elevation of mountains, indeed I may say to the the only attempt, based on direct observation of nature, to establish more exactly the older theories concerning the force which is sup- posed to have raised up mountain chains. The author of this work is Charles Darwin. Since that time no second attempt, or at least no attempt of equal importance, has been made in this direction. To day, more than half a century later, it is possible to hold other opinions on these questions and yet to recognize the boldness of the generalization which even then revealed the master. “Darwin saw the awakening activity of the volcanoes during and after the earthquake; he believed he saw elevation, although not uniform eleva- tion of the solid ground; in addition he saw the terraces along the coast. But he also knew that similar terraces occur on the east coast of South America, where there are no volcanoes and no earthquakes. The earthquakes must therefore have appeared to his eyes as the local expression of a uni- versal force. The secular contraction of the earth, a theory already eagerly advocated by several investigators, Darwin justly held to be entirely un- suited to explain those intermittent elevations which the terraces betrayed, and thus he reached the conclusion: “* That the form of the fluid surface of the nucleus of the earth is sub- ject to some change, the cause of which is entirely unknown and the effect of which is slow, intermittent but irresistible?” § 40. Views of Professor James D. Dana.—The views of this eminent geologist have been carefully discussed in the paper on “The New Theory of Earthquakes and Mountain Formation as Illustrated by Processes Now at Work in the Depths of the Sea,” § 13. The reader is referred to that discussion. Here it must suffice to say that, although Dana recognized that there was a funda-_ mental relationship between the depth and extent of an ocean and the height of the mountains which surround it, he was unable to define this relationship except in very general terms, and could not assign any definite cause for the law which he pointed out. He considered the oceanic basins as subsiding, while the continents were being elevated. 1908. ] ' THE PHYSICS OF THE EARTH. 239 Though Dana’s views were somewhat modified by later study and investigation, he always maintained that “the principal moun- tain chains are portions of the earth’s crust which have been pushed up and often crumpled or plicated by lateral pressure resulting from the earth’s contraction.” In order to explain this supposed mode of action he held that the oceanic areas have been “the regions of greatest contraction and subsidence, and that their sides have been pushed like the ends of an arch, against the borders of the con- tinents.” Even with these arbitrary assumptions it is not at all clear how the settlement of the Pacific Ocean could elevate our great plateau west of the Rocky Mountains, which is nearly a thousand miles wide. If the subsidence of the ocean bed had pushed up the margin of North America, the crumpling and elevation of the land could not well extend one third of the way across the continent. We need not, however, be greatly surprised at this difficulty, for at best Dana’s theory is vague, and he evidently could not under- stand just how the elevation had come about. Yet so fully was Dana convinced of the dependence of the mountains on the oceans adjacent to them that he reduced it to calculation by the rule-of- three. He says: “The relation of the oceans to the mountain borders is so exact that the rule-of-three form of statement cannot be far from the truth. As the size of the Appalachians to the size of the Atlantic, so is the size of the Rocky chain to the size of the Pacific. Also, as the height of the Rocky chain to the extent of the North Pacific, so are the height and boldness of the Andes to the extent of the South Pacific.” (“Manual of Geology,” 1863, p. 25.) This was indeed a remarkably near approach to the great law of nature, that the mountains along the coasts are formed by the expulsion of lava from under the sea, and are, therefore, every- where proportional to extent and depth of the adjacent oceans. § 41. Views of James Hall.—In 1857 this distinguished Ameri- can geologist announced in a presidential address to the Ameri- can Association at Montreal, that the enormous depth of the sedi- mentation along the Appalachian chain was due to the prolonged accumulation of sediments along a sinking, off-shore line of sea bottom. He reached this view from the careful study of the 240 SEE—FURTHER RESEARCHES ON [April 24, Appalachian and other American mountain regions. To explain such deposits he supposed that marine currents had formerly traversed these regions and by gradually depositing sediments of great weight had also sunk the crust till at length a great thickness was attained. When the rocks thus formed had become solidified and crystallized the borders of the continent were afterwards up- raised somehow. He did not indicate how the uplift had come about, nor did he think that the mountain regions had been raised separately. Denudation had then commenced, and finally given the mountains the forms they have today. Keferstein, Sir John Herschel, Dr. T. Sterry Hunt and others, along with Hall, or even before him, in some cases, had de- veloped the theory of aqueo-igneous fusion, which was supposed to produce a plastic zone between the consolidated crust and the solid nucleus. This theory supposed that the isogeotherms rise in regions of heavy sedimentation. Hall held that this would “cause the bottom strata to establish lines of weakness or of least resis- — tance in the earth’s crust, and thus determine the contraction which results from the cooling of the globe to exhibit itself in those regions, and along those lines where the ocean’s bed is subsiding beneath the accumulated sediments.” Many of the views afterwards more fully developed by Leconte are here faintly traced by Hall, and for that reason these early views of mountain formation are worthy of attention. § 42. Views of Leconte——This veteran geologist gave great attention te mountain formation throughout a long career, and his residence on the Pacific Coast gave him exceptional facilities for studying the ranges of our western states, and especially of Cali- fornia, which includes the most remarkable developments in North America: The views at which Leconte arrived, as set forth in his “Elements of Geology,” edition of 1896, are as follows: “ Mountain Origin, “Leaving aside for the present all disputed points, it is now universally admitted that mountains are not usually pushed up by a vertical force from beneath, as once supposed, but are formed wholly by lateral pressure. The earth’s crust along certain lines is crushed together by lateral or horizontal pressure and rises into a mountain-range along the line of yielding, and to a height proportionate to the amount of mashing. But the yielding is not by rising into a hollow arch, nor into such an arch filled beneath with liquid 1908. | THE PHYSICS OF THE EARTH. 241 (for in neither case would the arch support itself), but by mashing together and in thickening and crumpling of the strata and an upswelling of the whole mass along the line of greatest yielding. That this is the immediate or proximate cause of the origin or elevation of mountains is plainly shown by their structure. As to the ultimate cause—i. e., the cause of the enormous lateral pressure—this lies still in the field of discussion. We shall discuss it briefly in its proper place” (pp. 261-2). Again, on page 264, we find this account: “Proof of Elevation by Lateral Pressure alone: 1. Folding—It is evi- dent that foldings such as those represented in all the above figures, and which occur in nearly all mountains, cannot be produced except by lateral pressure, and are therefore proof of such pressure. But, moreover, it can be shown that, when we take into consideration the immense thickness of mountain strata and the degree of folding, lateral pressure is sufficient to account for the whole elevation, without calling in the aid of any upward pushing from beneath. For example, the Coast range of California (Fig. 228) is composed of at least five anticlines and corresponding synclines. If eoeert termes, - s+ oo" by. ., eowren. Pal Ses, 2 “Peenn ceo” ss a. : - — Mscnccnucse*> ‘ . as, ‘ ‘, £ / Fic. 14. Section of a Portion of the Alps. its folded strata were spread out horizontally in the position of the original sediments, they would undoubtedly cover double the space. Now, supposing the strata here are only 10,000 feet thick—a very moderate estimate—in mashing to one half the extent, they would be thickened to 20,000 feet, which would be a clear elevation of 10,000 feet if they were not subsequently eroded. According to Renevier, a section of the Alps reveals seven anticlines and corresponding synclines, and some of them are complete overfolds (Fig. 230). Weare safe in saying that Alpine strata have been mashed horizontally into one half their original extent. Supposing these were originally 30,000 feet thick (they were really much thicker), this would make a clear eleva- tion of 30,000 feet. Of course, most of this has been cut away by erosion. In the Appalachian range, according to Claypole, the foldings are so extreme that in one place 95 miles of original extent have been mashed into 16 miles, or six into one, and yet the Appalachian strata are estimated as 40,000 feet thick. Cases of still greater doubling of strata upon themselves occur. In 242 SEE—FURTHER RESEARCHES ON [April 24, the Highlands. of Scotland the strata by lateral thrust were broken and slidden one over another for ten miles. In the Canadian Rocky Mountains there is an overthrust of seven miles, by which the Cambrian is made to override the Cretaceous, and 50 miles of strata are mashed into 25 miles (McConnell). In the Appalachians of Georgia the Rome fault is an over- thrust which brings the Cambrian in contact with the Carboniferous and the fault under different names may be traced northward for 275 miles; and in the Cartersville thrust-fault there is an overriding of 11 miles (Hayes). The manner in which this is done is illustrated on a previous page (Fig. 209). Evidently, then, the whole height of the mountains mentioned above is due to lateral crushing alone.” If Professor Leconte had been familiar with the folding pro- duced in the sea trenches he could have completed the theory of mountain formation developed in this paper. As geologists have for centuries recognized the fossils found in mountains as having been deposited in the sea, it is remarkable that the suggestion seems never to have occurred to them that the folding was done in the sea before the land was lifted above the water, and by earthquake proc- esses due to the sea itself. Leconte, however, came very near this view, as the following will show (p. 267 et seq.) : “ Mountains are made out of lines of thick sediments.—But the question occurs, What determines the place of a mountain-range? The answer is, A mountain-range while in preparation—before it became a range—was a line of very thick sediments. This is a very important point in the theory of mountain origin, and therefore must be proved. The strata of all moun-' tains, where it is possible to measure them, are found to be of enormous thickness. The strata involved in the folded structure of the Appalachian, according to Hall, are 40,000 feet thick, the strata exposed in the structure of the Wahsatch, according to King, are more than 50,000 feet thick; the Cretaceous strata of the Coast Range, near the Bay of San Francisco, according to Whitney, are 20,000 feet thick; and if we add to this 10,000 feet for the Eocene and Miocene strata, the whole thickness is probably not less than 30,000 feet, while the Cretaceous alone in Northern California, according to Diller, is 30,000 feet. The Alpine geologists estimate the thickness of the strata involved in the intricate structure of the Alps as 50,000 feet. The strata of Uintah, according to Powell, are 32,000 feet thick. “Now, it must not be imagined that these numbers merely represent the general thickness of the stratified crust; only that in these places the strata are turned up and their edges exposed by erosion, and thus their thickness revealed. On the contrary, it may be shown that the same strata are much thinner elsewhere. The same strata which along the Appalachian range are 40,000 feet thick, when traced westward thin out to 4,000 feet at the Mississippi River. The same strata which along the line of the Wah- 1908.] THE PHYSICS OF THE EARTH. 243 satch are 30,000 feet thick, when traced eastward thin out to 2,000 feet in the region of the plains. It is evident, therefore, that mountain-ranges are lines of exceptionally thick strata. “ Mountain-ranges were once Marginal Sea-Bottoms.—Where, then, do sediments now accumulate in greatest thickness? Evidently on marginal sea- bottoms, off the coasts of continents. The greater part of the washings of continents are deposited within 30 miles of shore, and the whole usually within 100 miles. From this line of thickest and coarsest deposit the sedi- ments grow thinner and finer as we go seaward. But evidently such enor- mous thicknesses as 40,000 feet cannot accumulate in the same place with- out pari passu subsidence such as we know takes place now whenever exceptionally abundant sedimentation is going on (p. 145). Therefore, mountain-ranges before they were yet born—while still in preparation as embryos in the womb of the ocean—were lines of thick off-shore deposits gradually subsiding, and thus ever renewing the conditions of continuous deposits. “As this is a very important point, it is necessary to stop here awhile in order to show that such was actually the fact in the case of all the principal ranges of the American Continent—i. e., that for a long time before they were actually formed, the places which they now occupy were marginal sea-bottoms receiving abundant sediments from an adjacent continent. We shall be compelled to anticipate some things that belong to Part III, but we hope to make statements so general that there will be no difficulty in under- standing them. * “y, Appalachian—The history of this range is briefly as follows: At the beginning of the Paleozoic era there was a great V-shaped land-mass, occupying the region now covered by Labrador and Canada, then turning northwestward from Lake Superior and extending perhaps to polar regions about the mouth of the Mackenzie River. This is shown on map, Fig. 260, on page 303. There is another great land-mass occupying the present place of the eastern slope of the Blue Ridge and extending eastward probably far beyond the present limits of the continent—as shown in the same figure by dotted line in the Atlantic Ocean. The western coast-line of this land- ‘mass was the present place of the Blue Ridge. Westward of this line extended a great ocean—‘the interior Paleozoic Sea.’ The Appalachian range west of the Blue Ridge was then the marginal bottom of that sea. During the whole of the Cambrian, Silurian, and Devonian, this shoreline remained nearly in the same place, although there was probably a slow transference westward. Meanwhile, throughout this immense period of time, the washings from the land-mass eastward accumulated along the shore-line, until 30,000 feet of thickness was attained. At the end of the Devonian some considerable changes of physical geography of this region took place, which we will explain when we come to treat of the history of this period. Suffice it to say now that during the Carboniferous the region of the Appalachian was sometimes above the sea as a coal-swamp, and sometimes below, but all the time receiving sediment until 9,000 or 10,000 feet more of thickness was added, and the aggregate thickness became 244 SEE—FURTHER RESEARCHES ON [April 24, 40,000 feet. Of course, it is impossible that such thickness could accumulate on the same spot without pari passu subsidence of the sea-floor. In fact, we have abundant evidences of comparatively shallow water at every step of the process—evidence sometimes in the character of the fossils, some- times in the form of shore-marks of all kinds, sometimes in the form of seams of coal, showing even swamp-land conditions. Again, of course, the sediments were thickest and coarsest near the shore-line, and thinned out and became finer towards the open sea, i. e., westward. Finally, after 40,000 feet of sediments had accumulated along this line the earth-crust in this region gave way to lateral pressure, and the sediments were mashed together and folded and swollen up into the Appalachian range. Subsequent erosion has sculptured it into the forms of scenic beauty which we find there to-day. 2. Sierra.—This was apparently the first-born of the Cordilleran family. Its history is as follows: During the whole Paleozoic and earlier part of the Mesozoic, there was in the Basin region a land-mass, whose form and dimensions we yet imperfectly know, but whose Pacific shore-line was east of the Sierra. The Sierra region was therefore at that time the marginal bottom of the Pacific Ocean. Probably the position of this shore line changed considerably at the end of the Paleozoic. The extent of this change we will discuss hereafter. Suffice it to say now that, during the whole of this time, the Sierra region received sediments from this land-mass until an enormous thickness (how much we do not know, because the foldings are too complex to allow of estimate) was accumulated. At last at the end of the Jurassic, the sea floor gave way to the increasing lateral pressure along the line of thickest sediments, and these latter were crushed together with complex foldings and swollen up into the Sierra. An almost incon- ceivable subsequent erosion has sculptured it into the forms of beauty and grandeur which characterize its magnificent scenery. “3 Coast Range—The birth of the Sierra transferred the Pacific shore- line westward, and the waves now washed against the western foot of that range, or possibly even father westward in the region of the Sacramento and San Joaquin plains. At this time, therefore, the region of the Coast Range was the marginal bottom of the Pacific Ocean. During the whole Cretaceous, Eocene, and Miocene, this region received abundant sediments from the now” greatly enlarged continental mass to the eastward; until finally, at the end of the Miocene, when 30,000 feet of sediments had accumulated along this line, the sea-floor yielded to the lateral pressure, and the Coast Range was born; and the coast-line transferred to near its present position. “4. Wahsatch—The physical geography of the region to the east of the Wahsatch (Plateau region) during Jura-Trias time is little known. But during the Cretaceous the region of the Wahsatch was the western marginal bottom of the great interior Cretaceous Sea (see map, Fig. 760, p. 486), receiving abundant sediments from the great land-mass of the Basin and Sierra region, This greatly increased the enormous thickness of sediments already accumulated along this line in earlier times. At the end of the Cretaceous the sediments yielded, and the Wahsatch was born. It is neces- sary, however, to say that both the Sierra and Wahsatch underwent very 1908. ] THE PHYSICS OF THE EARTH. 245 great changes of form produced by a different process and at a much earlier period. We shall speak of this later. “5. Alps—Mr. Judd has recently shown that the region of the Alps, during the whole Mesozoic and Early Tertiary, was a marginal sea bottom, receiving sediments until a thickness was attained not less than that of the Appalachian strata. At the end of the Eocene these enormously thick sedi- ments were crushed together with complicated foldings and swollen upward to form these mountains and afterward sculptured to their present forms. “The same may be said of the Himalayas and nearly all other moun- tains. We may, therefore, confidently generalize, and say that the place now occupied by mountain-ranges have been previous to their formation, places of great sedimentation, and therefore usually marginal ocean bottoms. In some cases, however, the deposits in interior seas or mediterraneans have yielded in a similar way, giving rise to more irregular ranges or groups of mountains.” ... “Why thick Sediments should be Lines of YVielding—Admitting, then, that mountains are formed by the squeezing together of lines of very thick sediments, the question still occurs, Why does the yielding take place along these lines in preference to any others? This is a capital point in the theory of mountain formation. The answer is as follows: We have already seen (p. 231) that accumulation of sediments causes the isogeotherm to rise and the interior heat of the earth to invade the lower portion of the sedi- ments with their included waters. Now this invasion of heat in its turn causes hydrothermal softening or even fusion, not only of the sediments, but also of the sea-floor on which they rest. Thus a line of thick sediments becomes a line of softening and therefore a line of weakness, and a line of yielding to the lateral pressure, and therefore a line of mashing together and folding and upswelling—in other words a mountain-range. As soon as the yielding commences we have an additional source.of heat in the crush- ing itself. In addition to this, upheaval by lateral crush by the tendency to arch the strata would produce relief of gravitative pressure, and there- fore fusion (p. 103). It follows from this that there is or was beneath every mountain a line of fused or semi-fused matter. This we will call the sub-mountain liquid. This by cooling and solidification becomes a meta- morphic or granitic core, which by erosion forms the metamorphic or granitic axis and crest of many great mountains”... (pp. 271-2). “Cause of Lateral Pressure—We have thus proved that the immediate cause of the origin and the growth of mountains is lateral pressure acting on thick sediments, crushing them together and swelling them up along the line of great thickness. But still the question remains, What is the ultimate cause, 1. e., thé cause of the lateral pressure? This, as we have already said, lies still in the domain of doubt and discussion, but the view which seems most probable may be briefly stated as follows: “Tn the secular cooling of the earth there would be not only unequal radial contraction, giving rise, as shown on page 175, to continents and ocean-basins, but also to unequal contraction of the exterior as compared with the interior. At first, and for a long time, the exterior would cool 246 SEE--FURTHER RESEARCHES ON [April 24, fastest; but there would inevitably, sooner or later, come a time when the exterior, receiving heat from abroad (sun and space), as well as from within, would assume an almost constant temperature, while the interior would still continue to cool, and contract. Thus, therefore, after a while the interior nucleus would contract faster than the exterior shell. It would do so, partly because it would cool faster, and partly because the coefficient of contraction of a hot body is greater than that of a cooler body. Now, as soon as this condition was reached, the exterior shell, following down the shrinking nucleus, would be thrust upon itself by a lateral or horizontal pressure which would be simply irresistible. If the earth’s crust were a hundred times more rigid than it is (thirty times as rigid as steel, 500 to 1,000 times as rigid as granite—Woodward, Science, Vol. XIV, p. 167, 1889), it must yield. Mountain-ranges are the lines along which the yielding takes place, and this yielding takes place along the lines of thick sediments be- cause these are lines of weakness. “There are several serious objections which may be brought against this view: 1. Calculations seem to show that. the amount of crumpling and folding actually found in the mountains is many times greater than could be produced by the contraction of the earth by cooling. But it may be answered (1) that the calculations take no account of the greater coefficient of contraction at high temperatures, and therefore at great depths, (2) and that there may be other causes of contraction besides cooling. For example, loss of constituent gases and vapors from the interior of the earth, through volcanic vents and fissures, has been suggested by O. Fisher (p. 102). “2. Again, it has been shown by Dutton that it is impossible that the effects of differential contraction should be concentrated along certain lines, so as to give rise to mountain-ranges without a shearing of the crust upon the interior portions, which is inadmissible if the earth be solid. Instead, therefore, of conspicuous mountain-ranges, the effects of differential con- traction would be distributed all over the surface, and be wholly impercep- tible. But in answer to this it may be said that there is no difficulty in the way of shearing, and therefore of such concentration of effects along certain lines, if there be a sub-crust liquid or semi-liquid layer, either universal or else underlying large areas of surface. “ Still other objections have been raised, but these are so recent that they have not yet been sufficiently sifted by discussion to deserve mention here.’ The origin of mountains by lateral pressure is a fact beyond dispute. This is the most important fact for the geologist. How the lateral pressure is pro- duced is a pure physical question which must be left to the physicists to settle among themselves” (pp. 274-5). Leconte treats also of Monoclinal mountains, as found in the Great Basin, which he explains by normal faulting, or vertical move- ment of crust blocks, and finally adds: *For a completer discussion of this subject, see “ Theories of Mountain Origin,” Jour. Geol., Vol. L., p. 542, 1893. 1908. | THE PHYSICS OF THE EARTH. 247 “Thus, then, there are two types of mountains strongly contrasted, mountains of the one type are formed by lateral pressure and crushing, of the other type by lateral tension and stretching. The one gives rise mainly to reverse faults, the other always to normal faults.’ Mountains of the one type are formed by upswelling of thick sediments, those of the other type by irregular readjustment of crust-blocks. Mountains of the one type are born of the sea, those of the other type are born on the land. We find examples of the one type in nearly all the greatest mountains everywhere, but especially in the Appalachian, the Alps and the Coast Range. The best examples, perhaps the only examples, of the other type are the Basin ranges. Some mountains, as the Sierra, the Wahsatch, and certainly some of the Basin ranges, belong to both types. In their origin, they have formed in the first way, but afterward have been modified by the second way. Thus the first is the fundamental method, and the second only a modifying proc- ess” (p. 277). These views of Leconte call for no special comment, beyond the remark that normal faulting itself is wholly unexplained. If secu- lar cooling were the cause, such faults ought to occur east of the Rocky Mountains as well as west of them. The important differ- ence is that the Pacific Ocean was on the west pushing up the land, and a continental basin on the east, either dry or covered by shallow water and therefore doing little or no pushing at all. In any case the great plateaus of the west were certainly uplifted by the Pacific, through the expulsion of lava under the land. In the Andes of South America the plateaus are higher indeed, but also narrower than those in North America, because in our continent the relief resulting from the leakage of the ocean took a broader and less ele- vated form. It is impossible for any one to doubt the identity of the forces which raised the Andes and their plateaus, the Himalayas and their plateaus, and the Rocky Mountains and the mountains and plateaus of the Great Basin. The principle of continuity shows clearly that the cause was everywhere one and the same. Several American geologists have suggested vertical uplifts in the Great Basin, from the way in which the crust blocks are displaced; but heretofore no known cause for such movements could be assigned, because it was held that secular cooling is the chief if not the only cause operating in the development of the globe. § 43. Views of Rev. O. Fisher—The Rev. O. Fisher was the first to show by long and patient research the total inadequacy of secular cooling to account for the observed height of mountains. 248 SEE—FURTHER RESEARCHES ON [April 24, He showed that the mountains are hundreds of times higher than the cooling of the earth will explain. On this point his labors mark a distinct advance in geological science; for next in importance to establishing true theories is the overthrow of erroneous ones, which clears the ground for a fresh start. But notwithstanding the un- answerable character of Fisher’s argument, the old theories have been retained by geologists as the best they could devise. Fisher’s criticisms of geological theories are carefully thought out, and worthy of attention. He has always denied the entire solidity of the earth, holding that the movements noticed in mountains proved the existence of a mobile substratum beneath a crust some twenty miles thick. Here again he was certainly right, and it is difficult to see how such an obvious proposition could be denied. We need not dwell on Fisher’s views of mountain formation, because they imply convection currents within the earth, and these latter are certainly inadmissible, except just beneath the crust in earthquake movements, as developed in the theory set forth in this paper. § 44. Views of Major C. E. Dutton,—Like the Rev. O. Fisher, Major Dutton was one of the earliest authorities to question the adequacy of secular cooling to account for the wrinklings noticed in the earth’s crust. Using the results of Fourier’s solution for the variation of temperature, as developed in the work of Lord Kelvin, Dutton found that “the greatest possible contraction due to secular cooling is insufficient in amount to account for the phenomena attributed to it by the contraction hypothesis. By far the larger portion of this contraction must have taken place before the commencement of the Paleozoic age. By far the larger portion of the residue must have occurred before the beginning of the Terti- ary, and yet the whole of this contraction. would not be sufficient to account for the disturbances which have occurred since the close of the Cretaceous.” Major Dutton concludes that “the determination of plications to particular localities presents difficulties in the way of the contrac- tional hypothesis which have been underrated.” He held that the localization of the plications could result only from a large amount of horizontal slipping of the crust over the nucleus, and the friction involved in this movement even over a liquid nucleus would be so great as to render the assumption a physical absurdity. 1908.] THE PHYSICS OF THE EARTH. 249 If wrinkling resulted from ‘uniform cooling and consequently uniform shrinkage, the effect would be analogous to that of a with- ered apple, with small wrinkles all over it, instead of a surface presenting in one region a continuous system of folds extending from Cape Horn to Alaska, and in another, a zone a thousand miles wide, from the Appalachian to the Rocky Mountains, with scarcely any evidence of disturbance whatever. In these considerations Major Dutton has forcibly expressed the difficulty of supposing that a mountain range is formed by the cooling of the earth contracting equally along all its radii. Such a supposed mode of formation of our ranges, folded and crumpled as they are, is clearly impossible; and Major Dutton shares with the Rev. O. Fisher the credit of having been the first to recognize the total inadequacy of the contraction theory. It is remarkable that after this antiquated theory had been thus clearly disproved, it should have continued in use. No one seems to have been able to frame a theory based on any cause except secu- lar cooling, till the present writer developed the theory based on the leakage of the oceans and the formation of mountains by the expul- sion of lava under the land, which perfectly explains all the phenomena. § 45. Views of Geikie—In the article “ Geology,” Encyclopedia Britannica, p. 375, we find the following statement of the contrac- tion theory: ‘There still remains the problem to account for the original wrinkling of the surface of the globe, whereby the present great ridges and hollows were produced. “Tt is now generally agreed that these inequalities have been produced by unequal contraction of the earth’s mass, the interior contracting more than the outer crust, which must therefore have accommodated itself to this diminution of diameter by undergoing corrugation. But there seems to have been some original distribution of materials in the globe that initiated the depressions on the areas which they have retained. It has been already pointed out (ante, p. 223) that the matter undertying the oceans is more dense than that beneath the continents, and that, partly at least, to this cause must the present position of the oceans be attributed. The early and per- sistent subsidences of these areas, with the consequent increase of density, seems to have determined the main contours of the earth’s surface. .. . “The effects of this lateral pressure may show themselves either in broad dome-like elevations, or in narrower and loftier ridges of mountains. 250 SEE—FURTHER RESEARCHES ON [April'a, The structure of the crust is so complex, and the resistance offered by it to the pressure is consequently so varied, that abundant cause is furnished for almost any diversity in the forms and distribution of the wrinkles into which it is thrown. It is evident, however, that the folds have tended to follow a linear direction. In North America, from early geological times, they have kept on the whole on the lines of meridians. In the Old World, on the contrary, they have chosen diverse trends, but the last great crumplings —those of the Alps, Caucasus, and the great mountain ranges of central Asia—have risen along parallels of latitude. “Mountain chains must therefore be regarded as evidence of the shrink- age of the earth’s mass. They may be the result of one movement, or of a long succession of such movements. Formed on lines of weakness in the crust, they have again and again given relief from the strain of compression by undergoing fresh crumpling and upheaval.” Geikie’s views may be considered the accepted views of geolo- gists generally, and it will be seen that they rest on the theory of contraction due to secular cooling. On the constitution of the globe Geikie quotes (“ Geology,” p. 73) from the paper of Arrhenius, “ Zur Physik des Vulcanismus ” (1900), the following theory of the illustrious Swedish physicist : “Tf the rocks at the earth’s surface have a density half that of the globe as a whole, and if the density continues to hold good for the magma that arises from the melting of these rocks, we must conceive the existence of a much denser substance in the earth’s interior. On various grounds, such as the preponderance of iron in nature, both in meteorites and in the sun, and the phenomena of terrestrial magnetism, it may be inferred that this substance is metallic iron. In consequence of its greater density this iron will naturally be deeper than the rock magma, and on account of the high temperature must exist in a gaseous condition. Somewhere about a half of the planet therefore should consequently consist of Tron, and of other metals mingled with it in smaller proportions. The semi-diameter of this gaseous iron-sphere will thus include about 80 per cent. of the earth’s semi-diameter. Then will come about 15 per cent. of the gaseous rock magma, next to it the liquid rock-magma for a thickness of about 4 per cent. of the terrestrial semi-diameter, and lastly the solid crust, for which not more than I per cent. may be claimed” (pp. 404-5). Referring to the light thrown on the constitution of the interior by the observation of waves propagated by earthquakes, Geikie also ~ adopts the theory of Arrhenius, which is as follows: “The density of much the largest part (reckoned linearly) of this interior, amounting, as above stated, to about 80 per cent. of the radius, must be nearly three times higher than that of quartz. Since now the mean velocity of transmission of earthquake waves in the interior of the 1908.] THE PHYSICS OF THE EARTH. 251 earth has been ascertained to amount to 11.3 kilometers per second, the compressibility of that region must be 31 times less than that of quartz, that is, eight times less than that of solid steel, according to Voigt. This is a figure of precisely that order of magnitude which was to be expected. We may well believe that at depths of more than 1,000 kilometers the com- pressibility of gaseous iron sinks down to some ten times less than that of steel. “The interior of the earth, therefore, with the exception of a solid crust about 40 kilometers thick, consists of a molten magma 100 or 200 kilometers in depth which shades continuously inward into a gaseous center. The liquids and gases in the interior possess a viscosity and incompressi- bility such as permit them to be regarded as solid bodies. From these, however, they are distinguished in the first place by the fact that differentia- tions are possible to a considerable degree, the effects of which may long endure. In the second place, long continued, pressures, when acting on a large enough scale, may produce great deformations. Further, the liquids must possess the property of great expansion on a diminution of the high pressure, thereby readily becoming fluid. The process must thus differ but little from a normal melting with increase of volume, and especially of fluidity, as well as with absorption of heat. And yet the condition of aggre- gation is not thereby altered.” Geikie remarks that the theory of Arrhenius accords well with geological requirements: “With reference to the crust of the earth, it meets the constantly re- peated objections of the geologists to whom the existence of a comparatively thin crust has always seemed an essential condition for the production of that crumpled and fractured structure which the rocks of the land so uni- versally present. If the solid crust of the earth is allowed to be about 25 miles thick, we must conceive that in the lower four fifths of its mass the rocks are in a condition of latent plasticity. They lie much beyond the crushing strength which they exhibit at the surafec. They are not crushed into powder as they would be under a similar strain above ground, but they are ready to yield to the deformation$ that may arise consequent upon ad- justments of the gigantic pressure to which they are subjected. Hence the solid crust down as far as its structure has been disclosed abounds in proofs that it has undergone colossal plication and fracture, and that higher por- tions of it many square miles in extent have been thrust bodily over each other for many miles.” The last view here expressed by Geikie as to how the crust becomes thrust over itself for many miles is not, we think, well founded, because it is shown in this paper that all this folding and overlapping of the crust arises in the trenches dug out in the sea bottom by earthquakes. This crumpling and overthrusting of the crust certainly would not arise except for earthquakes produced by 252 SEE—FURTHER RESEARCHES ON [April 24, the leakage of the oceans, to which mountain formation is due. Of course the plasticity of this layer beneath the crust contributes to the final result, but the leakage of the oceans, with the resulting earthquakes, supplies the deforming force. § 46. Views of Professor Suess.—In the “ Face of the Earth” (Vol. I, p. 107) we find the following brief exposition of Professor Suess’ views: “The dislocations visible in the rocky crust of the earth are the result of movements which are produced by a decrease in the volume of our planet. The tensions resulting from this process show a tendency to resolve them- selves into tangential and radial components, and thus into horizontal (7. ¢., thrusting and folding), and into vertical (7. e., sinking) movements. Dis- locations may therefore be divided into two main groups, of which one is produced by the more or less horizontal, the other by the more or less vertical relative displacement of larger or smaller portions of the earth’s crust. ; “There are large areas in which the first, and others in which the second group predominates, and there are also regions in which both groups appear together, and in which an intimate connection may be recognized between them, the resolution of the movements in space having in these cases been less compléte. This essential difference in the movements of the lithosphere may be clearly perceived from a comparative study of the struc- ture of the Old World; nor has it escaped the notice of American geologists. “The geological provinces of the Great Basin,’ remarks Clarence King, has suffered two different types of dynamic action: one in which the chief factor was evidently tangential compression, which resulted in contraction and plication, presumably in post-Jurassic time; the other of strictly verti- cal action, presumably within the Tertiary, in which there are few evidences or traces of tangential compression.’ “Our colleagues on the other side of the ocean have even gone a great deal further. After comparison of the folded Appalachian mountains with the depressed Basin Ranges, Gilbert had in 1875 already suggested the possibility that in the Appalachians the causes of movement were superficial, in the Basin Ranges deep-seated. We shall have an opportunity, when dis- cussing the relation of the Alps to their northern foreland, of determining to what extent this supposition finds confirmation in Europe. We may how- ever state at once that as a rule it is only the dislocations of the second group which are accompanied by volcanic eruptions.” § 47. Views of Arrhenius—It is well known that this distin- guished Swedish fhysicist holds that the earth’s interior is essen- tially gaseous (cf. § 45, above), but under the great pressure oper- ating in the globe made to behave very nearly as a solid.t In his *See Postscript, page 274. 1908,] THE PHYSICS OF THE EARTH. 253 paper “ Zur Physik des Vulcanismus,” published in 1900, Arrhenius points out that in fluids at high temperature, where no increase in volume takes place, the internal friction of the molecules rises with the temperature, so that the viscosity increases and the fluidity diminishes; that a similar effect is observable in both gases and liquids ; that although gases have the highest and solids the lowest compressibility, nevertheless when a gas near its critical tempera- ture passes into a liquid, through a trifling physical change, there is practically no change in the compressibility. The higher the pressure the smaller is the compressibility, and a gas above the critical temperature may be made to acquire the properties of a solid by pressure alone. Such a mass has great density, small com- pressibility, and large viscosity, so that it has the properties of a solid, though really an imprisoned gas. : At a depth of 40 kilometers Arrhenius says the temperature is about 1200° C., and the pressure about 10,840 atmospheres; and as these conditions would render nearly all ordinary minerals fluid, he concludes that below that depth the matter is molten, ia the form of a magma—that is, a viscous and nearly incompressible liquid made to act nearly as a solid by pressure. At greater depths the temperature is above the critical tempera- ture of every known substance, as the pressure rapidly increases and the liquid magma becomes a gaseous magma with larger and larger viscosity, and smaller and smaller compressibility—in other words, an elastic solid with rigidity increasing with the depth. VI. ABANDONMENT OF THE OLD THEORIES OF THE PHYSICS OF THE EARTH. § 48. The Total Inadequacy of the Old Theories to Account for the Fault Movements near the Sea, which Raise Vertical Blocks and Walls of Granite Thousands of Feet above the Water.—The vast * Andesite is the name used to designate the kind of granitic rock found in the Andes. Charles Darwin showed that all granitic rocks are closely related. In his “ Text-book of Geology,” edition of 1903, book II, Part II, §7, pp. 230-260, Sir Archibald Geikie gives tables of the chemical compo- sitions of all these rocks, which show very clearly their close relationship. When we use the term granite therefore we mean granitic rock in the wide sense. PROC. AMER, PHIL. SOC. XLVII. 189 Q, PRINTED SEPTEMBER 24, 1908. 254 SEE—FURTHER RESEARCHES ON [Apiied: vertical walls and blocks of granite so often lifted thousands of feet above the sea, with deep water all around their bases, frequently encountered in different parts of the world, cannot be explained except by the present theory. Thus along the west coast of Chili and Patagonia, from Cape Horn to Valparaiso, in the Straits of Magellan, as well as in the ranges of the Andes further from the coast, in the Sierras of California, and elsewhere these vertical uplifts are common. It is obvious that they cannot possibly be explained by the old theories depending on the shrinkage of the globe. But if lava is expelled from beneath the sea, owing to the secular leakage of the ocean bottom, and the crust is “fractured and rent into blocks by the earthquake forces, some of these blocks would naturally be pushed upward, leaving vertical walls of granite thou- sands of feet high. Occasionally the blocks would be forced apart, leaving the sea pass between, as so often seen in Chili, Patagonia and Tierra Del Fuego. The Straits of Magellan no doubt arose in this way. As already remarked in § 27, Darwin describes similar breaks in the Andes further north, through which the sea once flowed, but they are now raised above the water. No doubt the time will come when Tierra Del Fuego will be joined solid to Pata- gonia, by uplifts which will cause the sea to withdraw from the Straits of Magellan and it will become dry land, like those ancient passages further north mentioned by Darwin. There are many other parts of the world where similar phenom- ena may be seen. The origin of the fiords in Norway has long been a matter of debate. It seems to be conceded that these inlets are made by mountains running into the sea, and more or less modified above water by ice and glaciers. They are supposed to be quite old, and certainly date back of the glacial epochs. It may no doubt be safely assumed that these Norwegian moun- tains originated, like other mountains, by the uplift of faults, owing to the expulsion of lava from beneath the sea.t_ Hence the precipiti- ous walls along the sea coast, with deep water between. The blocks * Having read the earlier papers of this series with great interest, Pro- fessor Schiaparelli has kindly called my attention to the trough in the sea along the Norwegian coast. This confirmation of the theory by the illustrious astronomer of Milan is exceedingly interesting. -1908.] THE PHYSICS OF THE EARTH. 255 of the earth’s crust were lifted vertically by the pushing of lava — beneath them. It is in this way that all such walls of granite and other towering rock are to be explained, and the fact that the sea still encroaches on them shows how the movements came about. Probably there has been little vertical movement for a long time along the coast of Norway, and subsidence as well as elevation may have taken place, both here and elsewhere. Subsidence is common along most sea coasts, but it does not prevail’ in the long run, as is proved by Professor Suess’s work, showing a universal lowering of the strand line throughout the world. § 49. The Theory of Arches and Domes Inapplicable to the Crust of the Earth, because the Globe is not Shrinking but actually Ex- panding.—In, Chamberlin and Salisbury’s “ Geology,” Vol. I, p. 583, we find the statement that “The principle of the dome is brought into play whenever an interior shell shrinks away, or tends to shrink away, from an outer one which does not shrink. In this case there is a free outer surface and a more or less un- supported under surface towards which motion is possible. The dome may, therefore, yield by crushing or by contortion.” Owing to the important part the domed form of the crust has played in theories of deformation, these authors give quantitive results calculated by Hoskins, showing that such a dome of continental dimensions, if unsupported from below, would sustain only 1/525th of its own weight. In his consideration of the “ Mathematical Theories of the Earth” (Proc. Am. Assoc. for Adv. Sci., 1889, p. 49), Professor R. S. Woodward reached the analogous conclusion that “If the crust of the earth were self-supporting, its crushing strength would have to be about thirty times that of the best cast steel, or five hun- dred to one thousand times that of granite.” In view of these results it is remarkable that any one should have viewed the earth’s crust as a wholly or partially self-support- ing dome; for it could not be supported even over a very small area. And moreover secular cooling is wholly inadequate to cause a separation of the interior layers from the crust. All that has been . published on this point, therefore, is inapplicable to the earth, be- _ cause it rests on a false hypothesis. The supposed conditions have no reality: 256 SEE—FURTHER RESEARCHES ON [April 24, The earth is not shrinking and the crust does not tend to sepa- rate itself from the underlayers, except where the lava has been expelled from beneath it by earthquakes. The collapse of the crust when thus undermined, howeVer, shows that it will not support its own weight even for a short distance. Over such small areas the crust may be taken as part of a plane, or sometimes as concave, where subsidence is already at work, and hence the theory of the arch or dome is scarcely applicable; yet the observed collapse and sinking, even where the area is no larger than in ocean troughs, confirms the above conclusions regarding the total inability of the crust to support itself. Could therefore anything be more absurd than to discuss the stresses in the crust due to the progress of secular cooling? Stresses arise only where mountain making is in progress, and therefore chiefly near the oceans, but never appear far inland; and are wholly due to the pressure arising from steam-saturated rock and the expul- sion of lava from beneath the oceans, or to movements traceable to surface water slowly sinking into the earth. The theory of arches and. domes therefore confirms the present theory, but this result is— indirect; and such lines of thought did*not enable geologists and physicists to reach correct conceptions regarding the physics of the earth’s crust. § 50. On the Doctrine that Earthquake Movements depend on Slight Inequalities of Loading, and on the Abandoned Theory that the Earth is a Failing Structure.—As the crust of the earth is made up of solid rock and soil arising from the disintegration of rock of various kinds, and as this material is elastic and yields under pres- sure, it naturally occurred to physicists that inequalities of surface loading deposited on adjacent areas would impose upon the under- lying crust unequal stresses, and perhaps give rise to relative move- ments. Thus many physicists, in default of a better theory, have supposed that surface loads, depending on erosion and sedimenta- tion, tides and varying barometric pressure, would be adequate to produce stresses that would cause readjustment of the surface strata and perhaps movements of faults in earthquakes. It is undeniable that these varying loads do produce some small effects, and very slight changes of level may often arise in this 1908, ] THE PHYSICS OF THE EARTH. 257 way. We owe the establishment of these effects of loading chiefly to the researches of Professor Sir G. H. Darwin, whose labors have so greatly advanced our knowledge of the physics of the earth. They have an extremely high importance in the theory of bodies approximating elastic solids. The undisturbed crust of the globe fulfills these conditions quite perfectly. But to suppose that any of these small surface effects could give rise to world-shaking earthquakes which would shake down cities, raise sea coasts, and uplift mountains and islands in the sea, is too severe a test of credulity to be entertained. The class of minute movements, due to surface yielding under varying loads depending on sediments, tides and meteorological causes, and the class of great movements, due to the expulsion of lava from under the bed of the sea, are quite distinct. One class of these phenomena is micro- seismic, the other magaseismic. Previous investigators have gen- erally confounded the two classes of phenomena, and hence they have been unable to recognize the true cause of earthquakes and mountain formation. For that reason it was necessary to restrict our investigation to the great disturbances, in the first search for the cause of the great movements of the earth’s crust. We repeat that both classes of phenomena are important in a complete theory of the physics of the earth; but the small yieldings of microscopic dimensions must be kept distinct from the great movements which have’ shaped the surface of the globe. Many of the small effects depend on the greater movements of the earth, while few of the great movements are influenced. by surface forces— indeed none at all, except where accumulation of subterranean stresses has already rendered the conditions highly unstable. In this latter case small surface forces may occasionally accelerate the outbreak of an earthquake, just as a spark discharges a loaded gun, or a shock explodes a charge of dynamite. On a par with the theory that slight inequalities of surface load- ing produce earthquakes is another equally untenable view that the earth is a failing structure. Such a doctrine might have been entertained a quarter of a century ago, when the theory of secular cooling was generally accepted, but to-day such a view is anti- quated and utterly indefensible. Owing to the demonstrated de- 258 SEE—FURTHER RESEARCHES ON [April 24, pendence of mountain making upon the sea the earth emphatically is not a failing structure. So far from failing by collapse, our planet seems to be expanding from Io to 100 faster than it con- tracts from loss of heat. Thus have arisen all the highest moun- tains and plateaus of the globe. These great uplifts invariably face the deepest oceans, from which the expulsion of lava has mainly proceeded. Such antiquated doctrines as that the earth is a fail- ing structure are now absolutely without excuse, and practically abandoned, and the sooner they disappear from scientific literature the better for sound knowledge of the physics of the earth. § 51. Changes of the Force of Gravity in Regions Affected by the Movement of Lava Beneath the Crust.—In view of the demon- strated movement of lava streams beneath the crust of the globe, it follows that such bodily displacement of matter but a short dis- tance below the surface may modify sensibly the observed intensity of gravity. A region which is being undermined will have the intensity of gravity decreased, and a region which is being filled up will have the attraction increased. And not only will the im- tensity vary, but also the direction of the vertical, according to the movements which occur beneath the crust. And these effects may be large enough to become sensible to very refined observation. It is in this way that the anomalies of gravity in the neigh- borhood of mountains have arisen in the process of mountain form- ation. And in regions where the expulsion of lava is still in progress, both the direction and intensity of gravity are subject to change by earthquakes. Thus in the region of the Aleutian Islands, the east coast of Japan, and many other places, such as the west coast of South America, the direction and intensity of gravity is cer- tainly subject to change by seismic disturbances. As the crust of the globe often suffers horizontal and vertical movement during the greatest earthquakes, the altitude and azimuth of places are also subject to change; and exact geodetic triangula- tion remains valid only for the interval between great earthquakes. Even then there may be a very slow and gradual settlement owing to plastic yielding of the crust and especially of the substratum beneath. Thus after earthquakes such as occur in Peru and Chili, Japan and Alaska, gravity and geodetic determinations need repeti- 1908.] THE PHYSICS OF THE EARTH. 259 tion, as was done in California after the great earthquake of April 18, 1906. And as the disturbance may alter the direction and in- tensity of local gravity, this possibility must be taken account of in the repetition of the observations. In order to be entirely rigor- ous the equations connecting the triangulation should include unde- termined multipliers to take account of possible variations in the local attraction at each point. If with this general condition im- posed, the triangulation before and after the earthquake comes out rigorously the same, within the limits of errors of observation, it may be supposed that the surface effects of the disturbance are insen- sible; otherwise the difference must be attributed to disturbances due to the earthquake. With the refinement now possible in geodesy, it is not to be doubted that these effects will occasionally prove to be sensible to observation. The great earthquake in Assam-Bengal gave rise to horizontal movements of the order of 20 or 30 feet, which may affect the latitude by 0”.2 or 0”.3, and are thus within the limits of astronomical measurement. But apparent changes in latitude may result from change in the direction of gravity as well as from actual displacements of the crust, and both possibilities need to be taken into account. § 52. The Necessity of Further Study of the Contours and Movements of the Sea Bottom.—In view of the results brought out in this paper and those which have preceded it, but especially that on “ The New Theory ot Earthquakes and Mountain Formation as Illustrated by Processes now at Work in the Depths of the Sea,” it is scargely necessary to point out the extreme importance of further study of the contours and movements of the sea bottom. Our present maps of the ocean depths are very incomplete, although they afford a good general idea of the sea basins. But one can scarcely doubt that more exact surveys would bring to light addi- tional mountain ranges and plateaus in regions heretofore but slightly explored; moreover certain places in the sea bottom would be found to be covered with a great variety of peaks or submerged islands which do not reach the surface. Where the water is deep the exact survey of the bottom pre- sents considerable difficulty. As movements arising from earth- 260 SEE—FURTHER RESEARCHES ON [April 24, quakes are extremely small in comparison with the depth of the sea, it would perhaps be very difficult to detect resulting changes of the sea bottom, except in cases where sinking takes place, and the drop is large. In some cases of actual measurement in the laying of cables the sinking has been found to be hundreds of fathoms, which would be very easily recognized if the exact place of former soundings could be found. But as the changes of level in the sea bottom are fully as capricious as on land, we see that regions where mountain formation is in progress would present extreme complexity; and unless the place were very accurately known, one could not be sure that two soundings were over the same spot. This difficulty would be less near known islands than in the open sea, but it would be considerable in all places where the ship is at the mercy of the winds and currents. Under the circumstances it is clear that great natural difficulty would arise in the exact Hydrographic survey of the deep sea, and an economic difficulty would be added, on the ground that such surveys are not required in practical navigation. Yet the laying and repair of cables would necessitate fairly accurate knowledge of the depths, and we may hope, in spite of the growth of the wire- less telegraph, that our ocean surveys are still in the infancy of what they will be in another half century. Where trenches are being dug out by earthquakes there will be the double incentive to ascertain the stage of the process and the rapidity and location of the changes. These considerations may contribute to our knowledge of particular regions; and, after all, the changes in the larger regions of the ocean bottom are small. When the regions in which trenches are forming are once clearly recognized, attention will naturally be centered upon them, to the neglect of less disturbed areas. The most interesting rfe- gions, from a seismological point of view, are those in which islands are being uplifted and the sea bottom sinking, as near the Aleutian, Kurile and Japanese islands, the Antandes, and along the west coast of South America. But it may also be hoped that the changes in depth near individual islands, such as Guam and Martinique, will not be overlooked. Here the subsidence of the bottom often takes the form of a hole rather than of a trench. Yet 1908.] THE PHYSICS OF THE EARTH. 261 in time the movements may give rise to neighboring islands. All of these considerations show the value of accurate knowledge of the sea bottom at this epoch. § 53. Greatness of the Forces which Uplift and fold the Earth’s Crust.—The tremendous power of earthquake and volcanic forces has been proverbial from the earliest ages of history, and finds expression also in the universal terror thus excited among all liv- ing beings. This extreme terror is only too well justified by the vast extent of the ruin too often wrought in different parts of the world. But probably only those who have witnessed a great earth- quake can adequately appreciate the awful character of the com- motion, and the gigantic forces which must underly it. This is shown also by the many published attempts to belittle the signifi- cance of earthquake disasters. Some writers of eminent mathematical learning, but apparently lacking in grasp of the larger physical phenomena, have ascribed earthquakes to inequalities of loading, changes of barometric pres- sure, etc., and have with strange and almost marvelous credulity believed that the settlements of the earth thus arising would shake down cities and devastate whole countries. How these learned authorities imagined that small subsidences under the steady action of these infinitesimal forces could bring about such long con- tinued shaking and proportionately great havoc is difficult to un- derstand. -If the forces are so small, and act so slowly, is it conceivable that the yielding could be anything else than gradual and insensible? Such minute settlements evidently would be like - those now experienced in dry inland regions free from real earth- quakes. The titanic nature of’ the forces which have uplifted islands, mountains, plateaus and continents, can scarcely be realized; yet even the ancients grasped it to some extent when they described the whole region between Naples and Sicily as underlaid by a giant, whose movements disturbed the intervening sea bottom. In his account of the Chilean earthquake of 1835, Charles Darwin showed that the entire region from the island of San Fernandez to the Andes, about 450 miles across, had been moved together by under- lying forces. “ There was undoubtedly a connection between the 262 SEE—FURTHER RESEARCHES ON [April 24, volcanic forces acting under this island, and under the continent, as was shown during the earthquake of 1835,” says the great naturalist. As such views have been carefully set forth by the greatest of original investigators, from Aristotle to Darwin, it is remarkable to witness the puny efforts which have been made to belittle these forces. A gentleman holding a university position, in a public address at Boston, recently likened the shock of an earthquake to the jar experienced by an insect attached to a reed which was bent till it snapped. According to this authority the earthquakes are due to the snapping of the rock of the earth’s crust in the bending produced by secular cooling. Is it necessary to point out the mis- leading character of the comparison made, and this lecturer’s utter inability to grasp the phenomena of nature? An equally common fallacy is to ascribe these tremendous dis- turbances to inequalities of surface loading, due to geological and meterological causes. Such views seem the more surprising, be- cause formerly they have proceeded from physicists of eminent learning. But at least partial excuse may be found in the universal acceptance of the theory of secular cooling heretofore, and in the proved rigidity of the globe, which naturally led to the supposition that the crust was adjusting itself to the shrinking sphere. Before the development of the theory of ocean leakage no ade- quate theory presented itself to investigators, who had unfortu- nately not discriminated between the great and small earthquakes. With a false premise and such an indiscriminate mixture of phe- nomena, real progress was difficult, if not impossible. § 54. Darwin's Remarks on the Forces which Uplift Continents. —In the extract quoted from Professor Suess, § 39, allusion has already been made to Charles Darwin’s attempt to explain the origin of mountains by the direct observation of nature. His paper “ On the Connection of Certain Volcanic Phenomena in South America and the Formation of Mountain Chains and Volcanoes as the Effect of the Same Power by which Continents are Elevated” (Transac- tions of the Geological Society, Vol. V, 1838, pp. 601-631) led Darwin to the conclusion: “That the form of the fluid surface of the nucleus of. the earth is sub- ject to some change, the cause of which is entirely unknown and the effect of which is slow, intermittent, but irresistible.” { 1908. ] THE PHYSICS OF THE EARTH. 263 Again, in the “ Voyage of the Naturalist,’ Chapter XIV, he adds: “The forces which iowly and by little starts uplift continents, and those which at successive periods pour forth volcanic matter from open orifices, are identical.” It is unnecessary to dwell on the irresistible power which the great naturalist correctly abscribed to volcanic and earthquake forces. It is of more interest to notice that he declared them to be identical with those which uplift continents. The same result is reached in the present paper, about three quarters of a century later, and the proof of the proposition now seems overwhelming. If Darwin had known the cause of seismic sea waves, and had seen how trenches are dug out in the sea bottom by the expulsion of lava from beneath the sea under the land, can anyone doubt that he would have discovered and proved the leakage of the oceans, and developed the correct theory of mountain formation? § 55. On the Oscillatory Movements of the Crust Shown in the Coal Measures.—In view of the results established in this paper we need not dwell on the coal measures, and other evidences of the oscillation of the earth’s crust. It suffices to say that these oscilla- tions actually took place, as geologists have long believed. The coal fields in Pennsylvania were formed by vegetation growing rapidly and with great luxuriance over areas near the sea level which were again and again elevated and as often depressed by earthquakes. When the land was under the sea the vegetation died out, and mud and shale were deposited; when the area was again upraised another layer of vegetation was produced, and sometimes it was deposited by floods, currents, and drifting where it had not grown. This was during the Carboniferous Age, and while all the land was near the level of the ocean. The details of such inquiries must be left to geologists and paleontologists, who study the flora and fauna of past ages. Our aim in these papers has been to give a firm basis for legitimate study and speculation, without which the phenomena of nature remain unintelligible. The progress of the sciences of the earth requires two conditions: first, true physical causes; and second, the intelli- gent and consistent application of these causes to the explanation 264 SEE—FURTHER RESEARCHES ON [April 24, of the phenomena, both of the animate and inanimate world. The physicist must content himself with showing the mechanical causes at work and their mode of operation, while the geologist and paleon- tologist may deal with the evidences of life under these known conditions. § 56. The Equilibrium of the Earth between the Land and Water Hemispheres Explained by the Intumescence of the Land Arising from the Expulsion of Porous Lava from under the Bed of the Sea. —The remarkable equilibrium preserved by the earth between the land and water hemispheres has long been a matter of speculation among philosophers. Sir John Herschel justly remarked that the high altitude of the continents in the land hemisphere would be most easily accounted for by an intumescence of the land. Pratt has since treated the question in a convincing manner, and shown that the solid parts of the earth’s crust beneath the water hemisphere, with pole in New Zealand, must be denser than in the correspond- ing parts on the opposite side, otherwise the water would flow away towards the land hemisphere and tend to submerge it more com- pletely. (Cf. “Figure of the Earth,’ 3d edition, pp. 159-160.) Hence he concludes that “There must therefore be some excess of matter in the solid parts of the earth between the Pacific ocean, and the earth’s center which retains the water in its place.” When Pratt wrote this forty years ago there was no suspicion of an intumescent layer beneath the land due to the expulsion of porous lava from beneath the bed of. the sea, and accordingly he added that “This effect may be produced in an infinite variety of ways; and therefore, without data, it is useless to speculate regarding the arrangement of matter which actually exists in the solid parts below.” Now, however, it is proved that the plateaus and continents have been uplifted by intumescent matter expelled from under the sea; and consequently we have data for speculating on how the observed effect is produced. It is clear that all the great plateaus of the globe and even the continents themselves are underlaid by material lighter than the average of the earth’s crust. Naturally the effects are greatest 1908. ] THE PHYSICS OF THE EARTH. 265 where the plateaus are highest, as in Himalayas and Tibet, where the deficiency in the attraction of these elevated masses long ago attracted attention. In his “ Account of the Operations of the Great Trigonometric Survey of India,’ Calcutta, 1879, .General J. T. Walker says: “There appears to be no escape form the conclusion that there is a more or less marked negative variation of gravity over the whole of the Indian continent, and that the magnitude of this variation is somehow con- nected with the height. “Pratt’s calculations had reference only to the visible mountain and oceanic masses and their attractive influences—the former positive, the latter negative—in a horizontal direction; he had no data for investigating the density of the crust of the earth below either the mountains on the one hand, or the bed of ocean on the other. The pendulum observations fur- nished the first direct measures of the vertical forces of gravity in different localities which were obtained, and these measures revealed two broad facts regarding the disposition of the invisible matter below; first, that the force of gravity diminishes as the mountains are approached, and is very much less on the summit of the highly elevated Himalayan table-lands than can be accounted for otherwise than by a deficiency of matter below; secondly, that it increases as the ocean is approached, and is greater on islands than can be accounted for otherwise than by an excess of matter below. As- suming gravity to be normal (in amount) on coast lines, the mean observed increase at the islands stations was such as to cause a seconds’ pendulum to gain three seconds daily, and the mean observed decrease in the interior of the continent would have caused the pendulum to lose 2% seconds daily at stations averaging 1,200 feet above the sea level, 5 seconds at 3,800 feet, and about 22 seconds at 15,400 feet—the highest elevation reached— in excess of the normal loss of rate due to the height above the sea.” The facts here mentioned by General Walker are recognized in geodesy as applying in different degrees to all the elevated table- lands and mountainous regions of the globe. The physical cause of this deficiency in attraction is now established beyond all doubt, and the intumescence of the land, first suggested by Sir John Herschel, is shown to have arisen from the expulsion of lava from beneath the sea. Thus arises .the physical condition which secures the equilibrium of the earth between the land and water hemispheres. This must be regarded as not the least remarkable among several interesting results on the physics of the earth deduced from the principle of the secular leakage of the oceans. Earth- quakes, volcanoes, mountain formation, the uplift of islands, plat- [April 24, SEE—FURTHER RESEARCHES ON 266 “aqops ay} Jo os9ydstway purl oy} Sunjziydn ur suvsdo dy} Jo UOTE Iv[NdIS dy} 0} SSOUIM BurysepIIAd uv se spueys d8prRy PpTJOAA 94} pue ‘A109, MAN 9} FO YINIZ 9Y} 0} AuOUTI}sa} aAISsoIduT siv9aq a10Jai9y} dew siyy ‘asoyds “Way J9JeM OY} SPIVMO} ST YOIYyM ‘QpIsnNO 9Y} 9dVJ IIaYMAIIAD sneoyed years pue sureyuNOW YSIY sy} Jey} posod1jOU 9q [][IM I] (‘sa9yst[qng “OD ® uur jo uorsstused Aq ‘Aydei80ar) ajofduiog = sPAIF WO) ‘asphky pyJoM ey} Surmoys deypy - ‘Si ‘oy 1908. | THE PHYSICS OF THE EARTH. 267 eaus, and continents, seismic sea waves, trenches and holes in the bottom of the sea, the feeble attraction of mountains, and plateaus, the equilibrium of the globe between the land and water hemispheres, are all closely related and dependent upon a single physical cause. Fic. 16. Water Hemisphere, which has the World Ridge around it, drawn by W. R. Smith, of Mare Island. In view of the order and harmony thus established among these varied phenomena, who will not concur in the view of the great Newton that “ Nature is pleased with simplicity and affects not the pomp of superfluous causes”? 268 SEE—FURTHER RESEARCHES ON [April 24, CONCLUSIONS. Some of the chief conclusions reached in this and the preceding papers on the physics of the earth may be briefly summarized as follows: 1. The theory of the secular leakage of the oceans explains satis- factorily six great classes of phenomena, not heretofore closely asso- ciated, namely: (1) Earthquakes, (2) volcanoes, (3)+mountain for- mation, (4) the formation of islands, plateaus and continents, (5) seismic sea waves, (6) the feeble attraction of mountains and plateaus long noticed in geodesy. 2. And the theory not only explains the leading facts of each class of phenomena separately, but also in relation to all the other classes of phenomena; and this harmonious mutual relationship of all the phenomena proves the theory to rest on a true physical cause. 3. A vera causa, once established, should not only explain all the phenomena, and all the relations, but also exclude the considera- tion of other possible causes, by necessary and sufficient conditions. This alone ensures the entire validity of the reasoning, and the pres- ent theory meets this severe test perfectly. 4. We have traced the details of the processes involved in moun- tain formation, and have exhibited illustrations of its working by processes now observed in the depths of the sea. All stages of mountain formation are thus brought out, and they are all shown to be consistent with this simple theory, which explains the princi- pal phenomena of the earth’s crust. é 5. This theory explains the distribution of mountains about the continents, their great height which the contraction theory cannot account for; the formation of parallel ridges by the uplift of the side of the trough nearest the sea, when the bottom has so far sub- sided that the folding up of the nearer side becomes the path of least resistance in the expulsion of molten rocks from under the sea. 6. Several successive troughs are often thus dug out, with ridges forced up between them; and when the whole is raised above the water we have a series of parallel ranges, such as the Allegheny, Tuscarora and Blue Ridge Mountains in Pennsylvania and Vir- 7 1908. ] THE PHYSICS OF THE EARTH. 269 ginia. Heretofore these vast billows of the earth’s crust have been utterly bewildering to the naturalist. 7. When several such trenches have been dug out, and the ex- pulsion of lava is from both sides, as happens when the sea is thus distributed, the ridges may finally be forced up and so crowded together from both sides that overturned dips and inverted strata are produced, as in the Swiss Alps. No previous theory has been adequate to account for this amazing phenomenon, the explanation of which is thus seen to be exceedingly simple. This test may be justly considered the experimentwm crucis of the theories of moun- tain formation. 8. The Andes in South America are nothing but a vast wall or embankment erected by the Pacific Ocean, through the expulsion of lava, along its border. Hence the persistence of the earthquake belt and seismic sea waves along this coast. g. This embankment includes not only the peaks and chains of mountains, large and small, in the Eastern and Western Cordillera, but also the intervening plateaus, such as those of Quito, Caxa- marca, Cuzco, and Titicaca. 10. The molten rock expelled from under the sea is lighter than average material of the layer below the earth’s crust, and when the included vapor of steam is allowed to expand, as in volcanoes, pumice is formed, and often blow out in vast quantities. Pumice of various degrees of density underlies the mountain chains, and some of it is blown out of those mountains which become volcanoes. 11. The way in which these plateaus are interwoven with the Andes mountains shows that the whole embankment is due to the continued action of one common cause. And since the mountains were uplifted by the expulsion of lava from under the sea, as proved by the uplifting of the land in earthquakes and the sinking of the - sea bottom, indicated by the accompanying seismic sea waves, it follows that the plateaus also are underlaid by matter lighter than the average, which has been expelled from under the ocean. 12. The total quantity of matter thus expelled from beneath the ocean is very large, but it is the result of an infinite number of earthquakes and seismic sea waves during past geological ages. This circumstance affords us an idea of the immense age of the PROC. AMER. PHIL. SOC,, XLVII. 189 R, PRINTED SEPTEMBER 25, 1908. =- 270 SEE—FURTHER RESEARCHES ON [April 24, Andes Mountains, which are the youngest of the great mountain systems of the globe. . 13. The terrible fracturing of the crust in the sharp folding involved in the formation of the Andes enabled a vast number of volcanoes to break out, and about one hundred and five have been active within historical times. 14. The formation and activity of the volcanoes in the Aleutian and Japanese Islands is similar to those in the Andes, and represent conditions suitable to the maximum development of volcanic activ- ity. These are sharp folds of the crust near a deep sea from which the expulsion of lava is rapid and violent. 15. The connection of earthquakes with. volcanoes and of both phenomena with the sea is clearly established by the geographical distribution and by the vapor of steam emitted by volcanoes. The nature of the underlying material is shown by the ashes, cinders, pumice and lava forced out by the accumulating subterranean steam pressure. : 16. Earthquakes, however, are the more general, volcanoes the more special phenomena. The mountains are formed by the sea, but only a few of the peaks break out into volcanoes. No volcano long remains active very far from the ocean or other large body of water, because as the lava hardens in the throat of the volcano the supply of steam is inadequate to maintain activity. 17. If we consider the innumerable islands in the sea, it is evi- dent that they too have been uplifted by earthquakes. Sometimes the sea bottom near them has been undermined in the process of uplifting, and afterwards sunk down, making an adjacent hole in the bottom, and producing seismic sea waves of the first class, as in mountain formation where trenches are being dug out near the continents. 18. Seismic sea waves of the second class are produced by the uplift of the sea bottom, into ridges, or submarine plateaus and islands. In such cases the water rises suddenly without previously withdrawing from the shore. 19. But seismic sea waves of the first class due to the sinking of the sea bottom, after it is undermined by the expulsion of lava, are the most important and most celebrated. The waves at Helike, 1908. ] THE PHYSICS OF THE EARTH. 271 373 B. C.; Callao, 1746; Lisbon, 1755; Arica, 1868; Iquique, 1877; Japan, 1896, were all of this class. 20. We may pass directly from the Andes to the Himalayas, and from the high plateaus of South America to those of Asia. Just as the plateaus from Quito to Titicaca were formed by the ,expul- sion of matter from under the Pacific, so also those of Tibet and Iran are due mainly to the expulsion of lava from beneath the Indian and Pacific Oceans. 21. In the case of the plateau of Tibet the resulting uplift is partly due to the combined action of the Pacific, which thus folded the ranges to the East. With two oceans so large and deep as the Indian and Pacific codperating in this uplift, it is no wonder that the maximum effect was produced and that Tibet became the highest plateau in the world. 22. The Himalayas are higher and further from the sea than the Andes, but the earthquake belt at the base still persists in both cases, and the configuration in regard to the sea shows that the causes at work to produce these mighty uplifts were absolutely similar. And if the mountains are due to the same cause, the plateaus are also. 23. The total height of Tibet is only about one sixth or seventh of the thickness of the earth’s crust, and hence the uplift, great as it is, is not such as would necessarily produce great volcanic out- breaks at the surface. 24. Great lava flows, however, occurred in India, and some vol- canic phenomenon are known in the Himalayas, but our knowledge of these mountains is not yet adequate to enable one to estimate just how much volcanic activity developed there. 25. Great lava flows are due to the rupture of the crust, by the opening of a fault near the sea, not to volcanic outbreaks. These flows are seen in Utah, Oregon and India, on a scale commensurate with the forces which have uplifted the mountains and plateaus. 26. One may pass directly from the mountains and plateaus of South America to those of Asia, and then to those on the Pacific slope of North America, by the most gradual stages. 27. In this transition the processes are so similar and the dif- ferences so small, that it is impossible to deny that the mountains 272 SEE—FURTHER RESEARCHES ON [April 24, and plateaus west of the Rocky Mountains were all formed through the uplift of the land by the Pacific Ocean. 28. The North American Plateau is larger, but correspondingly lower than those in Asia, so that the volume of material involved in the two uplifts is comparable. Thus all the great plateaus of the globe are due to the action of the sea, in the course of immeas- urable ages. The slowness of the process conveys the best con- ception of the vast interval of time since the consolidation of the globe. 29. Charles Darwin long ago held that “the forces which slowly and by little starts uplift continents and those which at successive periods pour forth volcanic matter from open orifices are identical.” He showed that the southern end of South America has recently risen from the sea, and Professor Suess has shown that the univer- sal lowering of the strand line throughout the principal countries gives a similar indication for all the lands of the globe. 30. If one end of a continent can be raised by earthquake forces depending on the sea, then obviously a whole continent can be raised by these forces ;'and similar uplifts can occur for all the continents in both hemispheres. The vast vertical walls of granite so often found rising from the sea in South America and elsewhere have clearly been uplifted by earthquakes. 31. We therefore reach the conclusion that the forces which have raised the mountains, islands and plateaus, have also raised the continents and established the equilibrium of the globe between the land and water hemispheres. This force is nothing else than common steam, operating through the expansion of molten rock be- neath the crust and arises principally from the secular leakage of the ocean bottoms. 32. The main effect of earthquakes is the production of more land. The continents are being lifted out of the sea, in spite of erosion, as we see by the withdrawal of the oceans to a greater and greater distance from old mountain chains, such as the Rocky Mountains and Appalachians in America and the Alps in Europe. 33. But for this uplift of the land by the leakage of the oceans none of the higher forms of life could have developed upon the earth. The climate and drainage of all continents have been largely 1908. | THE PHYSICS OF THE EARTH. 273 determined by these forces, which have produced the mountains and river systems of the world. 34. We cannot prove by experiments on rock twenty miles thick that it will leak under the pressure of the ocean, but we can observe the surface movements in earthquakes such as occur in Alaska, where lava is being expelled from under the ocean and pushed under the land. 35. This movement is everywhere in the same direction, whether in Alaska, Japan, the Antandes, South America, or elsewhere— namely from the ocean towards the land. The reason of this is that much steam is formed under the oceans, but scarcely any under the land, and hence it pushes up the crust along the edge of the con- tinents and finally almost walls them in with mountains, as was long ago pointed out by Dana. » 36. The old theory of secular cooling and contraction of the globe is false and misleading, and all who have carefully examined it agree that it is totally inadequate to account for terrestrial phenomena. In fact so far from contracting it seems certain that the earth is actually undergoing a slow secular expansion. 37. The Rev. O. Fisher and Major Dutton were among the earliest to reject this theory as incapable of explaining mountain ranges. But it is remarkable that after the contraction theory was proved to be unsatisfactory, it continued to be used in all works on geology and kindred sciences, and indeed still is accepted by those who adhere to the antiquated doctrine that the earth is a failing structure. Such views had some justification a quarter of a century ago; today they are absolutely without excuse. 38. There are the best grounds for accepting the doctrine of Isostacy, as approximately true for the earth at all times; conse- quently there are no sensible stress-differences, or tendencies to flow, except in the layers just beneath the crust. At greater depths the matter of the earth is made solid by pressure, being at the centre about three times more rigid than nickel steel. Hence deep down the earth is now and always has been quiescent. The only layer of the earth which is plastic and perhaps viscous is that just beneath the crust; this layer flows under the tremendous forces at work in earthquake movements. It is the movement of this molten rock be- 274 SEE—FURTHER RESEARCHES ON [April 24, neath the crust, chiefly when it is expelled from under the sea, which shakes down cities and devastates whole countries. | 39. This expulsion of lava under the land can mean nothing else than the secular leakage of the oceans, because the mountains along the coast which are rent by the shaking of the earth till they break into volcanoes, emit chiefly vapor of steam. Moreover the unsym- metrical shape of the mountain folds, showing the gentler slope towards the shore, indicates that the folds of the crust were pushed from the direction of the sea. This was produced by the expulsion of lava under the crust arising from the secular leakage of the ocean bottom. 40. By the study of seismic and other phenomena now observed in the great laboratory of nature we may penetrate the deepest secrets hidden beneath the earth’s crust, to which no mortal eye can ever bear direct witness. And these researches may greatly increase the safety of whole communities, and especially of cities and of commerce, throughout the world, by enabling us to guard against the dangers of earthquakes and seismic sea waves. This appro- priate use of the laboratory of Nature is one of the ultimate objects of natural philosophy. BLuE RipcE on LoutTRrE, MontcoMeEry City, Missouri, February 19, 1908. PoOotoCRIPT: In a paper read before the Royal Society in 1902, Professor J. H. Jeans, formerly of Cambridge, now of Princeton University, has the following theory of earthquakes: “Tt seems to be almost certain that the present elastic constants of the earth are such that a state of symmetrical symmetry would be one of stable equilibrium. On the other hand, if we look backward through the history of our planet, we probably come to a time when the rigidity was so much that the stable configuration of equilibriums would be unsymmetrical. At this time the earth would be pear-shaped and the transition to the present approximately spherical form would take place through a series of ruptures. It is suggested that the earth, in spite of this series of ruptures, still retains traces of a pear-shaped configuration. Such a configuration should possess a single axis of symmetry, and this, it is suggested, is an axis which meets the earth’s surface somewhere in the neighbourhood of England (or pos- sibly some hundreds of miles to the southwest of England). Starting from 1908.] THE PHYSICS OF THE EARTH. 275 England we find that England is at the centre of a hemisphere which is practically all land; this would be the blunt end of our pear. Bounding the hemisphere we have a great circle, of which England is the pole, and it is over this circle that earthquakes and volcanoes are of most frequent occurrence. Now, if we suppose otir pear contracting to a spherical shape, we notice that it would probably be in the neighbourhood of its equator that the changes in curvature and the relative displacements would be greatest, and hence we would expect to find earthquakes and volcanoes in greatest number near this circle. Passing still further from England, we come to a great region of deep seas, the Pacific, South Atlantic, and Indian Oceans; these may mark the place where the ‘ waist’ of the pear occurred. Lastly we come almost to the antipodes of England, to the Australian conti- nent. This may mark the remains of the stalk-end of the pear.” (Nature, Vol. LXVII., p. 190.) _ After what has been shown in this series of papers, it is un- necessary to dwell upon this hypothesis of Professor Jeans, which has the merit of originality; but we may remark that if it gave a true view of the physics of the earth, there should be a belt around the globe of at least the width of the terrestrial radius, over which the earthquakes are about equally distributed, whereas in fact they are felt principally along the margins of the Pacific Ocean. The observed earthquake belt on land is so narrow that it is clearly impossible to ascribe the effects to this supposed adjust- ment of the earth’s figure. And of course it fails totally to ac- count for the sinking of the sea bottom and the uplift of the coast, which is typical of mountain formation. THE ABSORPTION SPECTRA OF NEODYMIUM CHLO- RIDE AND PRASEODYMIUM CHLORIDE IN WATER, METHYL ALCOHOL, ETHYL ALCOHOL AND MIXTURES OF THESE SOLVENTS. (With six plates.) TWENTY-FIRST COMMUNICATION. By HARRY C. JONES anp JOHN A. ANDERSON. (Read April 25, 1908.) (This is a preliminary report on part of an investigation carried out with the aid of a Grant from the Carnegie Institution of Washington.) The absorption spectra of salts of cobalt, nickel, copper, iron, ~ chromium, neodymium, praseodymium and erbium have been stud- ied in the present investigation. Of these the salts of neodymium and praseodymium are perhaps the most interesting and important. This is due to the large number of absorption bands shown by these substances, and, further, to the very unusually sharp character of these bands. The method employed in making the spectrograms consists in allowing light from a spark, or from a Nernst filament, to pass through the solution in question, fall upon a grating and then upon the photographic plate. For visual work a small direct vision grating pocket spectroscope was found very convenient and useful. For photographing the spectra the vertical grating spectroscope used by Jones and Uhler* was employed. In making the photographs the Seed L-ortho film was used for the region from A 2000 to about A 6000. For photographing the red end of the spectrum a Wratten and Wainwright panchromatic glass plate was used. *Carnegie Publication No. 60. 276 1908.] NEODYMIUM AND PRASEODYMIUM. 277 ~ The Nernst filament was found to be the most satisfactory source of light from the extreme red to the beginning of the ultra- violet. It is sufficiently brilliant to require an exposure of only a minute, but practically ceases at about 43200. For wave-lengths shorter than this some spark spectrum must be used. The cadmium-zine spark used by Jones and Uhler was fairly satisfactory, especially in the extreme ultra-violet, but has the draw- back that there are present a limited number of very intense lines, on a rather faint continuous background. We tried to obtain a spark spectrum having a very large number of lines, but with no lines of very great intensity. We found that tungsten, molybdenum and uranium all satisfied these requirements. The terminals finally used were prepared by dipping pieces of carbon in a concentrated solution of ammonium molybdate, and ‘then heating in a bunsen burner. They were then dipped into a solution of uranium nitrate and similarly heated. The coil used to produce the spark was a large R6ntgen X-ray coil. MAKING A SPECTROGRAM. In making a spectrogram consisting of seven photographic strips, the following-mode of procedure was adopted: Seven separate solu- tions were made up of the desired strengths. The cell? to be used was filled to the required depth with the most concentrated solution of the series, and the quartz plates determining the depth of the solution adjusted to parallelism. The exposure to the Nernst lamp was then made, being usually one minute long. An opaque screen covering up the visible spectrum as far down as X 4000 was then interposed between the grating and the photographic film, and the exposure to the light of the spark in the ultra-violet made. The duration of this exposure was usually about two minutes. The photographic film was then moved into the proper position for the next exposure. The above series of operations was then repeated for each of the succeeding strips. After the film had been exposed for each solution and the spark spectrum impressed, it was necessary to make a similar series of * See Carnegie Publication No. 60. 278 JONES AND ANDERSON—ABSORPTION SPECTRA OF [aprilas. exposures on a panchromatic plate for the red end of the spectrum, using the same set of solutions. | The scale accompanying the spectrograms was made by photo- graphing an ordinary paper scale. Several photographs were taken, the distance between the paper scale and the lens of the camera being varied slightly from exposure to exposure. The resulting negative which fitted the majority of spectrograms best was selected and used throughout. NEODYMIUM CHLORIDE IN WATER—BEER’s LAw. (See plate 1.) The concentrations of the solutions of neodymium chloride were so chosen and the depths of cell so selected that the total amount of coloring matter in the path of the beam of light was kept constant. From Beer’s Law the absorption shown by the several solutions, under these conditions, should be the same. The concentrations of the solutions used in making the negative for a, plate 1, beginning with the one whose spectrum is adjacent to the numbered scale, were 3.40, 3.02, 2.72, 2.38, 2.17, I.90 and 1.70; the corresponding depths of cell being 12, 13.5, 15, I7, 19, 21.5 and 24 mm. For B, plate 1, the concentrations were 3.40, 2.55, 1.70, 1.13, 0.80, 0.57 and 0.43; the corresponding depths of absorbing layer being 3, 4, 6, 9, 13, 18 and 24 mm. The most concentrated solutions appeared brownish yellow in their bottles, from which the color changed on dilution to a yellowish pink, the color being extremely faint in the most dilute solutions. The exposures to the light of the Nernst lamp and spark were, respectively, I minute and 2 minutes; the slit having a width of 0.01 cm. The exposures and slit width were not varied in the work recorded in the present chapter, the object being to make the spectro- grams as nearly comparable as possible. Both a and b of plate 1 show the presence of some general absorption in the ultra-violet, which decreases quite rapidly with dilution. The absorption bands also narrow somewhat with de- crease in concentration, especially from 3.4 normal to about 1.7 normal. For concentrations less than about 1.5 normal Beer’s Law seems to hold very accurately indeed, with the exception of the PROCEEDINGS AM. PHILOS. Soc. VoL. XLVII. No. 189 PLATE | te i 3840 424 j nas 1908. ] NEODYMIUM AND PRASEODYMIUM. 279 shading towards the red accompanying the band near A 5800, which seems to decrease somewhat with dilution for concentrations of one normal or less. In the following table the measurements of the positions of the bands were made on the seventh strips of a, plate 1, and, therefore, refer to a concentration of 1.7 normal with a depth of layer of 24 mm. The remarks referring to changes with dilution apply to a change in concentration from 3.4 to 1.7 normal, the depths of layer being so varied that the product of concentration and depth remains constant. A Character. Remarks. 2810 Faint transmission begins. 2890-2910 Band with well defined sharp edges. 2970-29905 = £194) feyoepeay = ‘uonsesip 6x S1-o- be ayeyd —_ ° _— — [R10], + mee -ul ‘vasneu ‘ uswopqe So’o “jus zaddos [230 pue yoeuojs ur sureg eur} (3431s — sa0eg (aarsnqouos | (248s | (S989 | (seseo “ysex pue vas un ia) am =: = jou) AJOA tk ok tea Be — | -neu saummeuos { sured Sz Z*O-1'0 Sr apAyapyeulio 7 resol | — [eo], - + " Pat? [eurmop qv ‘syoupeay (3431s) Qysys | (aq3ys + ses a soyeozuag (FEBS) | .:-0.0cceecen] sossccs asses ‘opny : —) ce) Sn + + 2 Gusis) -sse] ‘oysepeay “easneyy gst S*z-1 oz = nee = ploe s1ozueg (343ys |—se00q| — eury | (sadaj ur | (paxreur (peyzeu . + tsea) + + Ayjeadsa)| Aza) ae (a3Hs) | 4 —_ Softer | 794"0- ougd TeI0y, | jeIoy + — + we t *uorssaidep £zzo “ns ~~ unrpos (aq8ys |—se0a,q)— ourg | (se09j ur | (payreut (pexzeur iged“ucaiiasp scseres = + Ara) + a Ayperoadsa ) 5m +f (343118) |* S;0ur) ° : re 9S3°9 vo- ited rs reroy, | e107, ef ee + Ts 1Zr1°0 snoinydjns +oury + sung (+ Apmis] (Apnis *je19ues jou swioydurAs $93] = - _ = (3431s) + + | [ersads)| yetsedg) fc) — |‘ured jeurmopqe pue Sgof | z-1z'o of -Aoyes pue je10 J, — [e810] ° ° ‘ayoepeoy WSs ‘193un zy pre oyAoyes (jyeurs ° ° ° se: : € *$-S- £01 of Aroa) | 0 | seeerees + Aus + + aiueaslen “epaper PE: Lae 0°S-S'0 | of 010 poe on0g =f ° ° + _ ° — | ‘easneu ‘ajnodde jo ssoyT ¢*6L | 0°€-S'o | (sartas €) xelog : *suIvIS) poy “soIpog : . ‘suivig,| ‘sXe "sprog | “3eq 4 onoyd | ‘ueZonIn : aidoos | ‘AyIprloy ndtv “UNO A parma yunoury oe ‘aouRjsqng -soug saposndiog | -o101;q WYSIOM *S3ION [eI0_L Ajreq | s9quinyy poold peat Pog Teorey pus [eIpaw “u0IyaI0x [e190 - jo Spewenicksh “UIST[Og BIOL “SUONCUIMIIDJEq SUII-) "SPATJVAIOSIIG JO UOT}VI}SIUIMIPY ;SUALLVANASAUG AG GHONANTANT SV WSITOdVIa}Y INV HLIvap lad. 6 git UPON HEALTH AND METABOLISM. 309 and in addition to that a number of calculators were employed to tabulate, classify, and average the data. The experimental data which were obtained are published in Bureau of Chemistry Bulletin 84, which when completed will contain the entire series of studies. Part I, of Bulletin 84, is devoted to the detailed study of the effect of borates and boric acid upon health and metabolism. This part of the Bulletin consists of 477 pages. Part II is devoted to the study of salicylic acid and salicylates and contains’ 283 pages. Part III contains the data relating to sulphurous acid and sulphites, and contain 281 pages, making a total of published matter of 1,041 pages. 1908. ] CHANGES IN THE URINARY NITROGEN AND SULPHUR CompouNDs.* = sla] | slog les gee | g | 3/2) 8] 2 | eladle2 lei Preservative. 6 $A 5 eal ala I F 3 13a | ee | os Ads =) 2 ey 3 a © Re) of | ae i pi|M|/<| * | 4) &/ 8a Ra UNEAEES, vais doavavcecbis.+ PING aOR VIF a ski Gas |e bene ditevsesl coecedl so xvh o'deb| decors loceseeleveese lacsace EGG Dae eae OR rose vvasone lskocen serene) ines Revaceceatansake lecease leaseaetiessesing Salicylic acid and sali- ENE she nse psek cavers 0,.21-2.0 — |—/+/— ° +)+ti]/+ 4+ Sulphurous acid.........) 0.17-0.4 ‘ 6 \ +y+y+/+ Sulphites................. 0. 22-0.76 { Con Ages a yeh to Benzoic acid ............ Bender ae eee Pan dwaek vil ees on] Fontes tee sack [aaeue Bese —;+;+)]0 Benzoates. ........+... Veo raeaehoe, Gyr tess eu ancl? seas] veveog|soseaelsessea ety —/;+]+4+)]0 Formaldehyde........... 0.1 -0.2 Ta a lasncnal xsae~alnbs opebcoasaae xe Oo) 20s] O40 Copper sulphate........ 0.05-0.15 | — | + |...... jesse + };+})—|]o]— Potassium nitrate....... 0.15-0.6 — fo) Coed ae an MRE Ey —|oj}+)] 0 The data relating to benzoic acid and benzoates are in press. These data, together with those relating to the other parts of the study which have been completed and submitted for publication, will make a volume of approximately 2,100 pages. All that I can give in this paper will be the general conclusions relating to each part of the study. CONCLUSIONS. Boric Acid and Borates.——In the consideration of the action of preservatives of a mineral nature, such as borax and boric acid, it must be remembered that the animal as well as the plant possesses *Minus and plus signs indicate decreased or increased total excretion in preservative period as compared with the fore period. 310 WILEY—INFLUENCE OF PRESERVATIVES [April 25, a certain mineral hunger. In other words, mineral substances play a double role in animal and plant nutrition: First, they may serve as real foods, necessary to the formation and nutrition of the tissue. In the animal economy this is especially true of phosphoric acid and lime. In the second place, they are necessary to the func- tional activity of the various organs of the body, irrespective of any part they may take in direct nutrition. The necessity of saline solutions in the blood is known to every physician and physiologist. If the blood were deprived of all of its saline constituents the circulation would be impeded, restricted, or stopped, and death would result. In cases of collapse in disease saline injections in the blood are often used as a restorative measure. These salts in solution stimulate the heart’s action and undoubtedly are active in the osmotic operations of the cells. This is one of the facts which show the intimate relation existing between physical chemistry and physiology. Common salt is the most frequent and most abundant of the saline constituents of the blood, but the alkalinity of the blood is not due of course to the common salt, which is a neutral substance. The existence of alkaline carbonates or other alkaline salts is neces- sary to the vital functions. While it is true that the digestion in the stomach takes place in an acid solution, it is likewise true that any excessive acid must be neutralized and enough of alkali added in the small intestine in order that the further digestion of the food may properly take place. That saline bodies other than common salt or the alkaline carbonates may be useful, however, in the perform- ance of the vital functions cannot be denied, though it might be difficult to demonstrate their absolute necessity. Hence the intro- duction of saline bodies, which may or may not be of an antiseptic character, may, within certain limits, have a favorable influence upon health and digestion. At the same time it should not be forgotten that all excess of such bodies imposes upon the excretory organs an additional burden, which, while it might not impair their efficiency even for a number of years, might finally produce a condition of exhaustion which would be followed by serious consequences. Especially is this remark true of the kidneys, which appear to be a 1908.] UPON HEALTH AND METABOLISM. 311 general clearing house for all the surplus of saline matters, ingested in the foods. ; The most interesting of the observations which were made dur- ing the progress of the experiments was in the study of the direct effect of boric acid and borax, when administered in food, upon the health and digestion. When boric acid, or its equivalent in borax, is taken into the food in small quantities, not exceeding half a gram (74 grains) a day, no notable effects are immediately pro- duced. The medical symptoms of the cases, in long-continued ex- hibitions of small doses or in large doses extending over a shorter period, show in many instances a manifest tendency to diminish the appetite and to produce a feeling of fullness and uneasiness in the stomach, which in some cases results in nausea, with a very general tendency to produce a sense of fullness in the head, which is often . manifested as a dull and persistent headache. In addition to the uneasiness produced in the region of the stomach there appear in some instances sharp and well-located pains, which, however, are not persistent. Although the depression in the weight of the body and some of the other symptoms produced persist in the after periods, there is a uniform tendency manifested after the with- drawal of the preservative toward the removal of the unpleasant sensations in the stomach and head above mentioned. The administration of boric acid to the amount of 4 or 5 grams per day, or borax equivalent thereto continued for some time, results in most cases in loss of appetite and inability to perform work of any kind. In many cases the person becomes ill and unfit for duty. Four grams per day may be regarded, then, as the limit of exhibi- tion beyond which the normal man may not go. The administration of 3 grams per day produced the same symptoms in many cases, although it appeared that a majority of the men under observa- tion were able to take 3 grams a day for a somewhat protracted period and still perform their duties. They commonly felt injurious effects from the dose, however, and it is certain that the normal man _ could not long continue to receive 3 grams per day. In many cases the same results, though less marked, follow the administration of borax to the extent of 2 grams and even of I gram per day, although the illness following the administration of 312 WILEY—INFLUENCE OF PRESERVATIVES [April 2s, borax and boric acid in those proportions may be explained in some cases by other causes, chiefly grippe. The administration of borax and boric acid to the extent of one half gram per day yielded results markedly different from those obtained with larger quantities of the preservatives. This experi- ment, Series V, conducted as it was for a period of fifty days, was a rather severe test, and it appeared that in some instances a some- what unfavorable result attended it. On the whole, the results show that one half gram per day is too much for the normal man to receive regularly. On the other hand, it is evident that the normal man can receive one half gram per day of boric acid, or of borax expressed in terms of boric acid, for a limited period of time without much danger of impairment of health. It is, of course, not to be denied that both borax and boric acid are recognized as valuable remedies in medicine. There are certain diseases in which these remedies are regularly prescribed for both internal and external use. The value which they possess in these cases ddes not seem to have any relation to their use in the healthy organism except when properly prescribed as prophylactics. The fact that any remedy is useful in disease does not appear to logically warrant its use at any other time. It appears, therefore, that both boric acid and borax, when con- tinually administered in small doses for a long period or when given in large quantities for a short period, create disturbances of appe- tite, of digestion, and of health. Salicylic Acid and Salicylates.—In the conclusions based upon the general observations the same conservatism must be observed and the same general reservations made as are found in Part I concerning boric acid and borax. While, as described in the borax report, the attempt has been made to control as far as possible, all the conditions of the experimental work, the difficulties attending the task are so enormous that it is not possible that complete suc- cess should be secured. There has, however, been no attempt made to discriminate in the choice of data, all the observations being recorded and the discussion of the individual data based upon the tabular statements being without prejudice and without bias. The general assumption has been made, as in the previous cases, that, 1908. ] UPON HEALTH AND METABOLISM. 313 by reason of the regular habits of life which were imposed upon the subjects, the amount of energy developed and the quantity of nour- ishment expended therein are reasonably constant throughout the experimental period. If these factors vary, as they necessarily must to a certain degree, it is evident that they vary uniformly above or below the average, and hence these variations could not possibly produce any notable effect upon the final result. There has been a general consensus of opinion among scientific men, including the medical profession, that salicylic acid and its compounds are very harmful substances, and the prejudice against this particular form of preservative is perhaps greater than against any other material used for preserving foods. This is due not only to the belief in the injurious character of salicylic acid, but perhaps is especially due to the fact that it has in the past been so generally used as an antiseptic. That salicylic acid should be singled out especially for condemnation among preservatives does not seem to be justified by the data which are presented and discussed in this bulletin. That it is a harmful substance, however, seems to be well established by the data taken as a whole, but it appears to be a harm- ful substartce of less virulence than has been generally supposed. There is no doubt of the fact that salicylic acid is a drug which is often indicated in diseases well established and also perhaps in cer- tain conditions which, while verging on disease, might still be re- garded as a state of health. But the administration of salicylic acid as a medicine should be controlled exclusively by the medical pro- fession, and while it is a remedy well established in the Pharma- copeeia and especially prized for its effect upon rheumatism and gout, it does not seem that there should be any warrant in this fact for its promiscuous use in foods, even if it were harmless. The data show very clearly that salicylic acid and salicylates appear to exert an exciting influence upon the activities which take place in the alimentary canal, stimulating the organs to greater effort, and this stimulation leads at first to increased solubility and absorp- tion of the foods which are introduced into the stomach. In the light of the data which are exhibited salicylic acid may be said to increase the solubility and absorption of the food in the alimentary 314 WILEY--INFLUENCE OF PRESERVATIVES [April 25, canal, so that larger parts of the nutrients taken into the stomach actually enter the circulation. . The data which show the effect just noted also indicate that the general effect upon the system is depressing, in that the tissues are broken down more rapidly than they are built up, and thus the normal metabolic processes are interfered with in a harmful way. The administration of the salicylic acid is attended by a gradual decrease in the weight of the subjects, although the quantity of food elements administered during the preservative and after periods is slightly increased, which fact, together with the greater degree of absorption of the food elements, should have resulted in a slight increase in weight. This increase in weight, however, does not occur, and the disturbing influence of the salicylic acid upon meta- bolism, although not very great, is specifically demonstrated. The final conclusion in this matter, therefore, is that the un- enviable position which salicylic acid has heretofore held among preservatives, in being regarded as the most injurious of all, is to a certain extent undeserved. Like other ordinary preservatives, it is not one which can be classed as a poison in the usual sense of the word. When used as a medicine in many cases of derangement of health it is like the other chemical preservatives, often highly bene- ficial when properly prescribed by a competent physician. It is when used in the food at first an apparent stimulant, increasing the absorp- tion and solubility of the common food elements from the alimen- tary canal. It soon, however, loses its stimulating properties and becomes a depressant, tending to break down the tissues of the body more rapidly than they are built up. It disturbs the metabolic proc- esses, in most cases producing conditions which are not normal and which, apparently, are not beneficial. It has a tendency to diminish the weight of the body and to produce a feeling of discomfort and malaise, which, while not marked, is distinctly indicative of injury. In some cases these symptoms of malaise approach illness, and while not always diagnostic are sufficiently common to point unmistakably to the salicylic acid as their origin. It places upon the excretory organs, especially the kidneys, an additional burden which they are not able to bear and which cannot possibly result in any good, but on the contrary must necessarily finally result in injury, though per- 1908.] UPON HEALTH AND METABOLISM. 315 haps with the use of very small quantities of the preservative these organs would continue to perform their function for many years before finally breaking down. . This work is offered as an unbiased study of all the data re- corded, both of those whjch appear to be in favor of the use of salicylic acid and those which appear to be against its use, and leads to the inevitable conclusion that salicylic acid is a substance which, when added to foods even in small quantities, exerts a depressing and harmful influence upon the digestion and health and the general metabolic activities of the body. Further, there appears to be no necessity for its use, as food can be preserved in unobjectionable ways without its aid. Its indiscriminate use would tend to care- lessness in the quantities employed, thus increasing the dangers to which the consumer is subjected. Also its use in the preservation of foods tends to induce carelessness and indifference on the part of the manufacturer, as when a chemical antiseptic is employed many of the processes necessary to the proper selection, cleaning, and preservation of foods may be omitted. The addition of salicylic acid and salicylates to foods is there- fore a process which is reprehensible in every respect, and leads to injury to the consumer, which, though in many cases not easily measured, must finally be productive of great harm. Sulphurous Acid and Sulphites—From a careful consideration of the data in the individual cases and the summaries of the results, it appears that the administration of sulphurous acid in foods, either in the form of sulphurous acid gas in solution or in the form of sulphites, is objectionable and produces serious disturbances of the metabolic functions and injury to health and digestion. This injury manifests itself in a number of different ways, both in the produc- tion of clinical symptoms which indicate serious disturbances, malaise, or positive suffering, and also by inducing certain changes in the metabolic processes which are not manifested in the way of ordinary clinical symptoms, and are only detected by careful chem- ical and microscopical study of the excretory products. It can safely be said. from the evidence adduced that the administration of sodium sulphite and sulphurous acid as above indicated produces a marked influence of an unfavorable character on metabolism. As 316 WILEY—INFLUENCE OF PRESERVATIVES [April 25, a result of this action an assimilation of food materials containing organic phosphorus is retarded, while there is evidence of increased sulphue katabolism. The sulphur balance sheets show what an immense burden has been added to the already overworked kidneys, which are called upon in this case to remave nearly all, if not quite all, of the added sulphur from the body, previously converted, in great part to sulphuric acid. It is not possible that placing upon the kidneys this increased work of excreting sulphur can result in anything but injury. The fact that the microscopic crystalline and amorphous bodies in the urine are increased in number under the influence of the added sulphur, is another indication of the extra- ordinary demands made upon the kidneys in such circumstances. This increase is interesting in respect of the effect which the continued exhibition of sulphurous acid must eventually have upon the structure of the kidney. It is reasonable to suppose that the continued use of a body which produces such results would cause lesions of a histological character which eventually would develop conditions which would give serious apprehension. In the nature of these experiments it was not possible to examine the organs of the body histologically and hence the above conclusion is only based upon experience of a similar character where the organs in question have been subject to such examinations. While there might be no distinguishable lesion of the kidneys produced during a period of twenty or thirty days, or even longer, it is plain that sooner or later lesions of a very serious character producing organic diseases, pos- sibly of an incurable type, would be induced. The further observa- tion that there is a marked tendency to the production of albu- minuria, although of an incipient character, is an indication of the unfavorable results of the administration of the sulphurous acid. It is, therefore, evident that by increasing the burden upon the excretory organs, the administration of sulphur in the form men- tioned is highly detrimental to health. All of these tendencies cannot be interpreted as being other than of a decidedly harmful nature. Another effect which the adminis- tration of the sulphur produced, and one of a more serious character still, is found in the impoverishment of the blood in respect of the number of red and white corpuscles therein. The administration 1908.] UPON HEALTH AND METABOLISM. 317 of a substance which diminishes by a notable percentage these im- portant component particles of the blood must be regarded in every sense as highly prejudicial to health. Some of the most important functions of the blood, as has been well established by careful physiological studies, are intimately connected with the number and activity of both the red and white corpuscles. The bleaching effect of the sulphurous acid upon the color of the blood is a matter of less consequence and no great effect is produced upon the hemo- globin, but the diminution of the number of red and white cor- puscles is a matter of serious concern. The variations of the metabolic processes from the normal, as indicated in this series of experiments, were never of a character favorable to a more healthy condition of the system, but, on the other hand, all these variations, in so far as the effect of the changes could be distinguished, are of a prejudicial character. There is no evidence whatever that the sulphur added to the foods in the form of sulphurous acid, or sulphites, takes any part in the nutrition of the tissues of the body containing sulphur, namely, the proteids ; hence, no claim of food value can be established for these bodies. The evidence all points to the fact that they are purely drugs, devoid of food value, having no favorable effects upon the metabolic proc- esses, but, on the other hand, exerting deleterious and harmful effects. The conclusion, therefore, is inevitable that, as a whole, the changes produced in metabolic activity by the administration of sulphur in the forms noted above in the comparatively short time covered by the experiments are decidedly injurious. The verdict which must be pronounced in this case is decidedly unfayorable to the use of this preservative in any quantity or for any period of time, and shows the desirability of avoiding the addi- tion of any form of sulphurous acid to products intended for human food. Bengoic Acid and Benzoates.—From a careful study of the data in the individual cases and of the summaries of the results, it is evident that the administration of benzoic acid, either as such or in the form of benzoate of soda, is highly objectionable and pro- duces a very serious disturbance of the metabolic functions, attended with injury to digestion and health. . PROC, AMER. PHIL. SOC., XLVII. 189 U, PRINTED SEPTEMBER 26, 1908. 318 WILEY—INFLUENCE OF PRESERVATIVES tApitl ss: As in the case of boric acid, salicylic acid, and sulphurous acid, this injury manifests itself in a number of different ways, both in the production of unfavorable symptoms and in the disturbance of metabolism. These injurious effects are evident in the medical and clinical data which show grave disturbances of digestion, attended by phenomena which are clearly indicative of irritation, nausea, headache, and in a few cases vomiting. These symptoms were not only well marked, but they were produced upon healthy individuals receiving good and nourishing food and living under proper sani- tary conditions. It is only fair to conclude, therefore, that under similar conditions of administration of benzoic acid or benzoate of soda in the case of weaker systems, or less resistant conditions of health, much more serious and lasting injury would be produced. It was also noticed that the administration of benzoic acid and benzoate of soda was attended with a distinct loss of weight, indica- tive of either a disturbance of assimilation or an increased activity in those processes of the body which result in destruction of tissue. The production of a loss of weight in cases of this kind must be regarded as indicative of injurious effects. The influence of the benzoic acid and benzoate of soda upon metabolism was never of a character indicative of a favorable change therein. While often the metabolic changes were not strongly marked, such changes as were established were of an injurious nature. It is evident that the administration of these bodies, there- fore, in the food tends to ‘derange metabolism in an injurious way. An important fact in connection with the administration of these bodies is found in the efforts which nature makes to eliminate them from the system. In so far as possible the benzoic acid is converted into hippuric acid. There is a tendency usually manifested, how- ever, to retain the benzoic acid in the body for a notable length of time, and this is much more marked in the case of benzoate of soda than in the case of benzoic acid. While the administration of both these bodies, therefore, is undoubtedly harmful, the injurious effects are produced more rap- idly in the case of benzoic acid than they are in the case of benzoate of soda; the data, however, will show that the total harmful effect produced in the end is practically the same in both cases, hence there 1908] UPON HEALTH AND METABOLISM. 319 appears to be no reason for supposing that the administration of the preservative in the form of benzoate of soda can be justified by any argument relating to the less injurious effect thereof upon health. The occurrence of microscopic bodies in the urine is undoubt- edly increased under the administration of benzoic acid in all its forms, thus showing conclusively the tendency to stimulate the destructive activities of the body. Coming to the final consideration of all these different phases of the subject, there is only one conclusion to be drawn from the data which have been presented and that is that in the interests of health both benzoic acid and benzoate of soda should be excluded from food products. This conclusion is reached independently of any consideration of the conditions which it is alleged surround the processes of manufacture and which result in the demands of manu- facturers to be allowed to continue the use of this body. This is a subject which must be discussed from an entirely different point of view and has no bearing whatever upon the general conclusions which have been reached, namely, that both benzoic acid and ben- zoate of soda are bodies which, when added to foods, are injurious to health. Formaldehyde.—A general study of all the data leads to the conclusion that the admixture of formaldehyde with food is injuri- ous to health, even in the case of healthy young men. It is fair to conclude, therefore, that in the case of infants and children the deleterious effects would be more pronounced. The metabolic func- tions are disturbed in a notable way, both by the retardation of the nitrogen and sulphur metabolism, and the acceleration of phos- phorus metabolism. There seems to be a tendency to an increased absorption from the alimentary canal, especially in the cases when the formaldehyde had stood in contact with the milk, and hence it is fair to presume that in so far as the enzymic action in the intes- tinal canal is concerned, transforming solid food into soluble mate- rials which may enter the circulation, there is evidently a stimulat- ing effect produeed. There are, however, many varying conditions which must be considered in properly interpreting the data. The uniformly in- creased absorption of the proteid elements of the food, and also of 320 WILEY—INFLUENCE OF PRESERVATIVES [April 25, the sulphur and phosphoric acid, accompanied in the first two in- stances by a decrease in the metabolized elements excreted and in the last instance, namely, phosphoric acid, by a pronounced increase in metabolism, makes the explanation of the data rather difficult. Attention should be called to the fact that while the variations from normal metabolism are not very wide, the individual data are re- markably uniform and consistent. The conditions which are noted in the case of the proteins would lead one to expect a gain in the body weight. This expectation, however, is not realized for either class of subjects, although the losses in weight are so slight as to be practically negligible. The ratio of the food weight to the body weight was uniformly main- tained throughout the experiment, and, hence, if no variations in metabolic activity had occurred a fair presumption would have been that the body weight would remain constant. That the change of weight was slight in the view of the disturbances of the metabolic functions may be accounted for by the inhibiting or retarding influ- ence of the preservative upon the nitrogen and sulphur katabolism, or by the slight increase in water in the urine and feces. It cannot be maintained, however, that a retarded katabolism is beneficial to health. On the contrary a more rapid renewal of the tissues within the limits of healthy activity would be more likely to pre- serve a normal condition. The old tissues cannot be expected to functionate as perfectly as those which are newer, and hence, within reasonable limits, a change of the tissues of the body must be con- sidered as necessary to a healthy condition, and the maintenance of a normal vitality. The medical data indicate plainly that formaldehyde, even when — given in small quantities, is an irritating substance to the mucous membrane, and, therefore, the normal organs are at first actively stimulated to rid themselves of the irritating foreign substance. It is not strange, therefore, that this preservative had a marked stimu- lative action on those organs and cells secreting the various diges- tive juices. _It is evident that when the digestive and excretory organs of the body are excited to unusual activity by such an ex- traneous body having neither food nor condimental value, they act in self defence, and it would be wholly illogical to conclude from 1908.] UPON HEALTH AND METABOLISM. 321 this increased excitation that these bodies were helpful to digestion and conducive to health. The nature of the investigation made it impossible to determine whether any organic change took place in the various organs affected, but it may be assumed that any such change which these organs had undergone in the limited time was not sufficient to disturb in any notable way their normal functions which they would perform until the continued administration of the drug produced disease due to the excessive stimulation. In the case of phosphoric acid, the increased katabolic activity is difficult of definite interpretation, though it is established beyond doubt that such an effect is produced. The formaldehyde may exert a selective action for those proteid bodies high in phosphorus, rendering them insoluble, but in this case there would be an excess of phosphorus in the feces, which is not found. Or the formalde- hyde may induce a change in the process of digestion whereby the phosphorus of the food is changed into a soluble and easily excreted form without passing through the tissues of the body. This might easily be the case if in the process of. digestion the glycerol-phos- phoric acid formed is transformed into soluble inorganic salts, which are readily excreted. Whatever may be the explanation, the changes indicated in normal metabolism, accompanied as they are by the development of the symptoms described, can only be consid- ered as prejudicial to health. The general tendency to produce a slight decrease in the tem- perature of the body, assuming for the moment that the data war- rant the conclusion that such a condition of affairs existed, might well be due to the inhibition of cell activity shown by the retarda- tion in the breaking down of tissues. The normal functions of the body would doubtless be disturbed by such a condition, aside from the irritating and other disturbing influences exerted by the exhib- ited drug. The tendency of the preservative to produce albumin in the urine, while not well marked, is at least worthy of attention. The fact that only slight changes take place in the body weight is suffi- ciently explained in the data and cannot be urged in favor of the exhibited preservative. Apart from the injurious effects of formaldehyde itself, its use 322 WILEY—INFLUENCE OF PRESERVATIVES [April 25, as a food preservative would be especially inadvisable in milk or cream, because its addition in dilute solution prevents the growth of acid-forming bacteria, but has no effect in retarding the action of many harmful organisms; in other words, the milk is prevented from becoming sour and thus indicating its age and the danger sig- nal is thus removed, while the other organisms which are capable of producing disease continue to multiply in the milk with practically the same degree of rapidity as if the formaldehyde was not present. The final conclusion, therefore, is that the addition of formalde- hyde to foods tends to derange metabolism, disturb the normal func- tions, produce irritation and undue stimulation of the secretory activities, and, therefore, it is never justifiable. Sulphate of Copper.—The data which have been collected in the course of this experiment have led to the conclusion that the administration of sulphate of copper even in the extremely small quantities in which it has been given has a very distinctly unfavor- able effect upon health and digestion, as indicated by the ordinary clinical and medical summaries. Severe pains are produced in the stomach accompanied often with nausea and sometimes with vomit- ing, there is a general tendency to malaise, often a development of headache, and other unfavorable symptoms of a more or less per- sistent and uniform character. Further than this, the symptoms which are usually not developed for about a week continue in some instances for a number of days into the after-period after the sul- phate of copper has been withdrawn. The data indicate that cop- per, like many other metals, is likely to produce a cumulative effect, and that its administration in even much smaller quantities than those indicated, or less than those which would be ingested in the regular consumption of coppered vegetables, is attended with more or less danger on this account. There was a very small loss of weight in nine of the subjects, while the three who showed the greatest tolerance of the copper sulphate gained in weight. No definite conclusions can, therefore, be formed respecting the general effect upon the weight of the body, except that in the cases where uniform effects are produced there is a slight loss of weight. The copper salt which was used in this experiment differs from / 1908.) UPON HEALTH AND METABOLISM. 323 other chemicals which have been used in this series of investigations in that its excretion falls only partly upon the kidneys. The effect produced on the urine, therefore, cannot be ascribed directly to the copper salt employed, but only to such derangements of the metab- olism due thereto as would incidentally affect the composition of the urine. The effect upon the general metabolism is of a character which, though not very pronounced, is indicative of a retardation of normal metabolic processes. Inasmuch as a small quantity of sulphur was introduced into the system through the copper salt, the quantity of this sulphur must be taken into consideration in studying the effect on metabolism. There is seen to be quite a uniform tendency to derange the ratio of the metabolized sulphur and nitrogen. The apparent increase in the relative quantities of sulphur ex- creted is due rather to the diminution in the nitrogen than to an actual increase in the sulphur over that which would be expected from the ingestion of the sulphuric acid in the copper salt. The most marked change in the sulphur compounds is in the case of neutral sulphur, which shows a decided and uniform increase dur- ing the administration of the copper salt and in some cases for several days thereafter. The effect produced upon the metabolism of nitrogen is more important. Under the administration of sulphate of copper there is a marked and constant decrease in the excretion of urea, which is a matter of great significance. Such a decrease can only be regarded as an indication of a retarding effect on nitrogen metab- olism. At the same time the quantity of uric acid and xanthin bases are increased during the administration of the copper salt and the increase in xanthin is still very marked in the after-period. These two important observations indicate that the nitrogen metab- olism is disturbed in a way which must be considered injurious to health. There is also a notable effect produced upon the phosphoric acid metabolism. There is a marked decrease in the total metabolized phosphorus, and, while the non-metabolized phosphorus is less uni- formly affected, there is a decided tendency shown to decrease the 324 WILEY—INFLUENCE OF PRESERVATIVES [April 25 total excretion of phosphoric acid under the influence of the copper sulphate. The final conclusion, based on the medical and clinical data and on the study of the effect of the copper sulphate upon metabolism, is that the administration of this salt is prejudicial to health, Potassium Nitrate-——It is evident that the administration of small quantities of potassium nitrate induce only slight disturbances in the metabolic processes, and indicate only to a slight degree harm- ful or deleterious effects as noted in the medical and clinical data. It is evident moreover that with the exception of one instance, namely, the increase of the number of red corpuscles in the blood, that no beneficial effect can possibly be attributed to the exhibition of this chemical. While the data are in this case far less conclusive than those in any of the preceding cases, they are of a character to warrant the suggestion that so far as health and digestion are concerned it is safer to omit a body of this kind from the food, There are some foods which naturally contain small quantities of potassium nitrate. Its very poisonous action when taken in large doses, however, is a warning which should cause great care in its use even in small quantities and deter any one charged with the protection of the public health from expressing any favorable opinion in respect to its use. It is evident that potassium nitrate in the quantities used has neither a preserving effect nor has it any condimental value. What- ever may be said to the contrary, it is perfectly evident that the sole purpose of its use is the intensification of the red color of meats after preservation. Whatever may be the ethical principle under- lying this use of potassium nitrate is a question which is not the subject of discussion in a bulletin of this kind, but it is only due | to the consumer that the real purpose of using potassium nitrate in the curing of meats should be revealed. The further question arises as to whether or not the coloring of preserved meats in this way in order that they may have the color of fresh meats is a violation of the Food and Drugs Act, which forbids the coloring of food products for the purpose of con- cealing damage or inferiority. 1908.] UPON HEALTH AND METABOLISM. 325 While, therefore, the data which have been accumulated are not such as to warrant a sweeping condemnation of potassium nitrate in foods, they are sufficiently indicative to justify the conclusion that its presence in foods is undesirable and open to suspicion. GENERAL CONSIDERATIONS. Having thus set forth the general results of this long and labor- ious study, it is seen that if the conclusions based upon the experi- mental data are correct that there can be no justification of the proc- ess of adding chemical preservatives to human foods. Successful manufacturing establishments have demonstrated beyond peradven- ture that better, more wholesome, and more permanent forms of food products can be produced without the aid of any preservative what- ever. Sterilization will preserve sweet cider better than benzoate of soda. Proper care in handling fruits and in conducting the manu- facturing processes for preserves, jams and marmalades will make a more palatable product and one that keeps better than the use of salicylic acid. Careful curing of meats and proper care in trans- portation will preserve these meats better than boric acid. The natural color of the pea kept in a sanitary can where its color is not lost by action due to imperfections of the tin will make a far more palatable article than will the use of sulphate of copper, and so on to the end of the list. There is no single food product which is not more palatable and of equal if not better keeping qualities when made carefully without the use of preservatives. There is, therefore, absolutely no commercial necessity for the use of these bodies, but it is urged by those who employ them that even though considerable quantities of these bodies are injurious to the health, which no one denies, yet in the minute quantities in which they are used in foods they can not be regarded as in any way deleterious. It is easy to show that such an opinion is without scientific basis. It is quite impossible for any expert who holds this opinion to indi- cate to any jury, much more to the great jury of the American peo- ple any point in the addition of the preservative to food at which it remains harmless, or the point at which it begins to be harmful. Unless such a point could be fixed and demonstrated upon reliable 326 WILEY—INFLUENCE OF PRESERVATIVES [April 2s, experimental data, it is evident that no scientific reason can be urged for the use of limited quantities of a preservative, which is acknowl- edged to be harmful, on the ground that in such quantities it is not injurious. Inasmuch as a preservative is not a food, and as it does not in any way take part in the nourishment of the body nor in the res- toration of waste or growth; and further as it is necessarily elimi- nated, either unchanged or in other forms which may be even more harmful than the original, by the excretory organs of the body, thus imposing upon them an unnecessary and injurious burden and affect- ing more or less the constitution of the ultimate cells thereof in an unfavorable way, it is evident that the argument which would per- mit their use in small quantities is wholly illegitimate. The fallacy of the argument that small quantities of an injurious substance are not injurious may perhaps be best represented graph- ically. The chart which accompanies this discussion shows theoret- ically the normal and lethal dose of a food and a drug or, as in this case, a chemical preservative. The chart shows two curves, one representing a chemical preservative and one representing a food. The normal dose of a food is that quantity of food which maintains a healthy adult body in equilibrium. It is represented on the right of the chart by the number 100. If the quantity of food necessary to maintain the equilibrium in a healthy adult body is slightly dimin- ished, no apparent change is at first experienced and possibly even no discomfort. If, however, the quantity of food be still further diminished progressively, as indicated by following the curve down to the left, the point is finally reached when no food is given at all and death ensues, represented by zero on the left hand of the diagram designated “lethal dose.” As the curve begins to deviate from the perpendicular on the right the degree of injury is very readily noticed and starvation or symptoms of starvation are set up. Thus, if you follow the perpendicular on the right downward to the point 80, the divergence of the corresponding point of the curve is already measurable. As you descend to zero the magnitude of the measurement increases. It requires but very little further illustra- tion to show how easily the effect of diminishing the normal dose of 1998. ] UPON HEALTH AND METABOLISM. 327 a food can be measured immediately after the curve begins to vary appreciably from the perpendicular on the right. Let us now consider the perpendicular on the left, which is marked at the top under the term “ lethal dose,” viz.; a quantity of the added preservative sufficient to destroy life. The normal dose of such an.added chemical preservative is 0, and is shown at the base line to the right marked “ normal dose.” If you add a very minute quantity of a chemical preservative, the curve representing it varies LETHAL DOSE NORMAL DOSE 100 100 80 r60 40 r20 ite eke zh - LETHAL OOSE @5 50 13° NORMAL DOSE Fic. 1. Graphic chart representing the comparative influences of foods and preservatives. so slightly from the horizontal base as to be impossible of measure- ment by ordinary means. If we follow.along to the number 75, on the horizontal base, we see the deviation of the curve is sufficiently great to measure. At 50 it is still greater, at 25 still greater, while at the left of the basic line it is a maximum, extending from o to 100, or the lethal dose. It is easy to show by mathematical data that no matter how small the quantity of an injurious substance or pre- servative is, it will still produce an injurious effect, which may be infinitely small if the dose be infinitely small. It follows then, as a 328 WILEY- INFLUENCE OF PRESERVATIVES [April 25, mathematical demonstration, that any quantity of an injurious sub- stance added to a food product must of necessity be injurious, pro- vided it is in the nature of 4 drug and the body is in a perfectly healthy normal condition. Hence the argument which has been so persistently urged in favor of a chemical preservative that if in small quantities it is harmless is shown to be wholly untenable. Where there is no neces- sity for the addition of a harmful substance, where no particular benefit is secured thereby, and where there is no disturbance of the normal state of health there can be no possible excuse of a valid nature to offer for the exhibition of even minute quantities. That these minute quantities would not be dangerous, in so far as pro- ducing any fatal effect is concerned, is conceded, but that, in the end, they do not produce any injury, even in these small quantities, is certainly to be denied. The course of safety, therefore, in all these cases is to guard the opening of the door. If the use of small quantities is permitted, then there can never be any agreement among experts or others respecting the magnitude of the “small quantity,” and continued litigation and disagreement must follow. On the other hand, when the harmfulness of any substance which it is proposed to add to food is established and no reason for its use can be given other than the convenience, carelessness, or indifference of the manufacturer, | the exclusion of such bodies entirely from food products follows as a logical sequence and a hygienic necessity. THE HUMMING TELEPHONE, A CONTRIBUTION TO THE THEORETICAL AND PRACTICAL ANALYSIS OF ITS BEHAVIOR. By A. E. KENNELLY anp WALTER L. UPSON. (Received July 20, 1908.) The following paper describes the salient features of an experi- mental research on the humming telephone, conducted in the Gradu- ate School of Applied Science of Harvard' University during -the year 1907-08, and discusses an elementary mathematical theory which the observations appear to indicate and support. Definition —A “ humming telephone” is a connection of: 1. A telephone receiver, or ordinary hand ’phone. 2. A telephone transmitter, or ordinary carbon microphone. 3. A source of electric power, such as a voltaic battery and tele- phone induction coil, with the receiver in such electric and acoustic relation to the transmitter, that it is able to emit a sustained note or hum. This auto-excited hum may be so loud as to be heard in a distant room through several partitions. Historical Outline-—The fact that a telephone receiver held, either in contact with, or close to, the face of its transmitter may cause the production of a hum or singing tone, appears to have been first observed by Mr. A. S. Hibbard. This experimental fact is now well known to telephonists. In many cases, it is only necessary to lift a subscriber’s telephone from its hook, and hold it face to face with its transmitter, in order to produce a loud hum. The only published investigation of the humming telephone that ‘the authors have succeeded in finding is an important paper by Mr. *“Tnvestigation of the Phenomena of ‘The Humming Telephone,’” by Walter L. Upson, a thesis towards the degree of master of science in elec- trical engineering, Harvard University, 1908. * September, 1890. See Gill’s paper hereafter referred to. 3829 330 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, F. Gill,? read before a meeting of the Dublin Local Section of the Institution of Electrical Engineers in April, 1901. Very briefly, the salient experimental facts reported in this valuable paper are: 1. The reversal of the telephone receiver connections in the cir- cuit alters the pitch of the auto-excited tone, the pitch being higher for one direction, and lower for the other direction, of connection. 2. The pitch of the tone may also be altered by changing: (@) the inductance, capacity or resistance of the circuit, or circuits; (0) the strength of current in the microphone transmitter; (c) the dis- tance between the receiver and transmitter idiaphrogiias (d) pres- sure on either of the diaphragms. The Gill paper does not discuss the theory of the subject beyond suggesting that the phase retardation of the acoustic impulses reach- ing ‘the transmitter from the receiver has a controlling influence on the pitch of the tone. The research reported in this paper may be regarded as extend- ing the investigation from the stage reached in Gill’s paper to a stage which admits of a first approximation theory. A large amount of research remains, however, to be carried on in the future, before the experimental and theoretical analysis of this fascinating but complex phenomenon can be regarded as satisfactorily nearly complete. : - Method of Observation Employed.—As pointed out in Gill’s paper, the pitch of the note emitted by the humming telephone, although substantially constant under fixed conditions, is affected by almost any change in the apparatus, in a seemingly most intricate manner. In order, therefore, to study the effect of varying one particular variable at a time, the device was hit upon of acoustically connecting the receiver and transmitter diaphragms in a definitely controllable way by means of telescoping tubes fitting on to the receiver and transmitter faces. These tubes, and also the standard electric connections employed, are indicated in Fig. 1. The transmitter was kept stationary, with one end of the tube covering and secured to its cone. The receiver was fastened, on a sliding wooden carriage, to the other end of the telescoping tube. *“ Note on a Humming Telephone,” by F. Gill, Journal of the Institution of Electrical Engineers, 1901-02, Vol. XXXI., No. 153, pp. 388-399. 1908.] KENNELLY AND UPSON—HUMMING TELEPHONE. 331 The distance between the faces of the two instruments could be varied at will by pulling out, or pushing in, the telescoping tube- sections. The average current in the primary circuit was measured with a Weston d.c. milliammeter. The pitch of the humming note was measured approximately by the ear, with the aid of a number of short organ pipes, and, in some instances, with the aid of a violin. The voltaic battery used consisted of a selected number (from two to nine, but usually four) of 25-ampere-hour lead storage cells. The reversing switch in the secondary circuit enabled the receiver ter- minals to be reversed at will. Transmitter. Freceiver. ml aetieee Sinai Tube Length ea - /il-Ammeter : : fi Sy A. iI i\k pe Ea, S dl “ke ‘i * Battery. Induction Coil. freversing Switch, Fic. 1. Diagram of Humming Telephone Connections. The Telescoping Tubes.—The tubes were made of heavy wrap- ping paper. Their internal diameters varied from 5 cm. (2 in.) to 6 cm. (24 in.). They were used in lengths of 65 cm. (254 in.), with a few shorter and longer sections for special measurements. The substance of which the tubes was composed did not appreciably affect the observations. It was found, however, that if the tele- scoping sections did not fit fairly tightly, erratic results were ob- tained. Closely fitting sections were used. The Transmitters.—The transmitters used were of the standard Western Electric Co. type and manufacture. The diaphragm in these instruments was of aluminum, 6.32 cm. (2.49 in.) in total diameter, and 0.55 mm. (0.022 in.) thick, over a coating of Japan varnish on one face. The diaphragm was loaded at its center with one of the disk electrodes of the carbon microphone. The dia- phragm was damped by being clamped between rubber rings to an 332 KENNELLY AND UPSON—HUMMING TELEPHONE. [july 20, internal diameter of 4.8 cm. (1.9 in.), and also by the application of a pair of rubber-tipped flat metal springs to areas between the center and edge. The resistance of the microphone varied between the approximate limits of 20 ohms when quiescent, and 110 ohms when in powerful vibration. 7 The Receivers.—The receivers used in most of the measurements were of the standard bipolar Western Electric Co.’s type, known as No. 122, having poles 1.4 X 0.2 cm. (0.55 X 0.08 in.), separated by 0.82 cm. (0.325 in.). They had a resistance of 210 ohms, and an inductance of 0.025 henry, at a frequency of 1,000 ~. With steady currents, their resistance, at 15° C., was about 70 ohms. The diaphragm of varnished ferrotype iron had an external diameter of 5.5 cm. (2.17 in.), a clamping diameter of 4.95 cm. (1.95 in.) and a thickness, over varnish, of 0.292 mm. (0.0115 in.). Its weight was 4.0 grammes. The Induction Coil.—The induction coil used was of the standard Western Electric Co.’s type, known as No. 13. Its resistances and inductances were taken as follows :* ; TABLE I. ; 3 7 Frequency Resistance at 18° C. | Self-Inductance. : Mutual Sycles per ; Y nductance, : Primary Secondary Primary Secondary salar Ohms. Ohms. Henrys | Henrys. Henrys: fe) 1,62 | 20.3 | ! 1,000 3.2 48.1 | 0.0765 0.0172 The principal dimensions of the coil were: Length over all 8.2 cm. (3.16 in.). Interflange 6.3 cm. (2.5 in.). Diameter over out- side cover 2.5 cm. (1 in.). Internal diameter of core tube 0.75 cm. (0.296 in.). Diameter of iron wires in core 0.0356 cm. (0.014 in.). Total number of iron wires in core about 75. Observation Series No 1. Effect of Shortening the Tube.— Commencing with the connections of Fig. 1, a battery of 8.6 volts, and a tube length of 267 cm., as indicated in Fig. 2 on the scale of abscissas, a loud steady note between G”’# and A” (850 ~) was sus- tained in the telephone. The pitch of this note is shown at P on the “The data for the coil at 1.000 ~ were kindly supplied by the engineering department of the Western Electric Co. 1908.] KENNELLY AND UPSON—HUMMING TELEPHONE. 333 upper ziz-zag line J. The current strength, on the d.c. milliammeter, as shown at p on the lower ziz-zag line J, was 130 milliamperes. When the telescopic tube was gradually shortened, the pitch of the note steadily rose, until it reached Q, at A’* (920~), with 240 em. of tube-length, and a primary current strength q of 200 mas. The intensity of the note near 920~ was ordinarily somewhat weaker than when near 825 ~. On continuing to shorten the tube, the pitch suddenly broke from Q, at 920 ~, to FR at 825 ~. Pushing va wah a N IN Bh AE ! f Sic SSS, NOTE FREQUENCY. 3 Z 7] eee ~ CURRENT - MILLIAMPERES. 8 ONES SS ES aa aS AB) HER GG RE TR OY WS SR a 60 80 100 720 «40 =—s/60—‘a8D— ROD RO RH BGO TUBE LENGTH - CENTIMETERS Fic. 2. Effect of Shortening Tube, and of Reversing Receiver Connections. in the tube further, the pitch would again climb steadily to T, at 201 cm., with a new maximum of current. Beyond this point, the pitch would break suddenly to U at 810 ~. Again it would climb to W, at 170 cm. and suddenly collapse to X. Continuing in this manner, the pitch would alternately rise to maxima and break sud- denly to minima, along the pitch zig-zag J. At the breaks of pitch, the current would sometimes break to a lower value, as at t, u; or break to an upper value, as at w, x; or vary suddenly in rate of change, without discontinuity in magnitude, as at g. Repeating the experiment, the zig-zag lines of pitch and of current would be repeated, not exactly but substantially, the variations being due not PROC. AMER. PHIL. SOC., XLVII, 189 V, PRINTED OCTOBER 2, 1908. 334 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, / merely to observational error, but also to variations in the behieiay of the transmitter. The zig-zag pitch line PQRST is found to be somewhat irregu- lar. The slants are by no means regularly parallel. The breaks QTW are neither regularly elevated, nor regularly spaced. The only substantial regularity is in the spacing along the pitch line G’# of 825 ~. The intersections of the ascending branches with this line lie approximately 40 cm. apart, at I10, 150, 190, 230 and 270 cm., or in accordance with the series 30 + 40m cm., where m is any positive integer. As regards the current curve pqrst, its points of minima 9, 7, v, etc., correspond fairly well to the ascending intersections of the pitch line with the line of G’# 825 ~. The points of maxima gq, t, 4, etc., occur near to the breaks in the pitch QO, T, W, etc. Minimum primary current was noticed to be associated with maximum micro- phonic activity of vibration. Feeble action in the microphone, on the other hand, was found to be associated prdmarily with increase of primary current. Observation Series 2. Effect of Shortening the Tube with Re- versed Receiver Terminals——Curves IJ, in Fig. 2, represent the behavior of note pitch and primary current, as the tube was short- ened from 265 cm, to 80 cm., with the terminals of the receiver reversed. Their general characters are similar to those of curves J. The two sets of curves indicate the effect which would be produced by reversing the receiver terminals at any particular tube-length within the above range. Thus, at S, or 220 cm., a reversal would lower the pitch from 870 ~ on curve J to K, at 810 ~, on curve JJ. On the other hand, a reversal made on curve J, at V, of 825 ~, would raise the pitch to N of 900 ~ on curve JJ, so that whether the reversal produces a rise or fall of pitch depends, in general, upon whether the reversal is effected above or below the mean pitch of G”’#, 825 ~. The only apparent regularity in the pitch line JJ lies in the spacing of the ascending intersections with the line of mean pitch Gt (825 ~). These occur near to 90, 130, 170, 210 and 250 cm. of tube-length, or according to the series 10+ 40m cm. On the mean-pitch line, the ascending intersections of one curve lie ap- 1908. ] KENNELLY AND UPSON—HUMMING TELEPHONE. , 335 proximately 20 cm. from, or midway between, those of the other curve. The note frequencies and primary current strengths for tubes of less than 60 cm. in length are given in Fig. 3, commencing at 60 cm. and shortening down to about 1 cm., when the receiver face came into contact with the transmitter face (cone removed), and so prevented closer approach. Curves J and JJ of Fig. 3 correspond 1300 1200 400 1000 NOTE FREQUENCY. CURRENT = MILLIAMPERES. | | l | 70 20 30 40 0 60 TUBE LENGTH - CENTIMETERS Fic. 3. Humming Note Frequencies and Primary Current Strengths with Short Tubes. to curves J and JJ of Fig. 2, respectively, and indicate the effect of reversing the receiver terminals. It may be observed that follow- ing the pitch line J, the ascending branch intersects the mean fre- quency line of 825 ~, at a tube-length of 30 cm., for the last time. 336 ,»XENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, Shortening the tube beyond this point, the pitch rises until it reaches e’” of 1,300 ~, at 12.5 cm., and at a primary current strength of 300 mas. Here the note breaks without descending to a new low note. There is silence with this connection of the receiver between 12.5 cm.’and o cm. With the transmitter and receiver touching each other, it was possible to produce almost any note between 620 ~ and 1,300 ~, by giving suitable opening to the air at one side. If, however, the outside air was shut off, and the air between the transmitter and receiver diaphragms was cylindrically enclosed, by bringing their faces into full opposition and contact, no note could be obtained. If we follow pitch curve JJ, we find that the ascending branches intersect the mean-frequency line at 50 cm. and at 10 cm. The pitch 866 ~ was obtained steadily when the transmitter and receiver faces were in full contact, corresponding to a “tube-length” of I cm. With this connection of receiver terminals, no other note, or variety of notes, could be obtained at contact. A telescoping tube of 9 meters (29.5 ft.) total icc was used in one series of measurements, and the results appear in Fig. 4. They were all obtained with diminishing tube-lengths, or with com- pression of the telescoping “tube. The small crosses indicate dis- continuities produced at the removal of sections of tube when finished with. In regard to the pitch line, it will be seen that it corresponds to curve J of Figs. 2 and 3. That is, it crosses the mean-frequency line of 825 ~ ascendingly at 30-+ 40m cm. with a fair degree of precision. With the shortest tube, the range in pitch-frequency was from 740 ~ to 1,060 ~, or through 320 ~. At the full length of 9 meters, this range fell to 75 ~. The ultimate limit tended apparently to the mean-pitch frequency of G’# 825 ~. The average note was above this pitch; but this was probably be- cause the tube was being compressed. Reference to Fig. 5 will show that, when shortening the tube, the average pitch lies above the mean of 825 ~; while in lengthening the tube, the average pitch lies below. The primary current strength in Fig. 4 tends, in general, to minima at the mean-frequency pitch of 825 ~, and to maxima at the breaks. The differences in current strength become, however, 337 KENNELLY AND UPSON—HUMMING TELEPHONE. 1908. ] ‘yMoIID Aiewiig UI SOA 9'g ‘YIBuN'T ur psonpey ATIpeay}s ‘swd 0z6H 0} dn sy}suaf-aqny, JOf sadinD Juaiing Aseunsig pue Aouonbesy ‘v ‘OT "SUILIWILNIO - HLONTT 39NL 025 088 Ong 003 OSL ORL 089 Ong ooo 9S oes OStr Oth 00h oe oz ose One 002 09o/ oer 08 On I T T T T i} T aR T bs T T I T T Fae 9 T T T T zi 09 “w J od Ne NA SU WV ES to Et Aaa Pg [SSE ONS aR, a Fes aa I \ | ont | 09/ | og 008 —loze p ae oe wee N wt ni we > ast oo NS SSS RS S 7 ae ‘ Nt tN | cos i LAN | oes B= 5 T T : Cae “ ) ma) logo. "STUIAWVITIIW + LN388ND ‘AININOIYS ILON 338 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, less, marked as the tube is longer, the minimum currents rising, as the length increases, by about 40 mas. in 9 meters, indicating steadily reduced action in the transmitter with increasing distance. Since the current rose to 260 mas. when the transmitter diaphragm was entirely out of action, we should expect, at this rate, to be able to sustain the humming note to a total tube-length of 40 meters; but no tests were actually made beyond 9 meters. > 920 Pom & whe . at z as 00 nN ae i. I H tual . a! oe : ' ye Hike oi) Hg aN lots Ip: NWSE} Ge = g00 I; ne Te py yo: Sy cee H us oem whee esi, Ge Set Sn aa ES en: NE: ot a Sis a = el N “MI N pe NT Fe _ 240 7) i 220 td = #0 = 160 . - “Mo , 4 te 720 55 o “2 MP Mess SD WR ee We Gece tk cen, oe Wace! feos ce! Oa MO 60 8 0 (20 Wo 60 (80 200 220 240 260 TUBE LENGTH - CENTIMETERS. Fic. 5. Effect of Lengthening and Shortening the Tube. Observation Series 3. Effect of Lengthening the Tube.—Fig. 5 indicates the relative effects produced by lengthening, as compared with shortening, the telescoping tube joining the transmitter and receiver in Fig. 1, using the same apparatus and connections as in Figs. 1, 2, 3 and 4. The heavy or continuous lines in Fig. 5 show the effects of shortening the tube, or correspond to curves J in Fig. 2. The broken lines show the effects of lengthening the tube. It will be observed that the points of maximum and minimum current agree fairly well. The ascending intersections of the pitch lines with the mean-frequency line of G’# 825 ~, lie near together, and approximately conform to the series 30 + 40m cm. of tube-length. The points of break in pitch do not, however, agree, and the dis- 1908.] KENNELLY AND UPSON-—-HUMMING TELEPHONE. 339 tances between corresponding pairs of breaks in pitch increase as the tube-length is greater, being 4 cm. at A, 9 at B, 11 at C, 13 at D, and 15 at E. Although not shown in Fig. 5, owing to limi- tations of space, it was found that these distances between corre- sponding breaks continued to increase until they reached about 20 cm., after which they shortened again to commence a new expand- ing series. ' 25 N al 103° a 3 coe vats Meh 77 af = 1 fs El ie Peis a) | o i Ge i v N + ! us 800) | \ ee gape) Tes .! gs ea 4 eeu e sci <—453 ae 725| ve 450 ‘ » és 4O | 4! P t ac 30) |! i a ¥ | = /20 \ 1 = R v 4 0 ; = . We u = 7 <= 80 co a 70 x | | | | | | 90 100 io 120 130 140 TUBE LENGTH - CENTIMETERS. Fic. 6. Humming Cycles with Cyclic Changes in Tube-length. Observation Series 4. Effect of Alternately Reversing, or Re- ciprocating, the Motion of the Tube. Humming Cycles—If, when compressing the telescopic tube, and when the note broke from a higher to a lower pitch, the tube was immediately extended again, the note would continue to lower in pitch for a little while, and then break back to a higher pitch. By moving the tube in and out,,like 840 KENNELLY AND UPSON—HUMMING TELEPHONE. [july 20, a concertina, over this range, the pitch would break to and fro in a very regular way. The corresponding reverse action would also occur if the motion commenced with extension. These conditions are shown in Fig. 6. Commencing at the point O, with 110 cm. of tube-length, on the mean frequency of 825 ~, if we shorten or compress the tube to 90.5 cm., we reach P at 900 ~, near A”. The note then breaks to Q at 780 ~. Increasing the tube-length back to 95 cm., we reach R at 770 ~. The note then breaks up- wards to S at 880 ~. This humming cycle PQRS, could be repeated indefinitely with a considerable degree of precision as to pitch and tube-length; but with a more’ moderate degree of precision as to primary current strength. Similarly, the cycle TUVW, of 10.5 cm. amplitude in length, and 100 ~ amplitude in pitch, might be re- peated indefinitely. The amplitudes and areas of these humming cycles vary at different breaking points. Purity of Humming Tone—With the greater tube-lengths, shortly before the break of pitch occurred, there was frequently noted an appearance of the new tone in advance. As the breaking point was approached, the old tone dwindled, while the new tone strengthened. At the break, the old tone, already faint, would sud- denly cease. Consequently, before breaking, both the old and new tones might be recognized, forming a sort of trill, or combination tone. This association of simultaneous tones had the effect of main- taining the primary current strength more nearly uniform. With the shorter tube-lengths, which involved a greater jump of frequency at the breaks, these combination tones were rarely heard, and the old note would break suddenly into the new note without any suggestion of a trill. In some of the observations, the notes, aside from the above- mentioned trilling near to the breaking points, gave acoustical evi- dence of multiple tones. Occasionally, the principal tone was accom- panied by an octave overtone. The octave might be either the first octave below, or the first octave above, the principal tone. Such overtones were comparatively faint. At other times, the superposed tone, instead of being harmonic to the principal tone, appeared to differ therefrom by only about one tone on the musical scale. This inharmonic superposed tone was also relatively faint with respect 1908, ] KENNELLY AND UPSON—HUMMING TELEPHONE. 341 to the principal tone. Generally, however, no superposed tones could be discerned, and the note was clear and flute-like in quality. Irregu- larities in the fitting of the telescoping tube-sections, or in other acoustic connections, were found to be productive of superposed notes. " EFFECTS OF ELECTRICAL CHANGES. Observation Series 5. Effect of Resistance in Primary or Sec- ondary Circuit.—In this test a single tube of constant length (86.5 cm. or 34 in.) was used. It was of pasteboard, had an internal diameter of 5.1 cm. (2 in.) and weighed 113.5 gm. This length happens to be about midway between the ascending intersections of “pitch lines J and JJ in Fig. 2 measured on the mean-frequency line of 825 ~. That is, the tube-length selected favored each of the lines I and JJ nearly equally. The battery e.m.f. of 8.6 volts was the same _as in all the above described measurements. The same telephone receiver and induction coil were also used. Substantially non-induc- tive resistance was introduced, by rheostat, into either the primary, or the secondary, circuit at will, leaving the connections of Fig. 1 otherwise unchanged. After starting the loud humming note with no extra resistance in either circuit, resistance was gradually inserted into the primary circuit until the note, diminishing in amplitude, finally disappeared. The extra resistance in the circuit at the extinction of the tone was recorded, under the name of “ extinguishing resistance.” Resistance was then withdrawn from the primary circuit, and, after the loud note had been reéstablished, was introduced gradually into the sec- ondary circuit, until again the note was extinguished. The second- ary extinguishing resistance was likewise recorded. The same tests were repeated with the telephone receiver terminals reversed. It was found that both the primary and secondary extinguishing resistances repeated themselves very fairly (within about 5 per cent.) in successive trials. In order to obtain the best comparative results in successive tests, it was found desirable to tap the transmitter gently when approaching the condition of extinction. The pitch of the tone when enfeebled almost to extinction by extra resistance, in either the primary or secondary circuit, was always close to the mean frequency of 825 ~. 342 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, The amount of either the primary or secondary extinguishing resistance was found to depend upon the adjustment and operative condition of the transmitter, keeping the receiver, tube-length and all other conditions unaltered. This led to a trial of this method as a practical test of microphone transmitters. Observation Series 5a. Test of Transmitter by Hum-extin-- guishing Resistances—A number of transmitters, some good and others imperfect, were tested under the conditions above outlined. These transmitters were kindly loaned for this purpose by the West- ern Electric Co. Twelve were regular standard instruments that had already satisfactorily passed the factory tests. These were labelled T, to T,, respectively. Four more were marked defective_ and “ down in volume.” They were labelled T,,, T,;, Ty, and To,. Four more were marked defective and “thick in quality.” These were labelled 7,,, T,,, T,. and T,,. Yet another four were marked defective and “ burning.” These were labelled T,,, T,,, T2) and T,,. ~ Defective transmitters “ down in volume” are recognized as weak. Those which are of “thick quality” are strong but defective in articulation. Those which are “burning” produce slight arcing, at or near the electrodes, when subjected to normal conditions of operation. The results of the tests on these 24 transmitters are given in the accompanying table; where FR represents the primary, and r the secondary, extinguishing resistance, when the transmitter was gently tapped. Care was taken that the observer in this test did not know the label number, or reported condition, of the transmitter under trial. It will be seen that with the good transmitters, the mean primary extinguishing resistances were all included between 26.5 and 58.5 ohms, their mean secondary extinguishing resistances be- ing between 1,925 and 4,150 ohms. All of the defective transmitters lay outside these limits, the “ down in volume” being low, and the “thick quality ” high, in their extinguishing resistances ; except two of the “ burning” type, which fell within the good secondary extin- guishing resistance limits. It would seem, therefore, that this re- sistance method constitutes a possible practical application of the humming telephone to transmitter testing; except that “burning ” transmitters may require a separate test for their detection. ™~ 1908, | KENNELLY AND UPSON—HUMMING TELEPHONE. 343 The results recorded in the last two columns of Table II. are pre- sented graphically in the target diagram of Fig. 7. The square in- cludes all the good instruments and none of the bad. The mean of the good transmitters is indicated by the solid black circle. Tas_e II. Table of Comparative Hum-Extinguishing Resistances for 12 Good and 12 Defective Transmitters. Extinguishing Resistances, swan a cee saat ist Position of Rec’r, 2d Position of Rec’r, bbe Seed sity a R (Pri). por (See.)e cf GP ri.) rv (Sec.). Ty 43 3,100 50 2,300 46.5 2,800 T, 23 3,050 44 3,000 33.5 3,025 Ts 55 4,300 43 4,000 49 4,150 ie 25 2,300 31 1,900 28 2,100 T; 45 3,900 40 2,600 42.5 3,250 OK, Te 31 3,000 69 3,800 50 3,400 7, 27 2,600 26 1,600 26.5 2,100 Es 30 2,600 30 1,700 30 2,150 Tg 31 2,700 44 2,300 37.5 2,500 Tyo 47 3,900 46 3,900 46.5 3,900 Tu 43 4,100 74 3,800 58.5 3,950 Tis 33 2,600 21 1,250 27 1,925 Mean 36.1 3,180 43.2 2,696 39.6 2,937 : Zis 10 750 10 700 fe) 725 Down 235 6 390 — — 6 390 in T46 6 goo 12 1,000 9 950 Volume, YF, 17 1,400 20 1,500 18.5 | 1,450 Mean 9.75 860 14 1,070 10.9 879 = an 62 |; 4,900 66 2,300 64 3,600 Thick Thy 50 9,000 70 10,000 60 9,500 Quality 22 52 7,000 75 8,000 63.5 7,500 r ye 66 5,300 78 6,700 72 6,000 Mean 57.5 6,550 72.5 6,750 64.75 6,650 Ts 54 3,800 68 3,400 61 3,600 : Ty | 6 | 4700 | 93 | 6900 | 77 5,800 Burning. Zo 82 5,300 102 5,000 g2 5,150 Ber 60 3,900 61 2,900 60.5 3,400 Mean 64.25 | 4,425 81 4,550 72.6 4,487 Observation Series 6. Effect of Varying the E.M.F. in the Primary Circuit.—Among so many variables and variations as are displayed in preceding diagrams, it is comforting to find one variable which produced relatively little effect within certain practical limits. Fig. 8 shows the frequencies and primary currents for tube-lengths RESISTANCE IN PRIMARY + OHMS. 344 100 90 80 70 60 50 40 30 20 40 F Lol G. NOTE FREQUENCY. CURRENT - MILLIAMPERES. Fic. KENNELLY AND UPSON—HUMMING TELEPHONE, [July 20, "al L g / ro L A. i : of ii @ # bane © of. o7e x pa: Key ie O G00d Transmitters. Py 7 O Down in Volume. e) © Thick Quality c Re Q Burning. , | | l | | | | | | l 1000 2000 3000 4000. =F5b00 6000 7000 8000 000 10000 RESISTANCE IN SECONDARY - OHMS. Target Diagram of Transmitter Tests by the Method of Hum Extinguishing Extra Resistance. 7: | 440 TUBE LENGTH - CENTIMETERS. Frequencies and Primary Currents for Different Primary E.M.F’s. | | 100 120 460 480 200 220 8. 1908.] KENNELLY AND UPSON—HUMMING TELEPHONE. 345 steadily reduced from 260 to 70 cm., with batteries of 3, 4 and 5 storage cells, respectively, in the primary circuit (6.5, 8.5 and 10.5 volts). The transmitter, induction coil, receiver and transmitter were all as in Figs. 1 to 6. It will be seen that the primary cur- rents have their respective maxima and minima in substantial agree- ment, the range of variation being naturally greatest for the largest battery, and least for the smallest. The ascending intersections of the frequency line with the mean-frequency line of 825 ~ are the same throughout, and conform to the series 30 + 40m cm., in agree- ment with line J of Fig. 2. The breaks in pitch do not all coincide ; but the differences in this respect are not great, nor can it be said 4 al Mea ae * ff Pe r* 4 ‘ ’ NOTE FREQUENCY. we ee eee to menn, CURRENT MILLIAMPERES. S | 80 100 420 140 460 480 200 220 240 260 TUBE LENGTH - CENTIMETERS. Fic. 9. Frequencies and Primary Current Strengths for Different Condensers in Secondary Circuit. that the biggest battery always produced the most retarded break. Moreover, excepting perhaps the break at 240 cm., the variations in breaking points are within the limits of variation obtained in suc- cessive series with one and the same battery. Observation Series 7. Effect of a Condenser in the Secondary Circuit—It was found that a certain magnitude of condenser capacity inserted in series in the secondary circuit had a marked effect on the behavior of the humming telephone. The results are 346 KENNELLY AND UPSON—HUMMING TELEPHONE. [july 20, indicated in Fig. 9, for a tube-length commencing at 270 cm. and steadily reduced to 75 cm., with 8.6 volts in the primary circuit and the same instruments as before. Three sets of curves are given, for 0.2 pf. (microfarad), 0.5 wf., and © pf. (condenser short-circuited), respectively. Referring to the pitch lines, it will be seen that there is not much difference between the cases of © and o.5 pf. The ascending branches of the zig-zags cut the mean frequency line of — G”’# at 90, 132.5, 175 and 210 cm. or fairly in conformity with the series 10 + 40m, as in curve JJ of Fig. 2. With 0.2 pf., however, the intersections with this line are at 100, 145 and 185 cm., or more nearly in conformity with the series 22 + 40m cm.; that is, at points displaced about 12 cm. further along the tube. Moreover, the-breaks occur at higher frequencies by about 40 ~. As regards primary current strengths, the minima in each series occur at substantially the points where the pitch line intersects ascend- ingly with the G’’? line. That is, the minima of o and 0.5 pf. are fairly close together ; while those for 0.2 pf. are displaced about 12 cm. further along the tube. Maximum currents occur near breaking points, as usual, EFFECTS OF MECHANICAL CHANGES IN INSTRUMENTS. Observational Series 8. Effects of Modifying the Transmitter. —In order to study the influence of changes in the transmitter upon the humming note, three similar Western Electric transmitters were selected, of standard type and quality, already referred to as T;, T; and T,,, in connection with Fig. 7. The receiver, induction-coil, battery and connections were as in previous tests. The comparative results with these three transmitters are shown in Fig. 10, for tube- lengths steadily reduced from 260 to 70 cm. It will be noted that the ascending intersections of the pitch lines all intersect the mean- frequency line of 825 ~ in substantial conformity with the series 30 + 40m, or in accordance with curve J of Fig. 2. The breaking points do not agree, No. 8 always breaking last at a higher pitch, No. 5 next at a medium pitch and No. 11 first at a lower pitch. It may also be noted that in the hum-extinguishing resistance-test of these three transmitters, as given in Table II., and in Fig. 7, their order of succession was the same. 1908, ] KENNELLY AND UPSON—HUMMING TELEPHONE. 347 NOTE FREQUENCY. ae = EEO ee me a me em - CURRENT + MILLIAMPERES. 60 80 400 120 440 460 480 200 220 240 260 TUBE LENGTH - CENTIMETERS. Fic. 10. Comparative Behavior of Three Regular Standard Transmitters with Reduced Tube-lengths. The test indicates, therefore, that different standard transmitters in normal adjustment do not alter the mean-frequency tube-lengths ; but that variations in breaking lengths may be expected within cer- tain limits. A further test was made of the effect of modifying the trans- mitter, by selecting for experiment a particular Western Electric Co.’s standard type of transmitter which had been used in the labora- tory for some years, and was not in the best adjustment. A test was made with this instrument (using the same receiver, coil, battery and connections as in preceding tests), first without any extra load on its diaphragm, second with a load, and third with the load re- moved. The load consisted of a small brass disk 1.5 cm. (0.59 in) in diameter, and 0.2 cm. (0.079 in.) thick, clamped at its center between the two small nuts at the center of the external surface of the diaphragm. This added a mass of 2.7 gm. to the vibrating system of the transmitter. The results are seen in Fig. 11. Curves I and 3 represent the behavior of the system unloaded, before and after loading respectively, the tube-length being steadily diminished 348 KENNELLY AND UPSON—HUMMING TELEPHONE. {uly 20, from 200 to 80 cm. Curves 2 represent the corresponding behavior when the diaphragm was loaded. The primary currents were all unusually large, probably owing to the imperfect adjustment of the transmitter. rom 2 CY 1000} "an 950\_ FI od 9001 4 f O4 Va Di NOTE FREQUEN -—-—-—|-—-+-— + —-— + — Z- ‘f—-1- 4-65 V4 ee w R 2. >. >. = Ww) Z iC) § 8 a ~ z } Ww] / / CURRENT + MILLIAMPERES. TUBE LENGTH - CENTIMETERS: Fic. 11. Test of a Transmitter with its Diaphragm Loaded and Unloaded. It will be observed that the loading did not appreciably alter the ascending intersections of the pitch lines with the G”# mean- frequency line, which occur in conformity with the series 20 +-40m cm. The loading seems to have somewhat lowered the range of pitch as a whole; or to have modified the conditions at breaking, without materially affecting the conditions at mean-frequency (825 ~). A number of trials with further modifications of the transmitter diaphragm substantiated the above stated results. In one case, a new experimental diaphragm of tinned sheet iron, 0.38 mm. thick 1908. ] KENNELLY AND UPSON—HUMMING TELEPHONE. 349 (0.015 in.), with parallel and opposite symmetrical sectors sliced off, was substituted for the regular diaphragm in the test transmit- ter. The primary current strength during activity was thereby in- creased ; but the G”# tube-lengths remained substantially unchanged at 30-++ 40m cm. Adding loads, altering the damping-spring pres- sure, or varying the other mechanical adjustments of the transmitter produced either complete silence; or else the usual G”#, at 30+ 4om cm. . The tests showed that modifying the transmitter alters the range and limits of pitch variation, as well as the primary current strengths; but does not sensibly alter the tube-lengths for mean- frequency. NOTE FREQUENCY. eRe ee FB gee e ~ 8 g CURRENT » MILLIAMPERES. S &0 400 120 440 460 180 200 220 240 260 TUBE LENGTH - CENTIMETERS. Comparative Frequencies and Currents with Three Different = = i) _ bo Receiver Diaphragms. Observation Series 9. Effect of Altering the Receiver.—In order to determine the influence of the telephone receiver diaphragm on the hum, three special receiver diaphragms were made up, each of soft transformer steel, 0.355 mm. (0.014 in.) thick, and 5.5 cm. (2.16 in.) in diameter, labeled D,, D, and D, respectively. D, was PROC. AMER. PHIL, SOC., XLVII. 189 W, PRINTED OCTOBER 2, 1908. 350 KENNELLY AND UPSON.-HUMMING TELEPHONE. [July 20, left. circular, D, and D, had symmetrical sectors cut from opposite sides, reducing their width to 4 cm. (1.57 in.) and 3 cm. (1.18 in.) respectively. In clamping these strip diaphragms in front of the bipolar magnet of the standard receiver, their angular position did not appear to affect the system appreciably. The results obtained with these three diaphragms are indicated in Fig. 12, for tube-lengths diminished steadily from 270 to 80 cm. It will be seen that the receiver diaphragm influences the hum pro- foundly. Thus, the circular diaphragm D, developed a mean- frequency of 1,100 ~ or c”’#, judging by the points of minimum primary current, and its pitch zig-zag formed ascending intersections with this line at 95, 125, 155, 185, 215 and 245 cm., approximately, in conformity with the series 5 + 30m cm. The sectored diaphragm D, developed a mean-frequency of A”#, at 920 ~, with ascending intersections nearly in conformity with the series 36m cm. The narrowest diaphragm D, developed a mean-frequency of F”, at 705 ~, and ascending intersections in substantial conformity with the series 33 + 47m cm. It will be observed that there are double breaks in pitch on zig- zag D,. This tendency was found to follow irregularity in the dia- phragm, or in its mounting. Thus, the ordinary standard diaphragm used in all the preceding tests was observed to develop similar double breaks when the clamping screw-cover was slackened, so as to leave the diaphragm somewhat loosely clamped. The pitch zig-zag of D, shows gaps. These gaps seemed to be due to the enfeebled condition of the electromagnetic vibrating sys- tem in the receiver when used with the experimental diaphragm D,. A very marked case of such gaps is presented in Fig. 13, which indicates the frequencies and currents obtained with a particular single-pole telephone receiver, the remainder of the apparatus being unchanged, and the tube-length being steadily reduced from 165 to 80 cm. The line of mean-frequency is at 1,025 ~, and the ascend- ing intersections with this line are formed at points conforming with the series. 28 -+ 32m cm. Only short pieces of the zig-zag were, however, obtainable, and these only with the aid of a condenser in the secondary circuit. The dotted segments RS and TV were obtained with the receiver terminals reversed, and correspond ap- 1908 ] KENNELLY AND UPSON—HUMMING TELEPHONE. 351 proximately to ascending intersections of the series 13 +- 32m cm. Various other modifications of receiver and receiver diaphragm were tried. Loading the diaphragm with a small central mass low- ered the mean humming frequency. By selecting suitabie dia- phragm dimensions, the mean-frequency of the hum could be varied between wide limits. A B a U., a Sr _ Fi aN NOTE FREQUENCY. ete 8 33 ) ' 1 ' ' 1 ! Cc s 8 & i peed | Saas 80 90 100 7) 120 130 140 150 160 TUBE LENGTH - CENTIMETERS. Fic. 13. Discontinuous Frequencies, or Large Gaps in Curves, for Case of Singe-pole Receiver. CURRENT - MILLIAMPERES. Conclusions Directly Derivable from the Experiments.—The fol- lowing more prominent conclusions are indicated by the experiments themselves, independently of any theory: 1. The mean-frequency of the humming-telephone note is deter- mined solely by the receiver diaphragm, and its natural free rate of vibration. 2. The ascending intersections of the frequency zig-zag with the mean-frequency line will be formed approximately at tube-lengths of (¢-++m) v/n, cm. for one connection, and of (4-++ m) v/n, cm. for the other connection, of the receiver; where wv is the velocity of sound in air (33,000 cm. per sec. nearly), m, is the mean fre- quency in cycles per second, and m is any positive integer, within 352 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, the working range of the tube. The constants ¢ and 4 may be modified by the presence of condensers, and other circumstances. 3. The range of pitch variation, and the breaking positions, are determined by the transmitter, and by the reinforcing capability of the system. For systems that are weak, either electrically or acous- tically, the range of pitch, above or below the mean, will be small. 4. The primary current, as measured by a d.c. instrument, is ordinarily a minimum at the mean frequency, and a maximum at a break. 5. Transmitters may be tested for effectiveness, by measuring their hum-extinguishing resistances in the primary or secondary circuit. The tube-length should be such as to produce mean fre- quency if one connection of receiver only is used, but should favor both connections equally, if both connections of receiver are used. ) OUTLINE OF THEORY OF THE HUMMING TELEPHONE. Preliminary Considerations. Simple Orbital Motion and Simple Unretarded Vibration—Let a particle of mass m grammes de- scribe a simple plane circular orbit zab, Fig. 14, about the center ~ Fic. 14. Vector Diagram of Free Undamped Vibration. O. Let the radius Oz =r cm., and let OX be the initial line of reference. At time t= o seconds, let the particle occupy the posi- tion 2; so that its initial radius vector is Oz. Let » be the uniform angular velocity of the particle about the center O, in radians per second. Then, after the lapse of ¢ seconds, the particle will occupy a point in the plane defined by the vector displacement 1908.] KENNELLY AND UPSON—HUMMING TELEPHONE. 353 = rejvt cms. Z (1) where j= \/— 1, and é is the displacement of the particle in cms. from O at the angle wt, measured positively, or counter-clockwise, from the initial line OX. Let the particle be acted upon by a centrally directed elastic force F= — AE=— maé = — mart dynes Z (2) proportional to and opposing the displacement, as represented by the vector OF in Fig. 14. Let there be no other forces except those of inertia, acting on the particle; so that the movement is frictionless. Then the velocity of the particle at any instant ¢ will be v= f= joreit cms./sec. Z (3) The direction of the velocity will, therefore, be perpendicular to the radius vector, or parallel to the instantaneous tangent, as indicated by thé dotted line Ov, 90° ahead of Oz in phase displacement. The acceleration of the particle will be, at any instant f, c= v= E=— writ cms; /sec.= 2": CA) That is, the acceleration will be directed oppositely to the displace- ment. Thus at time fo, represented in Fig. 14, the acceleration will be directed along OY. The virtual reactive force of inertia will be f=— me = — méi= morrdvt dynes Z (5) In Fig. 14, this reactive force of inertia is represented by Of. In order that the circular orbital motion shall be stable, the sum of the forces OF and Of, of elasticity and inertia must be zero; or OF + Of =o dynes /° — mart + mw?reet = 0 dynes Z whence o= VA/m= Va radians/sec. (6) 354 KENNELLY AND UPSON—HUMMING TELEPHONE. [Ju.y 20, If, therefore, the angular velocity of the motion be numerically equal to the square root of elastic force per unit of mass, the orbit will be circular and stable, and Fig. 14 may represent its vector diagram. The particle z rotates about O, at constant radius with uniform angular velocity », and the pair of equilibrating forces OF and Of rotate in synchronism with it. The entire system, Fig 14, may be imagined as pivoted about an axis through O perpendicular to the orbital plane, and spun about this pivot with uniform angular velocity o. By a well known proposition connecting simple harmonic vibra- tion with circular orbital motion, the displacements in the former are the projections of the displacements in the latter, upon a straight line passing through the center of the system. In other words, to every case of simple circular orbital motion in two dimensions corresponds a case of simple harmonic vibration, its projection in a single dimension. Consequently, at time t, we have for the dis- placement in the case of simple vibration, 4 E = rejvt cms. (7) measured along the initial line OX by projection. The real part only of € is retained, and the imaginary part ignored. Similarly, the vibratory velocity will be v= £ = jordvt cms./sec. (8) taking only the real part of the equation, or the projected value along YOX. Again, the vibratory acceleration will be C= — w* rel ot cms./sec.? (Q) retaining only the real or projected part. Similar reasoning ap- plies to the forces of elasticity and inertia. The same equations appear as in the circular orbit case; but only their real, or horizon- tally projected values, are retained. Consequently, we deduce that the vibration of a particle possessing elasticity and inertia without frictional retardation will be stable and self sustained under the condition 1908. | KENNELLY AND. UPSON—HUMMING TELEPHONE. 855 o = 2m = A/m= Va radians/sec. (10) where n is the frequency of the vibration in cycles per second. If, for example, the diaphragm of a telephone receiver had simple elasticity and inertia without frictional retardation, such that the elastic intensity a== 26.87 X 10° dynes per cm. of displace- ment and per gramme mass, then any displacement released would be followed by an indefinitely sustained angular velocity \ w= V 26.87 X 10° = 5,184 radians per second, corresponding to == 825 cycles per second. If the initial displacement were r= 0.01 cm., the corresponding simple circular orbit, Fig. 14, would have a radius of 0.01 cm., an angular velocity of 5,184 radians per second, an orbital velocity of 51.84 cm. per second, and an acceleration of 268,700 cm. per second. If the elastic force A were 1.3435 K 10° dynes per cm. of displace- ment and the effective mass were 0.05 gm., the elastic force OF would be 13,435 dynes, and the centrifugal force Of 13,435 dynes, the two being equal and in complete opposition. Case of Free Vibration Damped and Unreinforced. Spiral Orbital Motion.—In the case of the particle moving about a center, let the motion be retarded by a force f’, proportional to the velocity, defined by the relation f =—Tv=—2myv dynes Z (11) Then the orbital displacement at any time ¢ becomes E=reytiwrt cms, £ (12) The orbital velocity is y= E=1r(—y + jure cms./sec. Z (13) The orbital acceleration is c=v —é == 1(—y + jo) ev? ems./sec.? Z (14) 356 KENNELLY AND UPSON—HUMMING TELEPHONE. [july 20, Each of the above equations defines an equiangular spiral, an in- wardly directed spiral in which the curve makes a constant direction —y-+ jo with the radius vector. The vector diagram for this case is indicated in Fig. 15. Let Fic. 15. Vector Diagram of Free Damped Vibration. z be the position of the particle at any instant. The velocity at this instant will have the vector OV, parallel to the tangent at z, where tan ¢=o/y (15) The acceleration at the same instant will be directed along OY, the angles XOV and VOY being each equal to the supplement of ¢. The virtual force of inertia will be directed along Of. The retard- ing force, opposing the velocity, will be directed along Of’. At any instant the vector sum of the three forces of elasticity, retardation and inertia must be zero. That is, OF + Of’ + Of =o dynes Z ‘ or — mare-y+io)t — 2ymr(—y + jo)eorsot — mr(— y + jo) eyo) t —= 0 dynes Z whence o= Va—y?= Vo,2—y? =o, sin @ radians/sec. (16) where w, is the unretarded angular velocity. That is, the angular velocity of orbital rotation has been reduced by the retardation in the ratio of sin ¢, Fig. 15, and the displacement or radius vector r continually dwindles with time by «7. In the corresponding case of free damped vibration, the above 1908. | KENNELLY AND UPSON—HUMMING TELEPHONE, 357 equations apply ; but their real parts only are taken. In Fig. 15, the projections of the vectors on a straight line through O, are se- lected. The dwindling vibrations of a tuning fork, or the oscillatory discharge of a condenser through a circuit containing resistance and inductance, obey this law. In the last named case, the inductance corresponds to the mass m, the reciprocal of the capacity corresponds to the elastic coefficient A, and the resistance corresponds to the velocity-resisting coefficient [. The condenser-charge, or electric quantity, corresponds to the vibratory displacement, the electric current to the vibratory velocity, the discharging electromotive force to the elastic force OF, the’resistance e.m.f. to Of’, the e.m.f. of self-induction to Of, and the impedance of the discharging circuit to the vector mo, Z¢, or VMA Zo=T/2+ jmo. Case of Retarded Free Vibration Reinforced. Restored Circu- lar Orbit.—In order to sustain stable orbital motion in a particle retarded with a force proportional to the velocity, it is necessary Fic. 16. Vector Diagram of Reinforced Vibration. to supply energy continuously to the particle and to act upon it with a force equal but opposite to the velocity-resisting force. The orbit will then be restored from an inmoving spiral to a simple circle. The displacement, velocity and acceleration of the particle, Fig. 16, will then be severally expressed by equations (1), (2) and (3) ap- plied to Fig. 14. Let OR, Fig. 16, be an outwardly directed force from the center O, the magnitude of OR being some function my(r) of the radius of displacement, and @ the phase ae behind the displace- 358 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, ment, reckoned positively in the direction indicated, or clockwise. The restoring force OR Zé may be analysed into two components OT =OR sin 6, and OS = OR cos @ along the directions OV and OX respectively. The component OT may be called the velocity component, or TJ component, since it acts in the direction of the velocity Ov, and against the retarding force Of’. The component Os may be called the S component, or the new elastic component. It coacts with the elastic force OF that resists displacement. | In order that the circular orbit may be retained, it is necessary and sufficient that the T component of the restoring force shall equilibrate the velocity-resisting force‘Of’; or, if R be the restor- ing force, that R sin 6+ f/=o dynes If the J component should be less than the velocity-resisting force, the system will lose energy. The orbit will spiral inwards until the velocity has been sufficiently diminished to equilibrate the T com- ponent, and permit a stable circular orbit of reduced radius to be re- stored. If, on the contrary, the T component exceeds the velocity- resisting force, the system will accumulate energy, and the orbit will spiral outwards until the radius and velocity of the motion are suffi- cient to restore equilibrium and permit a circular orbit of enlarged” radius to be maintained. In the condition of equilibrium represented in Fig. 16, we have four forces acting on the particle, forming two separate equili- brating pairs; namely, a pair along the displacement vector Oz, which we may call the displacement pair, and a pair perpendicular thereto, which we may call the velocity pair. Both these pairs rotate together at some uniform angular velocity w, which will in general differ from that which would hold for unretarded motion w,, as in Fig. 14, or from that which would hold for retarded unreinforced motion, as in Fig. 15. Considering the displacement pair, the first member is the salah force OF, modified by the new elastic force OS, to OF’, Fig. 16. The new virtual force of inertia is Of. Consequently OF’ + Of =o dynes 1908. ] KENNELLY AND UPSON—HUMMING TELEPHONE. 359 or — mareet +. my(r) cosd et + mw?reiot =o dynes Z whence w= Va—cos6- x(r)/r radians/sec. (17) Considering the velocity pair, the first member is Of =— Tv =— 2myv = — j2myord +t dynes Z The second member is the T component: OT =—jmx(r) sind - vt dynes Z For equilibrium : Of’ + OT=o0 or — jamyoreet — jmyx(r) sind - 4t—=o From which x(r) sin 6=— 2ryo dynes (18) and ‘ ear o= Vo," + y? cot? 6+ y cot 6 radians/sec. (19) It follows that , the new angular velocity under reinforcement, is independent of the force function R= mzx(r), and depends only on the natural angular velocity w,, the phase retardation 6 of the re- storing force and the magnitude of the damping coefficient y. Some curves of w as a function of @ for four particular values of IT be- tween 50 and 500 dynes per cm. per sec. ; 7. e., of y between 500 and 5,000 dynes per cm. per sec. and per gm., are given in Fig. 17. It _ may be seen that for all values of the damping, ow, for @=270°. That is, the angular velocity of reinforced motion is the same as that of unretarded motion when the restoring force is applied at 270° of phase lag, or exactly in phase with the velocity, as seen in Fig. 16. If the phase retardation is between 180° and 270°, the new angular velocity will be greater than the natural angular velocity w,; but if @ is between 270° and 360°, must be less than oy. Applying the above principle to the corresponding case of rein- forced vibration, by taking the projections or real parts of the rotat- 360 KENNELLY AND UPSON—HUMMING TELEPHONE. {july 20, ing vectors, it follows that if any automatically reinforced vibrating system, such as an electromagnetic bell, electromagnetic tuning fork, or humming telephone, is propelled by an elastic force proportional to the displacement, reinforced by a cyclic force some function of the displacement, and damped by a force proportional to the velocity, it is subject to equations (17), (18) and (19) which appear to be new. In the series of measurements on the humming telephone above Hi : COW \ ‘2 2 00F* eee E 2 RN 4 éad : PANE 900 7 2 . \— noe ‘s u + J ; g a . \\ i. 0. DOs \J ~,' a8 - J et gS She “4 N 8 6 Degrees of Lag. Fic. 17. Reinforced Frequency in Relation to the Phase of the Reinforcement. 270 outlined, the force function R—my(r) was not measured. The restoring electromagnetic force on the receiver diaphragm, due to the action of the transmitter, will manifestly diminish when the tube- length is increased. For a fixed tube-length, moreover, it cannot increase indefinitely in simple proportion to the displacement of the diaphragm, or to its amplitude of vibration. If we assume pro- visionally that R increases as the square root of the amplitude of x908,] KENNELLY AND UPSON—HUMMING TELEPHONE. 361 receiver-diaphragm vibration; so that for a fixed tube-length, R=bmyr; or x(r) ==bV7; where b is the numerical constant 1.036 X 10° dynes per gm. and per V/em.; then for the example already considered, if f= 100; or y= 1,000, we find: The displacement r= 0.01 cm. when 6 = 270°. The reinforced angular velocity is » = 5,184 radians per second; n= 825 ~. The maximum cyclic values of the vibratory— velocity v= 51.84 cm. per sec. acceleration c == 268,740 cm. per sec.? damping force Of’== 5,184 dynes. restoring force OT = 5,184 dynes. elastic force OF’ = 13,435 dynes. inertia force Of = 13,435 dynes. As the phase 6 of reinforcement changes from 180° to 360°, the line of y= 1,000 in Fig. 17 shows the change in frequency; while the dotted line indicates the computed amplitude of vibration, which reaches a maximum near 280°. According to the theory, therefore, if the phase of the displace- ment is 270° behind the displacement of the receiver diaphragm, the reinforced frequency coincides with the natural frequency. This condition is substantially borne out in all of the observations. For example, in Fig. 2, taking the pitch line No. 1, with a natural fre- quency of n, = 825 ~ and a sound-velocity in air of 33,000 cm. per sec., the wave-length = 33,000/825 = 40 cm. corresponding to, 360° of phase. A lag of 270° would be represented by 30 cm.; so that we should expect the reinforced frequency to be 825 ~ at 30 cm. of tube-length, and at every 40 cm. beyond; i. e., in accordance with the series 30 + 4om, as was substantially observed. Moreover, by reversing the receiver terminals, the phase of the reinforcement is necessarily changed 180°; so that with this change of connec- tion, 270° of phase lag would be altered to 90° of phase lag, or 10 cm. of tube-length. The natural frequency of 825 ~ should then occur in conformity with the series 10 + 40m cm., as was substan- tially observed. o 362 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, When the phase retardation 6 of the restoring force (Fig. 16) is less than 270°, we should expect, according to the theory, that the pitch should rise; because the elastic resilience of the diaphragm is virtually increased by the OS component of the new force, and when 6 > 270°, on the contrary, the pitch should fall. This was always the case in the observations. We have to bear in mind, however, that with any given tube-length, an alteration of pitch involves a change of wave-length, and therefore a change of phase in transmission through the air-column, besides any electrical change in phase due to change in current frequency. In Figs. 3, 4 and 6, the sloping dotted lines are drawn to indicate constant acoustic phase retardation of 270° for all of the frequencies within the range considered. Taking, for instance, Fig. 6, the break at P occurred 103° in phase from the dotted line of 270°, and the return at S occurred 77° in phase from the dotted line. According to the theory, assuming no electric change of phase, each of these angles should be something less than 90°, since the phase retardation must be something more than 180° on the side of increasing pitch. The discrepancy here is not serious; for the mean of the two angles is 90°. At T and W, however, the corresponding angles are 153° and 119°, with a mean of 136°, which should be something less than 90°, a greater diver- gence from the theory than observation errors can explain. While, therefore, the theory accounts for all of the experimental results in a general way, it can only be regarded as a first approximation. For example, it is possible that superposed harmonic currents might have to be considered; or that in estimating the damping forces, the in- clusion of higher powers of the velocity than the first might be necessary. Setting aside unexplained deviations, as the tube-length is short- ened from a point of 6== 270°, the phase retardation of the electro- magnetic reinforcement on the receiver diaphragm is diminished. This causes the pitch to rise, and incidentally readjusts the phase change to a lower value than if the pitch were kept steady. The amplitude of vibration diminishes until the diaphragm suddenly selects a lower pitch for the same tube-length, to which the ampli- tude will be greater. In other words, the receiver diaphragm auto- matically seeks to maintain the greatest amplitude that the condi- 1908. ] KENNELLY AND UPSON—HUMMING TELEPHONE. 363 tions of reinforcement will permit. If a lower tone, with a phase lag 6 more than 270°, will give more amplitude than the higher note to which it has been driven, with 6 less than 270°, it will break pitch downwards. This process will continue down to the first wave-length of tube, or 40 cm. in the case examined. For connec- tion J of the receiver, it can break to no lower note after passing 270°, and the tone will rise to such a pitch that the amplitude be- comes insufficient to excite the transmitter, so that silence should ensue at or near the length 12 cm., as actually observed in Fig. 3. The curve J of frequency between I2 and 50 cm. accords fairly well with the curve y = 1,000 in Fig. 17. r 46.4 Re t, le 0.0765 0.028 Fic. 18. FIG. 19. Fic. 18. Diagram of Electrical Connections with Step-up Induction Coil. Fic. 19. Equivalent Diagram of Connections, with Level Induction Coil. Btfwu-n) syr/lewls-%) Za 24 jw O0002TT 2.76 +/w0.0002rF AR, #32476 9.000277 14.86 + jw 0.00/7/7 Fic. 20. Fic. 21. Fics. 20 AND 21. Equivalent Conductive Connections with Level Induction Coil and Alternating E.M.F. With reference to the influence of capacity in the secondary cir- cuit, Figs. 18 to 21 show the successive steps by which the secondary circuit may be treated as a conductive branch of the primary circuit. Using the constants given in Table I., ignoring any capacity exist- ing between the windings of the coils, and assuming that the effect of the transmitter in the primary circuit is equivalent to an alter- nating e.m.f. e, working through a transmitter resistance R, of 50 ohms, we find a coupling coefficient for the coil of K 0.937, and 364 KENNELLY AND UPSON—HUMMING TELEPHONE. [July 20, an inductance ratio S 0.0575 between primary and secondary windings. Proceeding in this way, the following table has been arrived at, giving the conductances which when multiplied by the equivalent transmitter e.m.f. yield the current strength in the sec- ondary circuit of Fig. 21. Taste ITI. : Angular Velocit bao. Frequency cen per | padiann per Second. | CAPM. In Seegndary | Condzernes me 637 4,000 “ 0.009 /23° 796s 5,000 “ 0.0087 /17° 956 6,000 oc 0.0093 /12° 637 4,000 0.2 0.0054 \140° 796 5,000 0.2 0.0095 \123° 956 6,000 0.2 O.II \115° Although the assumptions employed do not anticipate a high degree of accuracy in the conclusions above tabulated, yet we may safely infer that when no condenser is used in the secondary circuit (uf. = «), the secondary current will lead the impressed primary e.m.f. by a small angle, and this current will have substantially the same strength and phase for all frequencies between 600 ~ and 1,000 ~. When, however, a condenser of 0.2 pf. is inserted in the secondary circuit, the current in the receiver will be advanced in phase about 110° or nearly a third of a cycle; while the strength of this current will be considerably greater at the higher frequencies than at the lower frequencies. Since the total lag in phase of the restoring electromagnetic force behind the displacement of the receiver diaphragm includes (1) the electric current lag; (2) any hysteretic electromagnetic lag in the receiver cores; (3) any mechanical inertia lag of the transmitter diaphragm; (4) the acoustic lag in the air column of the tube; it follows that the total lag with a condenser of 0.2 wf. should be about 110° less than with short-circuited condenser; while the higher fre- quency notes should be favored, and the lower frequency notes dis- favored. Fig. 9 shows that both these effects took place, the acous- tic lag had to be increased by about 12 cm., or about 110°, in order to produce mean frequency, and compensate for the current lead. 1908,] KENNELLY AND UPSON—HUMMING TELEPHONE. 865 Also the range of frequency is moved bodily towards higher notes. All of the experimental series of observations appear to be ac- counted for and explained by the above theory to a first approxima- tion ; although in matters of quantitative detail there remains much room for further development. In conclusion, the authors desire to express their indebtedness to the Western Electric Co. for the loan of apparatus used in the tests. PROC. AMER. PHIL. SOC., XLVII. 189 X, PRINTED OCTOBER 3, 1908, ON THE AFTER-IMAGES OF SUBLIMINALLY COLORED STIMULI. By EDWARD BRADFORD TITCHENER ann WILLIAM HENRY PYLE. (Received July 23, 1908.) We attempt, in the present paper, to answer the question whether a subliminally colored stimulus may arouse a colored, negative or complementary after-image. This question has been answered in the affirmative both for direct and for indirect vision, and in indirect vision for all three of the retinal zones. Our own experiments, on the other hand, have led us to answer it in the negative. Provided that the subliminally colored stimulus appears on a neutral (black, gray or white) background, and provided that the retina is achro- matically adapted, we find no trace of the colored after-image in either direct or indirect vision, with either light or dark adaptation. Previous EXPERIMENTS. 1. Direct Vision—In a paper entitled Das Anpassungsproblem in der Physiologie der Gegenwart (1904), A. Tschermak compares the course of excitation in the retina with the effects produced by the constant current in a nerve-muscle preparation. The passage is as follows: “ Haben wir doch gerade in der Anwendung des constanten Stromes auf Nerv und Muskel ein vorziigliches didaktisches Mittel, um die Grundbegriffe der allgemeinen Reiz- und Adaptationslehre zu veranschaulichen und einzupragen. Am besten demonstrieren wir als Gegenstiick zugleich die Wirkung eines miassig satten Farbglases auf das Auge: die Phase der Reizwirkung, individuell verschieden lang, und dadurch erinnernd an die verschiedenrasche Adaptation des Praeparates vom Warmfrosch und Kalt- frosch an den constanten Strom—weiterhin das Stadium der vollendeten Adaptation, endlich den gegensinnigen Oeceffnungseffect. Nicht minder lehrreich ist die Parallele des subjectiven und des objectiven Erscheinungs- gebietes fiir das Phaenomen des Einschleichens d. h. des Ausbleibens einer sinnfalligen Reizwirkung, wenn der Reiz so langsam anwachst, dass das Adaptationsvermogen folgen kann — gleichwohl hat auch nunmehr Wegfall 366 1908.] OF SUBLIMINALLY COLORED STIMULI. 367 des ‘ Reizes’ eine gegensinnige Oeffnungswirkung. Analoges gilt vom Aus- schleichen, also vom Ausbleiben eines sinnfalligen Oeffnungseffectes. Zum optischen Versuche schiebt man zweckmassig eine schwach tingierte Glas- _platte vor die andere oder beniitzt einen Keil farbigen Glases.”* The observation here briefly mentioned was apparently made in light-adaptation. The observer, we may suppose, looked through a vertical slit in a cardboard screen towards a window. The thin end of the colored glass wedge, viewed through the slit, appeared colorless. The wedge itself was slowly pushed forward — so slowly that progressive adaptation prevented its color from being per- ceived. Presently the observer turned his eye to the cardboard screen, and there saw the negative colored after-image, the “ gegen- sinnige Oeffnungswirkung ” that followed the “ Einschleichen des Reizes.” ? 2. Indirect Vision—lIn the Studies from the Psychological Laboratory of Mount Holyoke College for 1905, Miss G. M. Fernald reports the arousal of colored after-images in the peripheral or black-white zone o. the retina. “A further point worth mention- ing ’—so the passage runs—“ is the fact that, in the case of several colors, exposure, beyoud the limits where any color is seen, is fol- lowed by a very clear [colored] after-image. This was repeatedly found to be true with red, orange, green and blue and often with yellow [stimuli]. This after-image for the first three and for yel- low was blue, and for blue a very clear yellow. This may explain the ‘ gegenfarbige ’’ zone found by Hellpach in his dark-room work, as under those conditions there would have been no way of telling whether the color came exactly at the time of exposure or immedi- ately afterwards.”* No further details are given. * Archives des sciences biologiques, XI., Supplément (Festschrift for Pro- fessor J. P. Pavloff), 82 f. * The procedure is sketched by H. Abels, Zeits. f. Psychol., XLV., 1907, 86. “Man kann .. . einen schwach gefarbten Glaskeil so langsam vor das Auge schieben, von der Kante gegen den Riicken fortschreitend, dass iiberhaupt keine Farbenempfindung zustande kommt; und dennoch haben wir bei plétzlichem Entfernen desselben und Betrachten einer indifferent gefarbten Flache die deutliche Empfindung der komplementaren Farbe.” Abels is here quoting a conversation with Tschermak; there is no evidence that he himself performed the experiment. 3“ The Effect of the Brightness of Background on the Extent of the Color Fields and on the Color Tone in Peripheral Vision,” Psychol. Review, XII., November, 1905, 405. 368 TITCHENER AND PYLE—ON THE AFTER-IMAGES [July 23, These observations would, no doubt, have been repeated, and their interpretation discussed by other experimenters, had not Baird published, earlier in the same year, his study of the color sensitivity of the peripheral retina. “There seems to be no doubt,” Baird had~ written, “that Hellpach’s zone of complementariness,is an artifact, and that its discovery is wholly due to the experimenter’s failure to avoid retinal fatigue [chromatic adaptation] in his explorations.” * Nevertheless, one of the present writers (TI) made in 1906 a fairly long series of campimetrical observations (some 200 in all) with the view of testing Miss Fernald’s conclusion. The colored stimuli ‘were Hering papers, R, Y, G and B; the backgrounds were white, neutral gray and black. In no case was “ exposure, beyond the lim- its where any color is seen,” followed by a colored after-image, clear or obscure. All four colors, if they gave an after-image at all, gave a colorless image, indistinguishable from the after-images of gray stimuli—as these gray stimuli themselves were indistinguish- able from the colored papers. It therefore seemed probable—in- deed, it seemed practically certain—that the Mount Holyoke results were due to a defect of method. Since Baird’s disproof of the “oegenfarbige Zone”’ was deemed complete and final, the Cornell observations were not published. . However, in the following year, 1907, a second paper from the Mount Holyoke laboratory reported the same phenomenon. “ At the extreme periphery it sometimes happened: (a) that a stimulus which was clearly seen produced no after-image. . . . (b) On the other hand there were 118 cases in which a subliminal stimulus pro- duced an after-image which was perfectly distinct in color. ... That this somewhat unusual result was not the outcome of imag- ination or suggestion seems proved by the fact that these invisible colors gave rise to their appropriate after-images.”*® The authors, the Misses H. B. Thompson and K. Gordon, found no indication of Hellpach’s zone of complementarism. They refer the i images to the enhancing influence of a light background. *jJ. W. Baird, “ The Color Sensitivity of the Peripheral Retina,” Carnegie Institution of Washington, Publication No. 20, May, 1905, 73. *“A Study of After-Images on the Peripheral Retina,” Psychol. Review, XIV., March, 1907, 126 f., 129 f. , } 1908. ] OF SUBLIMINALLY COLORED STIMULI. , 369 Again, in 1908, in a continuation of her former study, Miss Fernald writes: ‘“ In agreement with the observations already made in our first paper, and later in the work of Miss Thompson and Miss Gordon, our results show that in many cases a characteristic colored after-image follows an unperceived color stimulus. In general this after-image is perfectly clear and distinct. . . . That the phenomena here described are genuine after-images is shown by the fact that the color is in every case the color complementary to the stimulus as [it would be] perceived either in central or in peripheral vision, although the observer was kept in complete ignorance concerning the nature of the stimuli employed, and so had no clew as to what after-image was to be expected in cases in which the [color of the] stimulus was not seen. Moreover, gray and white, though fre- quently used as stimuli, were never followed by colored after- images.” ® Hellpach here drops out of sight altogether, while the range of the subliminally aroused after-image is extended, from “the extreme periphery,” to include both the B~Y and the R-G zones, New EXPERIMENTS. I. Direct Vision: (a) Light-Adaptation. Experiment I.: The Glass Wedge——We wished to begin our own experiments by repeating Tschermak’s observation with the faintly colored glass wedge. However, the difficulty of finding a suitable glass proved to be so great that this Exp. I. was, as a mat- ter of fact, performed last of all. After many delays we were able, through the kind assistance of Professor J. A. Brashear, to secure a wedge of light blue glass,.5 by 20.5 cm., the thin end of which was almost colorless in clear daylight. Although the color might well have been still fainter, we found it possible, with an observation- slit of 22 by 5 mm., and with a white muslin screen stretched be- tween the glass wedge and the white-screened windows from which our illumination was derived, to take observations of 2 to 5 min. duration, in which the wedge was moved, for the practised observ- ers, from 1.5 to 4 cm., and for the unpractised ‘from 5 to 10 cm. * Studies from the Bryn Mawr College Laboratory: The Effect of the Brightness of Background on the Appearance of Color Stimuli in Peripheral Vision,” Psychol. Review, XV., January, 1908, 33 ff. 370 TITCHENER AND PYLE—ON THE AFTER-IMAGES [julya3, We made no long series of tests, since the question at issue had already been answered, so far as we could answer it, by the follow- ing Exps. II—V. The experiments were, however, carefully con- ducted. The work was done in a long gray-tinted light-optics room, with achromatic adaptation ; the observers were the writers (T, P), Mr. L. R. Geissler (G), assistant in psychology, and two unprac- tised students, Mrs. G. L. de Ollogni and Mr. E. M. Stevens; and the experimenter had acquired great skill, from Exps. II. and IV., in moving the wedge slowly and steadily forward. In general, the stimulus-background was black, and the field for the projection of the after-image was white, though these relations were occasionally changed. As we had expected, there was no trace of color in the after- image; this result was uniform. In control experiments, in which (after a period for the recovery of the eye) the glass was exposed for 30 sec. at the point finally reached in the adaptation experiments, the after-image showed a brief period of dirty orange or brownish yellow, followed by gray. Experiment II.: The Marbe Color Mixer—rThe observations with Tschermak’s wedge could not, in any case, be regarded as more than preliminary. For systematic work we employed, first, the Marbe color mixer, which permits the change of a colored sector during rotation of its discs, and thus gives scope for progressive adaptation. The observer, head in rest, was seated at a distance of I m. from a black cardboard screen. The rotating discs were observed through a circular opening, 2 cm. in diameter, cut in the screen at the level of the eyes. The observation was monocular, and was continued for 5 to 7 min. The discs were made up of white, with a sector of colored paper (Zimmermann R, Y, G, B, V); the color at the outset was subliminal for the achromatically light-adapted eye, and was gradually increased in amount as the observation pro- ceeded. The after-image was projected upon a fixation-point marked on a white cardboard dropped in front of the black screen.* "For comparative purposes, a few observations were taken with a gray screen, and with projection upon a black or gray background. Nothing new resulted. 1908.] OF SUBLIMINALLY COLORED STIMULI. 371 The regular observers were T, P, G, and Mr. T. Nakashima, gradu- ate scholar in psychology (N). A few observations were secured from Professor I. M. Bentley (B), and from an unpractised ob- server, Mr. H. J. Bool; single observations were made by several visitors to the laboratory. In intention, the procedure was without knowledge. In practice, the experimenter found it impossible, in the early stages of the work, to regulate the size of the colored sector in precise accordance with the course of adaptation. The observer was therefore in- structed to tap on the table with a pencil whenever he perceived a color in the stimulus. If a tap was given, the experimenter ran the colored sector back through five or ten degrees, and continued the experiment from that point. The results of these interrupted observations varied, according to the frequency of the taps and the insistence of the color in the stimulus. The following are typical records. A. No Color Seen in Stimulus. Observer. Color in Disc. After-image. Duration of Obs. T 205° B Gray 7 min. 180° V Gray 6 min. P 120° G Gray 5 min. 140° V [Gray \ 5 min. 15 sec. G 135° R Gray 6 min. B 190° B Gray 6 min. After a period for recovery, the stimuli were exposed at their final color-strength for 30 sec., and the after-image was projected as before. The results, in the above instances, were as follows: Observer. Color Seen. After-image. fT Blue Brownish yellow Bluish violet Dirty olive yellow PF Green Pink Bluish violet Dingy yellow G Red Gray B Blue Clear yellow B. Color Seen in Stimulus. Observer. Color in Disc. After-image. Duration of Obs. T 140° G Gray 5 min. G 120° Y Dark blue \ 5 min. 220° B ? Orangish 7 min. N 155° R Gray 7 min. 130° Y Blue 6 min. 372 TITCHENER AND PYLE—ON THE AFTER-IMAGES jjuly23, The control experiments, with 30 sec. exposure, gave the results: Observer. Color Seen. After image. 2p Green Purple G Yellow Dark blue Blue Yellow N Pink ? Violet Yellow Blue The general results of these experiments may be summed up in the following propositions. 1. With every one of our observers, regular and casual, we have been able to raise a color-component in the stimulus from a sub- liminal to a normally supraliminal value, while the stimulus ap- peared throughout as gray. In no instance of this kind has the observer found the complementary color in the after-image. Our results thus stand in direct opposition to the observation of Tschermak. 2. There are, however, marked individual differences among the observers. In the 7 min. which represented the limit of our obser- vations, it was difficult, with G and N, to increase the color-com- ponent, without detection, to a normally supraliminal amount: with T, P and B there was no,such, difficulty. The control images, on the other hand, were obtained most readily from T and P. The observer N is of the subjective type, and is often misled by an “expected” or “imagined” color. Thus a disc containing 175° G was seen as B with a rim of Y; the after-image, after 6 min., was a Y of irregular form, larger than the stimulus. We recur to these “imagined” colors later. The remaining observers were of a distinctly objective type. 3. There were also, as might be expected, marked differences in the “coloring power” of the Zimmermann papers. Experiments of the form A were easiest with B, less easy with V; then follow in order R, G, Y. The last-mentioned color, indeed, gave results only with entirely naive and unpractised observers. The R and G, when seen as color, usually appeared first as Y. 4. As a rule, the after-images, whether colored or gray, devel- oped very slowly. The gray images, in particular, might appear only after a blank interval of 15 to 30 sec. They usually showed 1908 ] OF SUBLIMINALLY COLORED STIMULI. 378 two stages, dark and light. The colored images, both of the regular and of the control experiments, passed off as gray. Experiment III.: The Color Mixer with Unchanged Discs.—So far we have followed and systematised Tschermak’s method; the amount of color in the stimulus has increased, during the single observation, and has been compensated by a progressive adaptation. In the present experiments the amount of color in the discs is in- creased from subliminal to normally supraliminal, step by step, in successive observations. The rotating discs were observed, as before, through a circular opening in a black or neutral gray screen. The discs themselves were made up of neutral gray (identical with that of the screen), with a colored sector (Hering R, Y, G, B). The stimulus was fixated for I min., and the after-image was projected upon a neutral gray or black background. P, G and N served as regular observers: a few observations were also taken from B and T. The following are typical results. Color in Observer. Color in Disc. Color Seen, After-image. G 4°G None None 10° G Green None 14° G Green Pinkish N 9° B None None 12° B None None 20° B ? Pinkish None 50° B Blue Yellow tng 6° R ? Ruddy None 1o° R Red None 30° R Red Green T ae | None None 12°. Y ? Yellowish None Ds ait Yellow Dark blue In the above observations, the black screen and the neutral gray back- ground were employed. Other arrangements of screen and background gave similar results. In no case was a colored after-image obtained from a sublimi- nally colored stimulus. On the contrary, the image appeared only when the stimulus-color was distinctly supraliminal. 374 TITCHENER AND PYLE—ON THE AFTER-IMAGES july 23, (b) Dark-Adaptation. Experiment IV.: The Glass Wedge.—bBesides furnishing the light blue wedge of Exp. I., Professor Brashear supplied us with smaller and more highly colored wedges of claret, red, orange, green and blue glass. With these, or with combinations of them, we proceeded as follows. A sheet of ground glass was inserted in the Hering window of a large dark-room: the width of the strip could be regulated at will. Some 2.50 m. before the window was a table, on which stood a large screen of white cardboard. Immediately behind a vertical slit in this screen (3 by 25 mm.) lay a grooved strip of wood, in which the wedge or wedges could be moved. Observations were made in dark-adaptation. The thick end of the wedge was first shown; it appeared as black or as dark gray. The wedge was then moved along, very slowly: if the observer saw its color, he tapped with a pencil, and the experimenter withdrew it a trifle, to start again after a few seconds. At a-given signal, the observer looked away from the slit to the cardboard screen, or to a black surface directly below the screen, and watched the development of the after- image. The regular observers were T, P, G and N; a few observa- tions were also made by B. Owing to the difficulty of procuring the large glass wedge of Exp. I., these dark-room observations were the first taken. And, in our desire to do justice to Tschermak’s method, we spent more time and trouble upon them than we like to recall. The observer’s head was fixed securely in a head-rest; the height of the screen was carefully adjusted; generous time was allowed for adaptation; the admission of light was rigorously controlled, beforehand, by the experimenter ; the uniform movement of the wedge was assiduously practised. We were rewarded, however, by the unequivocal charac- ter of the results. Though observation might be continued for 5 min.; though during this period the observer might tap his glimpse of color no less than seven times; and though in the control experi- ments, with immediate observation of the part of the wedge finally exposed, a good complementary after-image might be obtained in 1908 ] OF SUBLIMINALLY COLORED STIMULI. 375 20 sec.: we did not once, in the course of the principal experiments, obtain a record of color in the after-image. Sometimes the after- image failed to appear at all; more often it appeared, and obstinately remained, as gray. The duration of a single observation varied between the limits of 2 min. 30 sec. and 5 min.; most of the exposures were about 3 min. The number of taps varied from 0 to 7; the average for all observers was 4. The color was thus much more insistent than in Exp. I]. — partly, no doubt, because the range of possible movement was only about one-third of that allowed by the Marbe mixer. In the control experiments, T and P obtained the colored after-image fairly easily; G, N’and B often failed to secure it. Experiment V.: Colored Papers.—These observations were also made in the dark-room and with dark-adaptation. A number of Milton-Bradley colored papers, 4 by 8 cm., were pasted upon white, neutral gray and black grounds. The Hering window was so ad- justed that, for the experimenter, the color of the particular paper exposed was just subliminal. The observers (7, P, G, N and occa- sionally B) fixated the colored strip at a distance of 1 m. for 40 sec., and projected the after-image upon a white, neutral gray or black surface. All possible combinations of stimulus-ground and projection-ground were employed. The observer was instructed to report the quality of the stimulus as it appeared at first fixation, and to mention any qualitative change that it might undergo in the course of an observation. In most cases the color was subliminal ; and the subliminally colored stimulus never gave a colored after-image. In the cases in which the color ‘of the strip was seen, the after-image was sometimes colored, some- times gray. The direct judgment of color under these conditions is extremely difficult, and the observer is sorely tempted to avail himself of secondary criteria—brightness, velvetiness, depth, sMimmer, etc. An observer of the objective type soon learns, however, to distinguish between vision and imagination: “I can see nothing,” he will say, “but I should guess that it is red” or what not. The guesses were confined—probably from the analogy of the immediately preced- ing Exp. IJI—to the four colors R, Y, G, B; and, as we had the full set of Milton-Bradley papers at our disposal, they were more 376 TITCHENER AND PYLE—ON THE AFTER-IMAGES jjuly23, often wrong than right.6 Their influence upon the after-image ap- peared only in the case of the subjective observer N. Thus, R seen on W was judged by N to be “red or blue”; and the after-image, also on W, was a large irregular disc of yellow. R seen on Bk was judged to be “ bluish”; and the after-image, on gray, was green- blue with a vague yellow rim. B seen on W was judged “ blue or red” ; and the after-image, on gray, was red above and blue below, with a yellow patch between. It is noteworthy that here, as in Exp. II., after-images of the “ supposed ” or “ imagined ” color invariably differed in form and size from those of the true color. The ob- server did not realise the significance of this difference, though in time he would doubtless have learned to use it as a secondary criterion. II. Indirect Vision. We have already mentioned the experiments made by T in 1906 with the view of testing the conclusions of Miss Fernald’s first paper. The observations were rigorously confined to the Bk-W zone, and their outcome was definitely negative. In the meantime, however, the arousal of a colored after-image by a subliminally colored stimulus had been maintained for both the B-Y and the R-G zones. Unsystematic observations made in the Cornell Labora- | tory failed to confirm this result. It seemed worth while, however, to obtain further testimony; and Professor J. W. Baird, of the University of Illinois, very kindly consented to investigate the subject.® *One of the observers remarked that the experiments showed—what he had never fully understood before—how it is that a case of partial color- blindness may remain undetected both by the color-blind person himself and by the normal persons in his surroundings. In principle, the remark was correct enough; byt in practice the observer would have had to revise and extend his criteria very considerably. ° All the observations in indirect vision mentioned in this paper were carried out with light-adaptation. Peripheral after-images in dark-adapta- tion are practically non-existent. In op. cit., 56 £., Baird writes: “ After- images—in the ordinary sense of the term—were almost invariably absent from our experiments. They were reported in less than one per cent. of our exposures; and when they did occur, they were aroused by the stimula- tion of paracentral, never of peripheral, regions of the retina.” And in a personal letter he adds: “ There is an interesting difference of function in 1908.] OF SUBLIMINALLY COLORED STIMULI. 377 ‘The experiments were carried out by means of a simplified form of the Zimmermann perimeter, which permitted an accurate record of the degree of eccentricity at which the stimulus was exposed. Exploration was confined to the horizontal nasal meridian of each eye. The stimulus was a beam of light from an electric (16 c. p.) lamp, transmitted through appropriate combinations of gelatines and colored glasses; the colors employed were (non-equated) B and Y, R and G. Six of the most reliable laboratory students’ acted as observers, and Professor Baird had personal charge of the entire work, The after-images were projected upon white, gray and black grounds. The experiments proper were preceded by a careful de- termination of the outermost limits of color vision for the stimuli used, and all pains were taken to avoid chromatic adaptation. The following may serve as a sample of method and results. Determination of Outermost Limits of Blue Vision: Observer Bu. Right Eye. Preliminary. Series r. 90°—75° Nothing 72°-58° Black 70°-55° Dark gray 56°—50° Bluish 50°-45° Blitish 48°- Blue 40°—- ~~ Bilue Series 2. Series 3. 75°-63° Black 73°-61° Very dark gray 61°-53° Bluish 50°- Bluish 51°— Blue Outermost limit (bluish or blue): 61°. Left Eye.™ 90°-65° Nothing 62°—so° Black 60°-40° Dark gray 48°-44° Bluish 35°- _—_— Bluish to blue 42°- —- Blue 60°—48° Black 58°-44° Black 46°—- — Bluish 42°- _— Bluish Outermost limit (bluish or blue) : 48°. the peripheral retina in light-adaptation and in dark-adaptation. In the latter case, after-images—both uncolored and colored—are faint or wholly lacking. In the former case they are readily perceptible. Yet even in light-adaptation they are less perceptible than are the primary images aroused by the given stimuli.” * The Misses M. Miller, A.B., and B. Scoggin: and Messrs. C. B. Busey, A.B., R. Garrett, O. L. Herndon and A. C. Schertz, A.B. 4 The visual acuity of the left eye was less than that of the right. 378 TITCHENER AND PYLE—ON THE AFTER-IMAGES [july 23, Perimetrical Experiments. Stimulus. Duration. Perception. n After-image. 90° Right 30 sec. Nothing None 90° Left 30 sec. Nothing None 80° Right, 30 sec. Nothing None 80° Left 30 sec. Nothing None 70° Right 40 sec. Dark gray None 70° Left 40 sec. Nothing None 60° Right 40 sec. Bluish, then black None 60° Left 40 sec. Gray None 50° Right 40 sec. Dark bluish, then gray Yellowish, then gray 50° Left 40 sec. Trace of bluish, then gray Gray It does not seem necessary to print the full set of results, though the data are at the disposal of anyone who may wish to consult them. The net outcome of the enquiry, in Professor Baird’s words, is as follows: “In not a single instance did any stimulus give a colored after-image at a retinal region where it gave an uncolored image,” 1. e., where it was seen as black or gray. He proceeds: “T have tried every varidtion of the conditions (with exclusion of chromatic adaptation) which my ingenuity could devise; and the result is in every instance negative, so far as the contention of the Misses Fernald, Thompson and Gordon is concerned.” CRITICISM AND INTERPRETATION. 1. The positive outcome of Tschermak’s observations with the glass wedge must, in our opinion, be explained by the prepossession of the-observer and the roughness of the method employed. Had Tschermak been in doubt as regards the after-image, he would have had recourse to a more refined instrument, as the Marbe color-mixer. And had he adopted a better method, we cannot doubt, on our side, that the outcome of his observations would have been negative. We may, perhaps, venture to express the hope that he will now submit his hypothesis to a stricter test. ’ 2. It is less easy to account for the peripheral results. The experimentum crucis, in positive regard, would seem to be the pro- duction of a colored after-image, in the achromatically adapted eye, at a point lying well beyond the limits of B-Y vision. It must be remembered that in all liminal determinations an unnoticed varia- tion in physical or physiological conditions, or in the conditions of 1908. ] OF SUBLIMINALLY COLORED STIMULI. 379 attention, may lead to a serious variation of numerical result. It is, for instance, exceedingly doubtful if any but the most careful and most highly practised observers can maintain their fixation so accurately as to ensure a precise localisation of the retinal area affected by a given stimulus. Moreover, we are here dealing with a retinal function which tails. off gradually from center to periph- ery: so that a very slight shift of regard, or a momentary lapse of attention, or a minimal change in adaptation or in illumination may be enough to vitiate an-observation. An illustration may be taken from the records of the observer Bu., quoted above. The outermost limit of B-vision, in the left eye, was determined as 48°. Nevertheless, the observer reported, in the experiments proper, a “trace of bluish, then gray ” with the stimulus at 50°. There was no colored after-image. But suppose a tinge of blue-adaptation: then we might have had a perception of gray, and a yellow after- image; and we should still have been, apparently, beyond the limit of B-Y vision. It was only the care taken to avoid chromatic adaptation that prevented the positive result. It is, of course, precisely this crucial experiment which is de- scribed affirmatively by Miss Fernald in 1905,*? and which came out negatively in 7’s experiments of 1906. The question then arises as to the accuracy of determination of the zonal limits. And on this point we may quote specimen results from Miss Fernald’s tables. 1. R stimulus on light gray background.* 10°-73° Stimulus uniformly seen as red. 74.5° No color seen. 76° Red seen in two observations. 80° Red seen in four, no color seen in two observations. 82.5° No color seen. 84° No color seen. *®We follow the phrasing of the Psychol. Review of 1905: “ Expasure, beyond the limits where any color is seen, is followed by a very clear after- image.” In the Journ. Philos., Psychol. & Sci. Meth., iii., 1906, 352 (Report of Sec. of N. Y. Acad. of Sciences), the report reads: “ After-images were perceived, almost without exception, as far out as any color could be dis- tinguished, and in many cases were clearly seen though the stimulus color was not recognised.” * Psychol. Review, XII., 408. Italics ours. \ 380 TITCHENER AND PYLE—ON THE AFTER-IMAGES jjuly23, 85.5° Red seen once, no color seen once. 87° Red seen twice, no color seen twice. The conditions can hardly have remained constant from 74.5° to 87°. Again, R on Hering gray no. 7 is seen colorless at 37°, while it is seen red at 39°, 41.5° (twice), and even at 47° (twice).* And yet again, G on. the same gray is seen colorless at 82°, green at 84°, and once colorless and once green at 87°." Instances of this irregularity might easily be multiplied. 2. If we turn to the special table for the limits of B and Y; we find a greater uniformity of result, but a certain arbitrariness in the selection of the limiting values. Thus, on various backgrounds and for different ob- servers, the limits for Y are taken as (a) 97°, although at 98.5° the color is seen 3 times out of 14, (b) 88.5°, although at 92.5° the color is seen once in 3 times, (c) 95.5°, although at 98.5° the color is seen once in 3 times, (d) 92.5°, although at 95.5° the color is seen 3 times out of 10, and so on. Similarly, the limits for B are taken as (a) 885°, although at 91.5° the color is seen once in 4 times, (b) 97°, although at 99.5° the color is seen once, and one observation is doubtful, if (c) 97°, although at 99.5° the color is seen 3 times out of 9, with one observation doubtful, and so on.* Now in her second paper, of 1908, Miss Fernald states that the paradoxical after-images “are perceived most frequently either just inside or just beyond the regular limits for the color.”** If this statement may be applied to the limits of color vision at large, 4. @., to the work of 1905, we must conclude that the crucial experiment has not been adequately performed; for the limits given are, as we have seen, irregular and arbitrary. Each, however, if we maintain that T’s results are conclusive for the Bk—W zone, we have still to account for the colored after-images of subliminally colored stimuli in the B-Y and R-G zones.** Miss * Tbid., 422. * Tbid., 416. *® Tbhid., 402. * Psychol. Review, XV., 33. * Miss Fernald uses the term “ unperceived,” not subliminal. The latter word is, however, employed by the Misses Thompson and Gordon, whose results Miss Fernald assimilates to her own. That “unperceived”’ really means “ imperceptible” is shown also by a passage in a letter received from Miss Fernald: “I should be very much afraid of my observer’s life, if it depended on his identification of the stimulus color, in all cases in which a clearly colored after-image is seen. In fact, when forced to say what stimulus he thought was used, he guessed at B for O as often as O for O, insisting all the while that he did not see any color.” 1908. ] OF SUBLIMINALLY COLORED STIMULI. 881 Fernald has been good enough to send us an account of the condi- tions under which her observers found the after-image, and to make a special series of observations, with Mr. C. E. Ferree as observer. “The head,” she says, “ must be held firm (my method is the bit, with the impression of the teeth). The background must be light, and the illumination good. The observer must hold the fixation steadily after the stimulus is removed. The after-image screen must be white to obtain Y or B after-images and black to obtain R after-images. A very slight change in conditions makes a great difference in results, which seem to me to depend wholly on bright- ness.” Professor Baird was acquainted with these conditions be- § fore he undertook his perimetrical observations. The new set of observations is as follows. Observer: C. E. Ferree. Full illumination on bright day {May 17, 1908). Nasal meridian, right. White ground. Projection field white, except in obs. 14-17, when it was black. Stimulus, 13 sq. mm. Distance from eye to stimulus, 25 cm. Fixation Point. Stimulus. Color Seen. aAfter-image, 80° O Dark gray Unsaturated light blue 85° B Just dark Wash of unsaturated yellow 85° tj Nothing Nothing 80° + Tinge of dirty yellow Very pale blue 80° Medium gray Dark White 80° O Indefinite gray Nothing 80° Light gray Dark White 75° Y Reddish yellow Good blue 95" B Good blue Good yellow 75° B Good blue Good yellow 65° OO», Yellowish red Unsaturated blue 65° y Reddish yellow Blue 60° G Indefinite greenish gray | Uncertain 65° G Greenish yellow Dark red, more satu- rated than stimulus 80° Medium gray Dark Nothing 80° Medium gray Dark Nothing 65° G Nocolor | Flash of red 65° R No color Blue Positive results occur in the two first and two last observations of the series. The former may be explained in terms of chromatic adaptation. If, as the illumination suggests, the observer began the PROC, AMER. PHIL. SOC., XLVII. 189 Y, PRINTED OCTOBER 3, 1908. 382 TITCHENER AND PYLE—ON THE AFTER-IMAGES [July 23, work in Y-adaptation,”® the first, blue after-image would naturally follow. If the second observation was taken at too short an interval of time, the resulting B-adaptation would show itself as a yellow after-image. The two final observations suggest a shift of condi- tions. G is seen at 65° as greenish yellow, and as colorless; at 60° as indefinite greenish gray. It is possible that, in the case in which ° “no color” is reported, the G, simply escaped notice; peripheral colors at the limit of vision often appear as momentary flashes. Again, R is reported at 65° as “no color,” although “ reddish yel- low’ had been seen as far out as 75°. It is possible that the flash of red escaped notice; it is also possible that R-adaptation, from the preceding after-image, brought out the blue. The puzzling thing is that the positive outcome should be thus definite in the Mount Holyoke and Bryn Mawr laboratories, while neither Professor Baird nor ourselves—though working with full knowledge of conditions, and though trying various possibilities which have not been reported in detail?°—are able in a single case to obtain the colored after-image. We can only guess at an expla- nation ; and we offer the following guesses in what seems to us to be the order of their likelihood: (1) chromatic adaptation ;21 (2) the momentary and flash-like appearance of colors at the limit of vision ; (3) the phenomenon of “ fluctuation of attention”; (4) de- fective method and unsystematic procedure in the determination * These observations were taken “after the limits had been roughly de- termined in previous experiments.” If the determination of limits was made at the same sitting, and if the last test-color employed was O, there would be additional reason for an initial Y-adaptation. ” Thus, Mr. Ferree wrote to us: “After-images seem to occur most in- tensively when the stimulus is removed while adaptation is still going on. If one carries the stimulation to a stationary point in adaptation, the after- image will weaken in proportion to the length of time during which the stimulus is regarded before the after-image is evoked. This is true whether one uses intensive or slightly supraliminal stimuli.” We thought that it might possibly be true of subliminal stimuli, and accordingly made brief observations both in light and in dark adaptation. But we never saw the after-image. **On chromatic adaptation, see Baird, op. cit., 57 ff., 64 ff., 73 £.; Journ. Philos., Psychol. & Sci. Meth., I1., 1905, 21. ' % 1908 ] aK SUBLIMINALLY COLORED STIMULI. 383 of zonal limits ; ( 5) unnoticed variations, physical, physiological or psychological, in the conditions of observation during a series.”* We are well aware that negative experiments are logically in- conclusive.** The fact that we have failed to find the colored after- image does not prove that this after-image is non-existent. We have, however, attempted a positive explanation: for Tschermak’s result, in terms of prepossession and inaccurate method; for Miss Fernald’s result, in terms (predominantly) of chromatic adaptation. Further experimentation by other observers must show whether our hypotheses are correct. We are aware, also, that the charge of prepossession is double- edged, and that we may ourselves be accused of an initial bias. We freely confess that we, as well as Professor Baird, approached the peripheral experiments in a sceptical attitude of mind. On the other side, we may point out that the scepticism was positively based upon the results of Baird’s Carnegie Institution research, and that the student-observers at the University of Illinois knew nothing of the question at issue. In the case of Tschermak’s observation, however, our initial bias ‘was positive ; we were surprised at the uniformly negative character of our results with the Marbe mixer. Tschermak’s position seemed to accord well with “current visual theory. Moreover, we knew that a contrast-color may be more saturated, may appear more “real,” than the inducing, objective color. We knew that Hey- mans, in his experiments on “ psychische Hemmung,” had some- times seen the contrast-color while the inducing color was still un- perceived.2* We knew of Helmholtz’ statement, “dass die gesat- Tn a letter to T Miss Fernald remarks: “ You will see that colored after- images were seen in less than one third of the total number of cases in which the stimulus-color was not seen.” In a communication made to Professor Baird, she estimates, roughly, that the phenomenon appeared in about five per cent. of her exposures upon the peripheral retina. This sporadic and fortuitous character of the after-images suggests that they are the product of some variable condition which has not been taken account of in the investigations. 7. S. Mill, “A System af Logic,” 1884, 515; W. S. Jevons, “ The Prin- ciples of Science,” 1900, 434. *G. Heymans, Untersuchungen iiber psychische Hemmung, i. Zeits. f. Psychol. u. Physiol. d. Sinnesorgane, XXI1., 1899, 328. “Wo mit weissep Sectorenscheiben experimentirt wurde, kam es 6fters vor, dass ehe noch der Ring die Farbe des Papierstiickes erkennen liess, sich im Hintergrunde schon die Contrastfarbe bemerklich machte.” ‘ Mead “ fo“ etiens « Je” +, PY . 384. TITCHENER AND PYLEON THE, AFTERSIMAGES [July 23, * “ ae festa. ‘objectiyen . Farben, welche axistingn, die‘ #einen Spectral- farben* im unesmiideten Auge nochgnicht, die gésittigste Farben- empfindung hervorrufen, welche iiberhnditpiemsglich ist, sondern dass wir diese erst erreichen, wenn wir das Auge gegen die Complemen- tarfarbe unempfindlich machen.” *® There was, then, no a priori reason to doubt Tschermak’s result; on the contrary, we thought it probable that under conditions which were unfavorable to the ap- pearance of the stimulus-color, but favorable to the appearance of its complementary, the subliminally colored stimulus would give a perceptibly colored after-image.*® As a matter of fact, it did not. * “ Physiol. Optik,” 1867, 370; 1896, 520. Cf. W. Wundt, “ Physiol. Psychol.,” II., 1902, 146. >This possibility was considered, also, in the peripheral work; so that even for that our bias was not wholly negative. ‘ ON THE CLASSIFICATION OF THE CETACEA. By FREDERICK W. TRUE. (Read April 24, 1908.) In this communication I wish to call attention to the various changes in the generally-accepted classification of the Cetacea pro- posed by Professor Dr. O. Abel, of the University of Vienna, in connection with his recent study of the Miocene toothed whales— chiefly those obtained from the vicinity of Antwerp, and now in the museum of Brussels.t_ Professor Abel’s classification (1905) is as follows: Odontocétes + Archéocétes -+ Squalodontidze Physeteridz Ziphiidee a Eurinodelphidee Argyrocetinz Acrodelphide . . .} Acrodelphinze + Saurodelphide ~ | Iniine Platanistidz Beluginz Delphinidze I would call attention particularly to the following features to which my remarks will mainly relate: 1. The use of the term “ Odontocétes” for all toothed whales and zeuglodonts. 2. The subordination of the “ Archéocétes” to the “ Odonto- cétes.” 3. The new family Eurinodelphide. 4. The new family Acrodelphidz (should be Iniidz). 5. The inclusion of Delphinapterus and Monodon in this family instead of in Delphinide, and the inclusion of Stenodelphis and Pontistes. *Mém. Mus. Roy. Hist. Nat. Belgique, 1, 1901 and 3, 1905. 385 386 © TRUE—ON THE CLASSIFICATION OF THE CETACEA. [April 24 6. The new family Saurodelphide. 7. The family Platanistide, consisting of Platanista ony; The zeugloddnts are included in the order Cetacea by the ma- jority of cetologists, though they were rejected from the great “ Osteography ” of Van Beneden and Gervais, as these authors did not consider them to be cetaceans. Brandt placed them with the -squalodonts as families in a tribe subordinate to the Odontoceti,? but nearly all other authorities have considered them as a distinct sub- — order,—Archezoceti, or Zeuglodontes. It seems to be generally agreed that the zeuglodonts have been proven by the researches of Dawes, Fraas, Stromer, Andrews and others to be derived from the creodonts. I do not know from what particular creodont they are supposed to have sprung, and whether the connection is good in that direction is for those most familiar with the creodonts to decide. The chief argument appears to be that in some zeuglodonts some of the molars are three-rooted. Whatever may be the truth as regards that connection, various zoologists have proposed, in more or less definite terms, to unite the zeuglodonts to the ordinary cetaceans through the squalodonts, which are clearly cetaceans, but with two-rooted or three-rooted teeth having serrated crowns. Professor Abel advances the con- crete proposition of uniting the zeuglodonts and_squalodonts® through the small form from the Caucasus, described by Lydekker under the name of Zeuglodon caucasicus,* and afterward made the basis of a new genus, Microgeuglodon, by Von Stromer. Of this only a part of the lower jaw, the humerus and a caudal vertebra, are known. The upward turn of the superior margin of the jaw pos- _ teriorly, and the form of the humerus—particularly the quite good articular facets—appear to me to indicate that this is a zeuglodont, with no very strong leaning toward Squalodon. If this be con- ceded, there is no way at present in which to connect the Cetacea with any group of land mammals. I would point out in this connection that while Microzeuglodon is from the Eocene and is of small size, and Squalodon is from the *Mém. Acad. Imp. Sci. St. Petersburg, VII® Série, XX, 1873, p. vii. * Ty). Cao. ee * Proc. Zool. Soc. London, 1892, p. 558, pl. 36. 1908] TRUE—ON THE CLASSIFICATION OF THE CETACEA. 387 Miocene and Pliocene and is of comparatively large size, there is an American form of squalodont which is either from the Oligocene or Lower Miocene, and is of small size. This is the genus Agorophius. It is based on a skull from South Carolina. It has serrate teeth like Squalodon, but what is especially remarkable, the parietals occupy a long area on the top of the skull. while in Squalodon and existing cetaceans the frontals and occipital come together at the vertex so as to entirely, or almost entirely, — exclude the parietals.» The very remarkable conformation of Agorophius led Van Beneden and Gervais, and also Cope, to suspect that it might possibly be the progenitor of the whalebone whales. I do not think this is likely, but Agorophius appears to indicate that S qualodon may have, and probably did, originate from forms very unlike Z euglodon, It might be supposed that the whole argument concerning the derivation of the Cetacea from the zeuglodonts was negatived by the occurrence of various characteristic forms of Cetacea in the Eocene and even earlier formations, and hence contemporaneously with, or earlier than, Zeuglodon. In all such cases, however, so far as I have traced them, the forms reported are really from the Mio- cene. A notable case is that of the various important forms from Chubut, Patagonia, described by Lydekker in 1893. These include such genera as Scaldicetus and Paracetus, which certainly occur in the Miocene of North America and Europe, and, indeed, I under- stand the deposits at Chubut to be assigned at present without dis- pute to the Miocene. The matter of the history and development of Squalodon is especially important, as Professor Abel derives four families of cetaceans from the squalodonts, namely, Physeteride, Ziphiide, Eurinodelphide and Acrodelphide (or Iniidz), and one of them— the Physeteride—directly from Squalodon itself. The main argu- ment in the latter case is that the teeth of some species of Scaldi- cetus (or Physodon)—an intermediate genus—have a ridge on the crown. This seems an unimportant character relatively, and does not balance the difficulty of deriving the extremely concave skull of Physeter from the extremely flat skull of Squalodon. *Sée’ True, “Remarks on the Type of the Fossil Cetacean Agorophius pygmeus (Miiller),” Smithsonian Publ., No. 1694, 1907, with 1 plate. 388 TRUE—ON THE CLASSIFICATION OF THE CETACEA. [April 24 I think that we shall in the end come to agree with the opinion expressed many years ago by Dr. Theo. Gill,® that the origin of the Cetacea dates much further back than is generally believed, and that the forms above mentioned are sideshoots from a stem reaching into a much more remote past. ’ However it may be as to the origin of the families mentioned, Professor Abel is correct, I believe, in following the course of Gray’ ~and Gill® in separating the sperm whales and the beaked whales into two families, the Physeteride and the Ziphiidz. Abel’s line of de- velopment for Physeter through Scaldicetus, Physeterula, Prophy- seter and Placoziphius seems excellent, except that it ignores Hypo- cetus Lydek. (or Diaphorocetus Amegh.) of North and South America, which is certainly an ancestor of Physeter or Kogia, and probably the former. The family Eurinodelphide of Abel is quite certainly distinct. While obviously allied to the Ziphiide, Eurinodelphis has distine- tive characters of its own, such as the small pterygoids, very long toothless premaxillze, a delphinoid prenarial region, etc. I suc- ceeded in discovering a skull of this genus in the Miocene of Mary- land last year and thus introducing the family into the American fauna. Abel’s family Acrodelphidz, which, as Professor Eastman re- cently pointed out, should be called Iniidz®, while not entirely new, is a very interesting assemblage. It comprises the following sub- families and genera: Family In1mp Gill (AcRopELPHID# Abel). _ Argyrocetus. Cyrtodelphis. Argyrocetinze 0s 20a eee 4 Pontivaga. | Ischyorhynchus. | Champsodelphis. Acrodelphis. Atrodélphing 020.0. 4 { Heteredelphis. * Amer. Nat., 7, 1873, p. 2. "Cat. Seals and Whales Brit. Mus., 2d ed., 1866, p. 326. * Smithsonian Misc. Coll., 11, 1872, p. 15. * Bull. Mus. Comp. Zool., 51, 1907, p. 86. 1908] TRUE—ON THE CLASSIFICATION OF THE CETACEA. 389 Inia. SIVAN sc Cea a: socal wmrae ..- + Pontistes. Stenodelphis, : Beluga. Feel. sis, 0: ci etsy «usb | Soh gon The partial breaking up of the currently-accepted families Plat- anistidz and Delphinidz here shown is quite radical. Usually Plata- nista, Inia and Stenodelphis (the so-called “ river-dolphins”) are united to form the family Platanistide, but Professor Abel leaves only the genus Platanista in that family. The limits of the family have always been uncertain, and Sir Wm. Flower, though accept- ing it provisionally in.its usual form, remarked: ‘“ There are three distinct genera, which might almost be made the types of families, but it is probably more convenient to keep them together, only regard- ing them as representing three subfamilies.”!° Stenodelphis, although having separate cervicals and broad lum- bar diapophyses like Inia, has involuted pterygoids, ossified sternal ribs, and the articulations of the ordinary ribs with the vertebre as in Delphinide. Associated with it is the fossil genus Pontistes of South America, which resembles Stenodelphis very closely, but is larger. The prenarial region in these genera, as well as the form and position of the nasals and the form of the zygomatic processes, recall Phocena and also Inia, but I have been unable to satisfy my- self of the importance of these resemblances. The most radical feature of Professor Abel’s classification is the removal of the white whale and narwhal (Delphinapterus and Monodon) from the Delphinidz to the Iniidz, although it is true that these forms had previously been considered as constituting a separate subfamily of the Delphinidz by Gill, Flower and myself. They agree with Jnia in having no dorsal fin, a broad pectoral, and separate cervical vertebre, and the diapophyses of the lumbars are somewhat expanded. On the other hand, the sternal ribs are ossi- fied, the sternum is shaped as in other Delphinide, the ribs articu- late with the vertebre in the same manner as in that family, and the enamel of the teeth is smooth. This combination of charac- * Flower and Lydekker, “ Mammals Living and Extinct,” 1891, p. 258. 390 TRUE—ON THE CLASSIFICATION OF THE CETACEA. [April 24 ters recalls Stenodelphis rather than Inia, although the former has a dorsal fin. Professor Abel’s chief reason for Ssocting Delphinapterus and Monodon from the Delphinide appears to be that the cervical ver- tebree are separate. He says that on this account they cannot be derived from Delphinide.** This seems to me illogical, for it must be true that the existing Delphinide with extremely thin, more or less rudimentary, and anchylosed cervicals were derived from forms with well-developed, separate cervicals. Hence, one might expect to find some forms still existing in which the cervicals are distinct. I do not think that on that account alone they should be rejected from among the Delphinide. In this connection, the genus Sctahociads from the Miocene of Maryland is of interest. This is represented by a skull and cervical vertebra. The skull, which is long-beaked, is delphinoid in general appearance, especially in the prenarial region, but the temporal fossze are large and the supraoccipital narrow, and shaped somewhat as in Inia. The teeth are lacking, but appear to have had simple cylindrical roots. The cervical vertebree are separate. They are, however, imbedded in the ‘matrix, so that little can be determined regarding their characters. This genus has been associated with Inia in the Platanistidz by Cope;? and Dr. C. R. Eastman, who has recently given a new description of it,1* also regards it as allied to Jnia, while Brandt and Abel have considered it closely allied to Delphinapterus. I am myself inclined to the latter view, although conceding that the shape of the supraoccipital is inioid. If this be accepted, we have in Lophocetus a Miocene delphinoid form with separate cervicals. On account of the combination of characters presented by Steno- delphis, Delphinapterus, Monodon and Lophocetus, three courses are possible as regards their classification. They may be included in the family Iniidz, or made the basis of a separate family Steno- delphidz, or included in the family Delphinide. The latter course seems to me best at present, 4 Mém. Mus. Roy. Hist. Nat. Belgique, 3, 1905. * Amer. Nat., 1890, pp. 606 and 615. * Bull. Mus. Comp. Zool., 51, 1907, p. 79. 1908] | TRUE—ON THE CLASSIFICATION OF THE CETACEA. 391 Professor Abel has described a delphinoid form from the Upper Miocene of Antwerp—Pithanodelphis—in which the atlas and axis are united as in existing genera. It would appear, from this and other evidence, that the family Delphinidz was differentiated as early as the Miocene and that both forms with separate cervicals and forms with united cervicals were then existing. The -family Saurodelphide of Abel comprises the single genus Saurodelphis Burmeister, from the banks of the Parana River, Argentina. The geological horizon is understood to be Pliocene. Professor Abel considers that it cannot be associated at present with any group of toothed whales, but it appears probable from Burmeister’s figures that the skull has a maxillary hood and other characters resembling those of Platanista, and the teeth are also similar in some respects, especially as regards the growth of irreg- ular roots with age, etc. For these reasons, I think it should be assigned to the Platanistidz, at least provisionally. The modifications which I have proposed in the classification of the toothed whales are summed up as follows: CETACEA. ODONTOCETI. + Squalodontide. 2 Physeterine. BPR OUOEB SE 6 hg Pe geass 2.0/0 6 4s 9 | Kogiinee. Ziphiide. + Eurinodelphide. Iniinz. SOMIGIE SS 5.328 Si PERE x in Ke gloss Argyrocetine. 1 Acrodelphinz. Stenodelphinz. MOLINE yo whic .s8 5 expanse HDS Delphinapterinz. Delphinine. Eurinodelphide. . \ . . thy i nen : ate inte Py heed : id if / ‘ Te es PROCEEDINGS OF THE AMERICAN PHILOSOPHICAL SOCIETY HELD AT PHILADELPHIA FOR PROMOTING USEFUL KNOWLEDGE Vout. XLVII Sept.—Dec., 1908. No. 190. HEREDITY, VARIATION AND EVOLUTION IN PROTOZOA. II. HEREDITY AND VARIATION OF SIZE AND Form 1N PARAMECIUM, WITH STUDIES OF GROWTH, ENVIRONMENTAL ACTION AND SELECTION.? By H. S. JENNINGS. 3 (Read April 24, 1908.) TABLE OF CONTENTS. (See pages 544-546.) I. INTRODUCTORY. The first of this series of studies? gave a general introduction to the investigations, and dealt with the fate of new or acquired char- acters in protozoa, showing that these are as a rule not inherited and that there is no difference in principle on this point between protozoa and metazoa. The present paper takes up heredity and variation in size and form in Paramecium. Our present questions are then mainly as follows: In what respects do the individuals of Paramecium resemble each other? In what From the Laboratory of Experimental Zodlogy, Johns Hopkins Uni- versity, Baltimore, Md. * Journal of Experimental Zoélogy, Vol. 5, 1908, pp. 577-632. PROC. AMER, PHIL. SOC. XLVII. 190 Z, PRINTED JANUARY 8, I909. 394 JENNINGS—HEREDITY IN PROTOZOA. [April 24, respects do they differ? What are the causes of the resemblances or differences, as the case may be? i The attempt is made to treat these questions broadly, determin- ing experimentally the different classes of causes concerned, without prejudice as to their relative importance. External and internal fac- tors are therefore equally considered, the purpose of the investiga- tion being to give as complete an analysis of the phenomena of resemblances and differences as possible. Our problem, then, requires an analysis from this point of view of all things which may result in producing, increasing or decreasing the similarities and differences between individuals—reproduction, growth, conjugation, the effects of environment, of selection, and the like. The investigation will be best introduced by proposing at once what is really the central problem—that concerning heredity. Is size inherited in Paramecium? How would heredity of size be shown? If certain individuals differ in size, and the progeny of these individuals, under identical conditions, show corresponding differences, this is what would com- monly be called heredity of size. “ Heredity is a certain degree of correlation between the abmodality of parent and offspring ” (Daven- port, 1899, p. 35). Do large individuals of Paramecium produce, under the same conditions, larger progeny than do small ones? Is it possible to obtain by selection large and small races of Paramecia? To study this question, we must first examine the variations in size commonly found in Paramecium. II. PRELIMINARY STUDY OF VARIATION IN PARAMECIUM. We owe our present knowledge of variation in Paramecium mainly to Pearl and his co-workers (see Pearl, 1907; Pearl and Dunbar, 1905). A more extensive work by Pearl on variation in Paramecium has been mentioned as in prospect; I learn from per- sonal communication, however, that this is not to appear. I shall therefore publish my own results more fully than I should otherwise have done. Certain points in connection with variation in Para- mecium have been dealt with by Simpson (1902) and Pearson 1908.] JENNINGS—HEREDITY IN PROTOZOA. 395 (1902) ; also by McClendon (1908). But we have at present nothing like a thorough analysis of the matter, based on extensive data. I. GENERAL MeEtTHops oF Work; STATISTICAL TREATMENT AND Its UsEs. Before we can study experimentally the nature and causes of the existing variations, we must, of course, know their extent, character and distribution. To this end I have made a statistical study, con- structed frequency polygons, and determined the more important constants of variation and correlation. This has, of course, not been done because of belief in any occult virtue in mathematical treat- ment. Statistical methods have been used in this preliminary survey merely because they form the most natural and direct way of discov- ering and displaying the problems on which we wish to work ; I doubt whether the most determined critic of the use of such treatment in biology could suggest any other way for our material. But I am fully convinced that “crucial evidence is always individual in the last analysis” (Whitman) ; that the preliminary statistical examina- tion of the facts requires development as soon as possible into precise experimental knowledge. It is valuable to know just how many men out of a thousand will die in a given period, but it is infinitely more valuable to know which ones will die if the conditions are not changed, and why; and the latter knowledge includes the former. I have therefore advanced at once from the descriptive statistical work to experimental treatment. A curve or polygon of variation (such as Diagram 1) or a correlation table (such as Table I.) is to be looked upon as a mass of problems. The place occupied in the polygon or table by any individual is due to certain causes, and it is these causes that we seek. In seeking these causes by experimental methods, statistical treatment is again found to be of the greatest value for detecting and registering the effects of single factors, under complex condi- tions. This method may be compared to a microscope; it enables us to detect and deal with causes and effects which we could not handle without it. JI am convinced that it is a great mistake to hold that the only or the main use of statistical treatment is for “ dealing 396 JENNINGS—HEREDITY IN PROTOZOA. [April 24, with the sphere of indefinitely numerous small causes—amenable only to the calculus of chance, and not to any analysis of the indi- vidual instance.” Such treatment is a most valuable instrument for precisely such analysis as will bring out the effects of individual factors when we are unable to experimentally disengage them com- pletely from others; it aids us most essentially in the “analysis of the individual instance.” Of this I hope the present paper may fur- nish illustrations. As Johannsen (1906, p. 98) has well expressed it, the mathematical treatment must, to give valuable results, be “ based upon an accomplished sorting of the special facts and a biological setting out of the premises which are to be treated.” Davenport (1899) states that “the statistical laws of heredity deal not with the relations between one descendant and its parent or parents, but only with the mean progeny of mean parents.” The object of the present work is precisely to discover so far as possible the relation between one descendant and its parent (or other rela- tives) ; for this, statistical methods show themselves most useful. 2. A TypicaAL CULTURE. Wewill then first examine a typical culture of Paramecium, made in the usual way with pond water and decaying vegetation, in a circular glass vessel about nine inches across and three inches deep. This culture we will call Culture 1. Inspection showed that Paramecia of markedly different size were found in this culture, so that it seemed a favorable one for a study of inheritance in size. Cursory examination seemed to indi- cate the existence of two sets of individuals, those of one set being nearly double the length of the others. Of this culture a large number were killed on April 10, 1907, and four hundred specimens, taken at random, were measured as to length and breadth. 3. Metuops oF MEASURING AND RECORDING. The animals were killed with Worcester’s fluid, which is known to cause practically no distortion when properly used. Worcester’s fluid consists of ten per cent. formalin saturated with corrosive sublimate. In using it, a large number of the infusoria must be brought into one or two drops of ok) JENNINGS--HEREDITY IN PROTOZOA. ' “397 water, then these must be overwhelmed with a considerable quantity of the fluid. If the infusoria are in a larger quantity of water, the killing takes place more slowly, the animals have time to contract, and distortion results. The measurements were made on the slide, the organisms being either still in the killing fluid or in ten per cent. formalin. Transference to the latter has no effect on the form of the fixed animals. Most of the meas- urements were made directly with an ocular micrometer. In the case of cultures of large individuals, however, the form was projected on paper with the camera, in the way described by Pearl (1907), the extremities of length and breadth marked with the pencil, then these were measured with a scale made by projection of the ocular micrometer. Such combinations of lenses were used that one division of the microm- eter scale was equal to 4 microns (or in a few cases, which will be expressly noted, to 34 microns). The measurements were thus recorded in units, each of which was equal to 4 microns, so that the recorded units are multiplied by four to give results in microns. When the measurements fell between two lines of the micrometer, the line nearest the actual measure was that re- corded; if the measurement fell just half way between two lines, the higher line was recorded. Thus, the recorded unit 45 included all measurements beginning with 443, and less than 454. In the tables, the measurements, given in microns, are therefore grouped about such values that each group includes values from two microns below to two microns above the one recorded. Thus, in Table 1, the length 180 includes all the specimens meas- uring from 178 up to (but not including) 182. It will be well to summarize here, once for all, the method of treating the data obtained in the measurements. For most of the tables the con- stants computed (and recorded below the tables) were the following: the mean, standard deviation, and coefficient of variation, for length and for breadth; the mean index or ratio:of breadth to length; and the coefficient of correlation. The computation of the constants was based on the well- known formule that have been brought together by Davenport (1904) and others. I used as a rule the actual methods set forth so clearly by Yule (1897). The computations were made by the aid of seven-place logarithms and of Crelle’s and Barlow’s tables. Two independent computations, at considerable intervals of time, were made in each case. While I cannot hope that errors in computation are excluded, I believe that such as may exist do not in any way affect the conclusions to be drawn. Certain points of detail should be mentioned. While, as will appear, most of the tables do not give symmetrical curves, I have used only the simple statistical methods applicable in strictness to such curves; the methods are quite sufficient as a basis for the comparisons we wish to make. In computing the standard deviation, Sheppard’s correction of the second moment was used throughout. That is, if we employ the method of Yule (1897), o= VX( f§*) — d? — .08333, or using the signs employed by Davenport (1904) x( V— V%)? RY fast TA | C= . r, Ts: [April 24, ‘ngiz6b ‘dnoiry purpy Wsry jo :ng6eee ‘dnoiyy puezy io] JO YIpeorg uv] ‘nzL600z ‘dnois) puezy WS jo :wozh'Sz1 ‘dnoiy puezy }yey JO YiSsuayT uvoyy ‘nogg'gh ‘Yproig uray ‘norg’Sol ‘YySusT] URsyy ‘SUOIOIP, UL YpRoig JENNINGS—HEREDITY IN PROTOZOA. 398 oop |1 1 9 § GirSibetezigiozZior Zorg vy S £1010 ggigréeSztelzgiz1€ 420071 I ‘s[eoy z I I v9 L I 09 of I z , JG34 Spe et I 9S oS zZ £ PSG, beter I zs S9 I I ¥ S$ S28 Watt Lz I gv 6S I £25 -O54-8°3-32 2% I Zz z I vv QI I z I Fa S € I I ov SV I £ OS 92650 9f L6 yg 641716169 FE 1 ze Lz | one ieee ao | vi 82 OLIRSSSSERRISISSRSSIVAASAAEEEGASESESSSS ee gee SSR ERPESESE SRS Se eae ee Soe eR CAS OLS ASSES ESBS EE ‘SUOIDITA Ul YSuaT (‘0 pue Pp suosdjod ‘z pue I suieiseiq 29S) ajquvs mopuny v fo yjpvaig pun yJsuaT sof ajqvy, woynjad4oy) “I a4nqny .. PIM ,, ‘I qlavye 1908.] JENNINGS—HEREDITY IN PROTOZOA. 399 The mean index given below the tables is the mean of the quotient breadth i length This mean was found, without computing the index for each individual, by the following formula: : it shows essentially what percentage the breadth is of the length. Nee, i=Z + Cr? —rCpCr): Where 7 is the mean index, Az is the mean breadth, Az the mean length, Cpr the coefficient of variation for breadth, Cz the same for length, and r is the coefficient of correlation between length and breadth. I am greatly indebted to Dr. Raymond Pearl for assistance in the mathe- matical treatment of the data. The results of the measurements of a random sample of 400 of Culture 1 are given in Table I. It is evident on inspection of this table that the individuals fall into two well-marked groups, one set varying in length from 84 to 144 microns, the other set varying from 164 to 240 microns, while between these groups, in the region from 144 to 164 microns, only two specimens are found. The mean length for the entire sample falls at 165.840 microns, almost precisely in the region where no specimens are found. The smaller set have their mean length at 125.420 microns: the larger set at 200.972 microns. These results are shown as frequency polygons in the lower por- tions of Diagrams 1 and 2. 4. METHOD oF CONSTRUCTING THE POLYGONS. In making the polygons for length, three units of measurement (12 microns) were grouped together to make a single unit of the abscissa of the polygon. This was done in order to destroy any irregularities due to un- conscious prejudice on the part of the measurer for certain numbers. Thus, in measuring a large number of individuals, it-may be found, for example, that few are recorded at 51, while at 50 there are many; or the reverse may occur. This is due only to the fact that in doubtful cases falling between these numbers the measurer unconsciously gives the preference regularly to one of them. The error thus introduced is extremely small (it can hardly be more than one micron in any case), but if the polygon is made without grouping together adjacent classes, there appear extreme irregularities in its outline, irregularities that are quite without significance. When three units are thrown together, any marked irregularities remaining in the poly- gons are almost certainly due to peculiarities in the material itself. It is of course possible that small peculiarities really existing may be hidden in 60 I 55 ! t 13 iy fe) as e 5 Oe : ne 4 T T ! | D 40 Frequency in Percentages ) a ~ i F_ | ez 20 es i fi \\ (lee l Lie st 8 A ] a ae ; ae VA 80 92 104 116 128 140 152 164 176 188 200 212 224 236 Length in Microns. DracraAM I. Polygons of variation for length in Culture 1 and its de- scendants. A and a form together the polygon for 400 specimens taken at random from the original culture 1, on April 10, 1907. B, polygon for 100 descendants of ten of the larger individuals of Culture 1. D, polygon for 100 descendants of the single large individual D, from culture 1. b, polygon for 100 descendants of fifty smaller individuals from culture 1. c, polygon for 100 descendants of the single small individual ¢c, from culture 1. 4 1908.] JENNINGS—HEREDITY IN PROTOZOA. 401 2) ef an ah a p<] nd S & ~ Tt f ASL 10 / | ; rand a 'y i Re ia / L / 4 ‘\ 3 5 ! N 4 / A ; 7 os \ a e \ ‘teed Ss o ae v rs) u 3) Ay & a >, 25 2) Q \ | vo : [\ a 4 15 ; | aaa AN \ N 20 24 28 32 36 40 44 48 52 56 60 64 68 72 76 80 Breadth in Microns. DracraAM 2. Polygons of variation for breadth in culture 1, and in its descendants from selected specimens. The letters have the same significance as in Diagram I. 402 ‘ JENNINGS—HEREDITY IN PROTOZOA. [Aprilz4, this way, but it was thought wiser to be conservative in this matter. Thus the space between two perpendicular lines of the polygons includes three of the groups of the correlation table, and is marked at its base with the middle value of the three groups which it includes. In making the polygons for breadth, it was found that there was little evidence of error due to unconscious preference for certain numbers in making this measurement. This is probably due to the comparatively small numbers of units in the breadth measurement, and to the fact that it is possible to hold both limits of the measurement on the scale sharply in the eye at once, while this is hardly possible in measuring length. In the poly- gons for breadth, therefore, one unit of the polygon was made to correspond to one unit of measurement (four microns). In all the polygons the numbers to the left indicate percentages of the entire number, so that all the polygons are of equal area, whatever the number of specimens on which they are based. The only exception to this is in the case of the double polygons a and A, of Diagram 1, resulting from plotting the random sample of Table I. Since this sample falls into two groups, the entire (double) polygon was made of twice the area of the other polygons. Each half polygon therefore becomes approximately equal to any one of the single polygons of the other diagrams, thus permitting ready comparison. _ The numbers at the foot of the diagrams are the dimensions in microns. Each number corresponds to the value of the center of the column beneath which it stands. 5. Two Groups OF PARAMECIA. Thus the Paramecia in our natural culture I fall into two groups which are almost completely separated, so far as length is concerned, but which overlap a certain amount in breadth. Characteristic out- lines of varied members of the two groups, drawn to the same scale, are shown in Fig. 1. ; Are these two groups permanent differentiations, such as might be called distinct species, or are the differences possibly due merely to temporary dimorphism of some sort? To answer this question individuals of the two sizes were isolated and allowed to multiply separately, in cultures made of boiled hay. After varying periods of time 100 individuals, taken at random, were measured from each of these pure cultures, and the frequency polygon derived from these was compared with the two (nearly distinct) polygons from the original culture. The following cultures were made and measured: 1. Fifty of the smaller individuals were selected from the orig- inal culture, placed together, and allowed to multiply for twelve days (from April 10 to April 22). The measurements of 100 of this 1908. | JENNINGS—HEREDITY IN PROTOZOA. 403 b a c d 290 So O Fic. 1. Outline of characteristic specimens ftom the original wild culture 1, April 10, 1907. The upper row shows examples of the larger “ caudatum form”; the lower row examples of the smaller “aurelia form.” d, Young of the caudatum form; h, dividing specimen of the aurelia form. All X 235., culture are shown in curve b (broken line), Diagrams 1 and 2; their dimensions are given in the correlation Table II. It is evident that this group corresponds in a general way with the smaller group of the original culture, though its mean length and breadth are some- what lower (96.280 X 29.080 microns instead of 125.42 X 33.396), and it shows a little less variation. 2. Ten of the larger individuals selected from the original cul- ture were likewise allowed to multiply in the same vessel for twelve days, then 100 were measured. The results are shown in curve B, Diagrams 1 and 2, and in the correlation Table III. It is evident 404 JENNINGS— HEREDITY IN PROTOZOA. [April 24, Taste II, Correlation Table for Length and Breadth of a Random Sample from De- cendants of 50 of the Smaller Individuals from Culture 1, allowed to Multiply for 12 Days. (See polygons b, Diagrams 1 and 2.) , Length in Microns. g 80 84 88 92 96 100 104 108 112 116 120 124 128 o 20 I 2 3 = 24 5 a! aoe I 16 28 MS. 30 Bins aes I | 40 ey B21 rae Bn en SN a Rs Maa 33 ~~ 36 r 3 3 I S matey a POTS “ONION A Vente or TO! Res 6. Oe in aes Length—Mean, 96.280 = .552¢ Breadth—Mean, 29.080 + .212" St. Dev., 8.160 + .388u St. Dev. ~~ 3.320 .168" Coef. Var., 7.678 + .368 Coef. Var. 12.100 .585 Mean Index, or Ratio of Breadth to Length, 27.428 per cent.; Coef. of Cor., .3768 + .0579. that the progeny of these ten correspond to the larger set (A) of the original culture, though with slight differences in the means and in the amount of variation. 3. A single smaller individual, c, was selected from the original culture. As near as could be measured when alive, this individual Tas_e III. Correlation Table for Length and Breadth of a Random Sample from De- scendants of 10 of the Larger Individuals from Culture 1, allowed to multiply for 12 Days. (See polygons B, Diagrams 1 and 2.) Length in Microns. 144 148 152 156 160 164 168 172 176 180 184 188 192 196 200 204 208 212 rs 48 I TeCxE I 4 Ba ie pie tk CENT: Ry ee Se eis Se I 16 = 56| I i melee Cape : aia 2 es age I 15 = 60 Pie tien hit 2:5 Be gee 23 B64 2 EE Re ey eae I II < 68 I Lz K MEAS Mines ae tay 15 a9 2 ease I 2 13 3,70 ee 2 Pt 80 I ith Iot2°5§°8 2 4°97 §) 9 iB ieee see Length—Mean, 182.760 + 1.096" Breadth—Mean, 61.360 + .496u St. Dev., 16.264 .776u St. Dev., 7.376 + .332¢ Coef. Var., 8809+ .428 Coef. Var., 11!912 + .576 Mean Index or Ratio of Breadth to Length, 33.652 per cent.; Coef. Cor., 5288 + .0486. 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 405 was 120 microns in length. It was allowed to propagate in a culture free from all other Paramecia, from April 9 to June 11 (thus a little * more than two months). Now a random sample gave the polygons shown at c, Diagrams I and 2; the measurements are given in Table IV. This group corresponds very closely to the smaller group a of Taste IV. Correlation Table for Length and Breadth of a Random Sample Descended from the single small Individual c, taken from Culture 1 and allowed to Multiply 63 Days. (See Polygons c, Diagrams 1 and 2.) Length in Microns. é 104 108 112 116 120 124 128 132 136 140 144 148 152 156 a2) 28 | I RS a i 5 ZA 32 SG Bo ce. 24 36) 1 5 TAN SR ete Dk eee eae, ae I | 39 ‘40 ool Whee Seve walk ues WR Cena, Be 23 3 44 I a iy ye Pee 9 3 ee 5 ean oR Wana Rs tam Ae 6 ale © oe Xa MM OMe: Maa GY Length—Mean, 130.120 + .628u Breadth—Mean, 36.280 + .260" St. Dev., 9.284 + .443¢ St. Dev., 3.880 = .184m Coef. Var., 7.134 + .342 Coef. Var., 10.700 + .516 Mean Index or Ratio of Breadth to Length, 27.913 per cent.; Coef. Cor., .5208 + .0492. the original culture, though with slight differences in breadth. 4. A single very large specimen, D, approximately 250 microns in length, was isolated from the original culture on April 12 and allowed to propagate freely till June 11 (two months): 100 speci- mens taken at random then gave the measurements shown in the polygon D, Diagrams I and 2, and Table V. Examination of the polygons and tables* shows that the two forms retain their essential characteristics when isolated and propa- gated. The results shown in the diagrams are typical of many others. I have kept distinct strains of each of these groups for periods (at the present time) of more than eighteen months, and measurements made at frequent intervals during that time show that they have always remained quite distinct. Thus it is clear that these colorless Paramecia fall into two dis-. tinct groups, which are at least relatively permanent. As is well known, two species of colorless Paramecia have long been distin- 406 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE V. Correlation Table for Length and Breadth of a Random Sample Descended from the Single Large Individual D, taken from Culture I, and * allowed to Multiply 60 Days. (See polygons D, Diagrams 1 and 2.) Length in Microns. RESSISSSSTSLLSSRIBRsSreg ae ee ee eo Pi. i. io Me | 28 | I I ae 32 | I I = 36 I ae 6 & 4o | 2 ee so 13 = 44 | I 422% I 13 = 48 | a ERY UR he Bor He out 23 S52 | rt a Ce ik Bae Bik 1 | 18 56 | I I 2 pe A Weak 2 I 12 “5 60 | Tos I 5. S$ 64 | I Vick) te 5 v ) og 88 | I I 72 | re) 76 / I I - poeoeoottri12 4216141800462 6 2 tone Length—Mean, 188.360 + .g80u Breadth—Mean, 49.000 + .548u St. Dev., 14.532 + .692u St. Dev., 8.144 + .388u Coef. Var., 7.715 + .370 Coef. Var., 16.618 + .814 Mean Index, 26.029 per cent.; Coef. Cor., .4188 = .0556. guished under the names Paramecium aurelia Miller and Para- mecium caudatum Ehr. The two groups we have found correspond to the descriptions heretofore given of the two species, the smaller set representing Paramecium aurelia, the larger Paramecium cau- datum. Besides the differences in size certain other characteristics have been held to distinguish the two species, and these distinguish- ing characteristics are evident in our two groups. Paramecium aurelia is described as having two micronuclei and P. caudatum but one; this is true for our larger and smaller groups respectively. Paramecium aurelia is said to be more rounded behind, while P. caudatum is pointed. In spite of many variations in form within each group, it is clear that our smaller group corresponds in this respect also with P. aurelia, the larger one with P. caudatum. Calkins (1906) has brought forward evidence tending to show that the supposed distinction into permanently differentiated forms is not well based, so that there are not two species, the different sizes being merely variants of one. Calkins based his doubts as to the 1908.] JENNINGS—HEREDITY IN PROTOZOA. 407 really specific distinctness of P. aurelia and P. caudatum on the fact that in one of his pedigree cultures of P. caudatum the number of micronuclei changed from one to two, remained at two for many generations, and finally changed back again to one. The results here published tend to indicate that the distinction into two groups is not without some sort of foundation. But it will be best to reserve the discussion of species until we have more data at hand. We may temporarily speak of the smaller set as the aurelia group, the larger one as the caudatum group. In a later part of the paper the question of distinguishing species will be taken up in detail, in the light of full data. 6. ARE DIFFERENCES IN SIZE HEREDITARY WITHIN EACH OF THE Two Groups? We have found that among the variations of Paramecium in size are two groups, limited by internal causes, so that even under the same external conditions they differ in size; these two groups have heretofore been considered two species. But within each of these groups we find likewise many variations in size, so distributed, how- ever, as to produce a curve with a single apex (Diagrams 1 and 2, etc.). These variations are at times very considerable, as will be evident from an examination of the polygons shown in Diagrams 3 and 6 (pages 413, 470), or the tables numbered VII. (page 412) and XX. (page 466). The next question to be considered is: Are the differences in size within such a group hereditary? That is, do the differences in size depend upon internal conditions, of such a char- acter that the differences will persist in the progeny, even when the external conditions remain the same? The experimental answer to this question is to be obtained by isolating individuals of different size belonging to one of the two groups (either “aurelia” or “ caudatum”’), allowing these to mul- tiply and determining whether the progeny show differences in size corresponding to those in the parents. Can we by selection and propagation produce within the limits of a single group races of different mean size? Experiments designed to answer this question were undertaken in the following way. As representing the caudatum group I 408 JENNINGS—HEREDITY IN PROTOZOA. [April 24, selected the cultures descended from the individual D; while the progeny of c represented the aurelia group. Now, from each of these groups the largest and smallest individuals were isolated and allowed to multiply, under uniform conditions. Thus, the selected large and small individuals of a given group were all progeny of a single individual, forming thus a “pure line”; this fact is of great importance, as the sequel will show. A large number of experiments gave throughout negative results. The progeny of large and of small individuals (within a given pure line) showed no characteristic differences in size. Large specimens of the caudatum form produced progeny on the whole no larger than those produced by small specimens of the same form, and the same was true in the aurelia group. In many experiments a single large and a single small specimen were isolated, and their progeny compared; in other cases a number of large specimens were placed together in one vessel, a number of small ones in another, and their progeny compared after lapse of a considerable period. Since the results of these experiments were throughout negative, I will give the details of but a single illustrative experiment: On July 27 ten large and ten small specimens were selected from a lot of the caudatum group, all being descendants of a single indi- vidual D. The ten large specimens measured, as nearly as could be determined while alive, approximately 250 microns each, and were thick in proportion to the length. The ten small specimens were about 150 microns long, and were thin. The two sets were placed in equal quantities of the same culture fluid. At the end of three days the large set had produced many indi- viduals. Fifty of these taken at random gave a mean length of 189.040 microns, a mean breadth of 60.560 microns. The smaller individuals did not increase rapidly and five of them died before dividing, so that all the progeny came from six indi- viduals. The six increased in size before dividing. At the end of three days there were twenty-one individuals. The mean length was 205.140 microns, the mean breadth 56.570 microns. Thus the smaller specimens had produced progeny that were a little longer, but not quite so broad, as those resulting from the larger set. The existing differences are clearly without significance. 1908 ] JENNINGS—HEREDITY IN PROTOZOA. 409 In other cases there was more variation in size among the dif- ferent sets of progeny of D, particularly if the measurements were made after but few fissions had occurred. But sometimes the progeny of the large specimens were smaller, sometimes larger, than those of the small specimens. On the whole, both large and small specimens produced progeny of about the mean size for the group, under the given conditions. Thus it is apparent that the differences in size shown within such a polygon as D, Diagram 1, are not due mainly to hereditary internal factors. Before we can determine with certainty whether any such factors are involved, we must make an analysis of the variation polygon, determining so far as possible the different fac- tors, external and internal, which go to make it up. 7. PROPOSED ANALYSIS OF THE POLYGONS OF VARIATION. Our present task is then to determine, so far as possible, what factors produce such polygons of variation as are shown in Dia- gram 1; to define what the individuals of different sizes and propor- tions really are, and to what their particular characteristics are due. There are several sets of problems to be considered; these we may classify as follows: 1. What are the causes and the significance of the variations shown in a single variation polygon, such as D, Diagram 1? Why, in a group of Paramecia grown under the same conditions, and perhaps all descended from the same ancestor, do certain indviduals show the mean length, while others are larger and others smaller? Each size must have its determining factors. 2. In different polygons from Paramecia of the same general group and even when-all are progeny of the same individual, the mean size differs much. Thus, in Diagram 6 (page 470) the mean length for polygon 8 is 146.108 microns; for polygon I1 it is 191.360 microns, though both represent descendants of the individual D, of the caudatum group. What are the causes of such variations in mean size among different sets of individuals? 3. In different sets of individuals belonging to the same general group, or descended from the same individual, the amount and range PROC, AMER, PHIL. SOC. XLVII. I90 AA, PRINTED JANUARY 8, 1909. 410 JENNINGS—HEREDITY IN PROTOZOA. [April 24, of variation differs much. This is readily evident to the eye on comparing the polygon 8 of Diagram 6 and its correlation table, XIX. (page 466), with polygon 9 (Diagram 6) and its table, XX. In the former the length ranges only from 120 to 176 microns, and the coefficient of variation is 7.003, while in the latter the range of length is from 120 to 220, and the coefficient of variation is 12.767. What is the cause of these great differences in the variation of different groups? 4. In different sets belonging to the same general group the correlation between length and breadth differs greatly. Thus, in Table XX. (page 466) the correlation is high and positive, a differ- ence in one dimension being accompanied, with much regularity, by a corresponding difference in the other. In Table XXXI. (appen- dix), on the other hand, there is almost no correlation, while in Tables XXIX. and XXXII. the correlation is marked, but negative —an increase in length being associated with a decrease in breadth, and vice versa. What are the causes and significance of these dif- ferences in correlation found in different sets? In dealing with these questions, there are three main sets of possible factors to be examined, as follows: 1. Hereditary Factors.—Some of the factors concerned may be internal and largely independent of the environment—so that the differences in size are hereditary. The existence and nature of such factors form our main problem, but they can be dealt with only after the other factors are investigated. 2. Growth—Some of the variations in size, and in ‘proportions, may be due to different stages of growth, so that this matter must be carefully examined. 3. Environmental Influences.—It appears probable that the dif- ferences in the means, the differences in the range and amount of variation, and in the correlation, may depend partly on the nature of the environment. We shall take up in detail these three sets of factors, beginning with growth. 1908. | JENNINGS—HEREDITY IN PROTOZOA. 411 III. GROWTH IN PARAMECIUM. One significant fact was noted in the breeding experiments described in a previous section. Whenever a large and small speci- men (belonging to a given group) were isolated at the same time, the large specimen as a rule divided first. Often at the end of forty-eight hours the large specimen had produced eight or sixteen progeny, while the small specimen had either not divided at all, or had produced but a single pair. This suggests that the differences in size may be largely matters of growth; that the small specimens may be young ones, and that the variations shown in the frequency polygons may be largely growth differences. It is clear that a study of growth in Para- mecium is imperative before intelligent work can be done with variation. The subject of growth in the Protozoa is an interesting one in itself, so that this study will be made as thorough as possible for its own sake, as well as for the light it throws on variation. Growth was studied by three different methods: (1) By obser- vation of abnormal specimens bearing localized appendages, noting the changes in position during growth; (2) by following the changes of form and size in living specimens; (3) by a statistical examina- tion of the dimensions of individuals of known age. The observations on growth in abnormal specimens have been described in my first communication (Jennings, 1908). By obser- vations on the living specimen it is not possible to obtain precise ‘measurements. It will be best therefore to begin our account with the statistical examination, taking up the observations on the living specimens by way of control. EFFECTS OF GROWTH ON A VARIATION POLYGON. If our suspicion that growth differences make up an important part of the observed variations in size of Paramecium is justified, then cultures rapidly multiplying and growing should be more vari- able than those that are stationary. To test whether this is true, two lots were removed from a rather old culture of descendants of D, in which inspection showed that the individuals were not multi- plying rapidly. One of these lots was killed at once, while the other Breadth in Microns. 412 JENNINGS—HEREDITY IN PROTOZOA. [April 24, was placed in fresh culture fluid. Twenty-four hours later this second set was found to be multiplying rapidly; a portion of it was then killed. The measurements of the two lots are given in Tables VI. and VII., while the facts are graphically represented in the Taste VI. Correlation Table for Lengths and Breadths of a Random Sample from a Culture of Descendants of D, in which Multiplication was not in Progress. For comparison with Table VII. (See also Deere 3.) (Row 3, Table XVIII.) Length in Microns. 148 152 156 160 164 168 172 176 180 184 188 192 ue, 200 204 208 212 S 34-12 2 ROE aes, aR | 9 © 36 3 2 as five. Se Ie ce 20 S 40 I I CER ee SP Se” Sac Se Me * 35 44 I AROS Week ian Pim Dime eee Sage eo. 22 a 48 tot 3 2 4 °3.°4. 3. 1. ee S52 I Ply CS 2 3.47 3 56 I 2 si 4 o 60 I sp 2 5 a I 1.4.0.4 3.121017 40° TS 13 0 Al 10 It.) 5 ee Length—Mean, 185.008 + .836u Breadth—Mean, 43.556 = .3902u St. Dev., 14.420 + .592¢ St. Dev., 6.748 + .276" Coef. Var., 7.704 + .324, Coef. Var., 15.490 + .651 Mean Index, 23.517 per cent.; Coef. Cor., .5955 + .0375. Taste VII. Correlation Table for Lengths and Breadths of a Random Sample of De- scendants of D, at a Time when Rapid Multiplication was in Progress. For comparison. with Table Vi. (See also Diagram 3.) (Row 4, Table XVIII.) Length in Microns. SSLELTSSSLSSSSSSSLLSIB ISS FBLL SE 32 2 36 1 TOP eee Se I 40 Il oto 353° 5 243 Tone 44 |\1 t TOE Lore ae 3°48 6.2 Oe 48 2.1 I 452 1 ties tha 124-5 a ee 52 Piz I I 1 2) § 4.350 56 | I Li 243003 (23) eee 60 I I Tig 2: 3 Tae 64 I I 68 ; 72 I 2032011314460 8 8 2 7 It This 2215 14147950 Length—Mean, 176.124 + 1.128" Breadth—Mean, 47.304 = .344" St. Dev., 23.360 + .707K St. Dev., 7.132 + 244" Coef. Var., 13.262 .461, Coef. Var., 15.057 = .526. Mean Index, 27.153 per cent.; Coef. Cor., .3945 + .0408. 1908. ] JENNINGS —HEREDITY IN PROTOZOA. 413 polygons of Diagram 3. It is evident that the variability has become much greater in the rapidly growing culture. The range of variation of length in the stationary culture is from 148 to 212 microns; in the growing culture it is from 104 to 220 microns, so that in the latter the range has almost doubled in extent. The coefficient of variation in length has likewise almost doubled, changing from 7.794 when the culture was stationary to 13.262 when it was growing. For breadth the range of variability has likewise increased consid- erably, though the coefficient of variability shows little change. The correlation between length and breadth has become considerably less in the rapidly multiplying culture, decreasing from .5955 to .3945. The mean length has slightly decreased, the mean breadth slightly increased, in the growing culture. 35 w ° 4 KR ~ 7 > Ber 6b iS] ° Pine od Zz Frequency in Percentages. nr Pr TE \' { \ 5 A L \ Pee OPE / AY | Lo NGG LOA S16) 282 SLAG E52): 204 AEF TSS OUOO S82 aaa Length in Microns. D1aGRAM 3. Polygons of variation in length for (a) a culture of de- scendants of D that is rapidly multiplying and (b) one that is not. The continuous line represents the rapidly multiplying culture of Table VII.; the broken line the stationary culture of Table VI. From this example it is clear that growth and multiplication may, and probably do, play a large part in determining the character and distribution of the variations, as well as in determining the mean dimensions and their correlations. We shall now attempt to deter- 414 JENNINGS—HEREDITY IN PROTOZOA. [April 24, mine as accurately as possible what this part is by a systematic study of growth. MATERIAL AND METHODS OF WorK. In order to exclude possible differences due to different ancestry, the study of growth was made with the progeny of a single individual for each of the two groups. Of the caudatum group a single individual D was iso- lated April 12. This individual was a large one, measuring approximately 250 microns in length. From it many cultures were made under various conditions, and all the results on growth in this group were reached with progeny of this individual D, save in cases where the contrary is expressly stated. In the same way the results for the aurelia group were reached with the progeny of a single individual c, unless otherwise noted. The method of work in the statistical study of growth was as follows: Numbers of dividing Paramecia of known descent were isolated and kept for varying periods, so that the age of the individuals was known to within a few minutes or even less. The individuals were then killed at different ages by the use of Worcester’s fluid, and measured. In this way the usual size at various ages was determined, and those variations in size that are due only to varying age of the individuals were excluded. By pursuing this method, an approximate curve of growth is obtained and the part played by growth in the observed variations elucidated; much light is in this way cast on many obscure matters. To persons who have worked with Paramecium it is unnecessary to point out the extremely laborious and time-consuming character of the operations required. Dividing specimens must be sought for with the microscope, among hundreds of their rapidly moving fellows; they must be taken up with the capillary tube, isolated, placed in culture fluid, and the time of capture noted. They must then, after lapse of the proper interval, be killed ~ and measured; this is.the smallest part of the work. To thus deal with individuals of known age by the hundred involves an incredible amount of exhausting labor, so that if the mathematical student finds in any stage the numbers employed not always as large as would be ideally desirable, he will realize that there is good reason for this. But it is hoped that the numbers used are amply sufficient, on the whole, for the purposes designed; the results are drawn from thé measurement of over 1,500 specimens of known age; together with control cultures of mixed ages in still larger number. Especially in the study of individuals that are very young (up to the age of half an hour or so), there is very great difficulty in dealing with large numbers owing to the fact that the time required for picking them out is very large in proportion to the amount of time they are to be kept, so that but few can be dealt with at once. Another great difficulty lies in the fact that to be strictly comparable, the sets of different ages must be chosen on the same day from the same culture; otherwise differences due to cultural conditions show themselves, confusing our results. No culture remains the same for two successive days, and the differences quickly show 1908.] JENNINGS—HEREDITY IN PROTOZOA. 415 themselves in the statistical results. The condition just mentioned cannot be absolutely fulfilled, but much effort was directed toward filling it as completely as possible, and where it could not be fulfilled, strict account of that fact was taken. The fixing and measurement of the specimens was done by the methods already described (p. 396). I. DESCRIPTION OF DIFFERENT STAGES OF GROWTH. First Stage: the Young Before Separation is Complete. In the earliest stage recognizable, the young Paramecium forms half of a dividing specimen. Before the constriction appears the macronucleus has become band-like, and the mother infusorian is shorter and thicker than the specimens not preparing to divide (see Fig. 2, a). The oral groove and other differentiated parts have become less marked. At the first appearance of the constriction the anterior and posterior halves still retain something of their charac- teristic form, and the body of the mother has extended a little (Fig. 2,b). The constriction does not pass squarely across the body, but is a little oblique, being farther back on the oral side (Fig. 2, c, d, e). As a result, when the two halves are measured separately, they will seem to differ in length, according to the place where the measure- ment is taken. Thus, if d, Fig. 2, is measured from the ends to the constriction along the oral side, the anterior half measures 96 microns, the posterior half 84 microns, while if the measurements are taken along the aboral side these proportions are exactly reversed. Measurements taken from one of the lateral sides give the same length for the two halves. The Paramecia may lie in various posi- tions and this obliqueness of the constricting groove is not always evident. Misled by this fact, I took great pains to measure the precise length of each half in a large number of cases, finding con- siderable differences, though without any marked preponderance of either half. But I am now convinced that in early stages of fission the most accurate measurements of the young are to be obtained by considering each to be one half the length of the two together. The breadth of the two halves frequently differs a little, the posterior half being at times slightly broader than the anterior half. As the constriction deepens, the two halves lengthen (Fig. 2, btof;g tol, etc.). This lengthening progresses with the advancing 416 JENNINGS—HEREDITY ib i Fic. 2. Dividing specimens of the caudatum form, descended 0 individual D. Note the increase in length and decrease in breadth ; constriction deepens. Anterior ends above. All XX 235. 1908 ] ‘ JENNINGS—HEREDITY IN PROTOZOA. 417 constriction until the two halves separate. This lengthening is clearly evident in the figures and in the correlation table giving depth of constriction with length of body (Table XI., page 441). As Table XI. shows, there is a period at the beginning, before the constriction reaches a depth of about 10 microns, when there is little relation between the length of the body and depth of constriction, showing that in this period the halves have not yet begun to lengthen. We may therefore take the length of the young at this period as that characteristic for the young individuals in their earliest recognizable condition, before growth has begun. By dealing with these alone we are able to compare the variability of the young with that of the adults, or with random samples including allages. In the further treatment, therefore, the measurements of the unseparated young are divided into two classes: (a) those before lengthening has begun; (b) those after lengthening has begun. (a) The Unseparated Halves before Lengthening Has Begun.— Studies were made of the young of three lots of the caudatum group (descendants of the individual D), and of two lots of the aurelia group (descendants of the individual c). Each “lot” included individuals taken on the same day from the same small culture. In most of the lots there were examined: (1) The unseparated young before growth had begun; (2) the unseparated young after growth had begun; (3) a random sample, including all sorts of individuals found in the culture. The results of these measurements are given in Table VIII., page 418. (1) The caudatum Form (Descendants of D).—The most thorough study was made of lot 1, of the caudatum group; the results there reached are typical, and perhaps more reliable than any others, owing to the large numbers examined. We shall therefore make the results on this lot the basis of our discussion, afterward bringing out points of difference and resemblance shown in the other lots. From this lot 1, I measured 313 dividing specimens, which, of course, included 626 unseparated young; a random sample of 200 individuals not dividing was likewise measured. A correlation table for the 313 dividing specimens, giving the depth of the constriction below the general body surface and the length is given on page 441 418 is for convenience of reference in the text. Taste VIII. Mean Dimensions and Constants of Variation for Youngest Stages, in Com- JENNINGS—HEREDITY IN PROTOZOA, [April 24, The column headed which fuller data are given on the lot in question. A “ Lot” consists of Table X., page 428. Os 3 A. Bhi std Seat vi yciin BE & Z orm). a5 3 i Aah Ae Deviation. | Variantanal 1| Lot 1. Young halves, where depth of con- striction is 4 or less ..... 262! 9 | 87.848+-.278| 4.716+-.197| 5.368.224 2) Lot 1. Halves, where depth of constriction is more than 4jl........sceceee 364 | (62) | 93.033+.355| 7.104-+.251| 7.636+.271 3 Lot 1. Random sample...... 200} 14 |199.960--.740 | 15.528-+.524| 7.765-+.263 4| Lot 2. Halves, where depth of constriction is less than & breadth....... 80 | (43) | 82.600+.468| 4.394+.332| 5.320.402 5 Lot 2. Ad halves of divid- ing SpeciMeNS.........sss00 124 | (42) | 85.774+.593| 6.924+.420| 8.072+.492 6) Random sample..........00++ 200| 30 |184.100-+.776| 16.264+.548| 8.834+.300 7, Lot 3. Halves, depth of constriction less than 1 breadth.) ......:ssnsesaee 84| (44) | 83.810+.498| 4.782++.352| 5.706.421 8, Lot 3. Adults 24 hours old.) 300/ 41 /168.532+.419 | 10,768-+.296| 6.389.175 B. Progeny of ¢ (aurelia form). g Lot 4. Halves, where depth of constriction is less than ¥ breadth...... 132 | (47) | 51.868+.325 | 3.912.190} 7.541.445 10| Lot 4. Halves, lengthening , begun (constriction more than &% breadth)........... 106 | (63) | 60.692+.527| 5.684.372] 9.365+.613 11| Lot 4. Random sample...... 225| 49 |114.163+.784 | 17.443+.555 | 15.279-+.497 12| Lot 5. Halves, where con- striction is less than DEORE oi ak dsductensands & 76| 48 | 56.666+.425| 3.889+-.302| 6.862-+.533 13} Lot 5. Random sample...... 100| 50 |114,033+.820 | 12,140+,580 | 10,646+.513 14| Lots 4 and 5. All halves where constriction is less than Y% breadth (com- bination of rows 9 and 1 Ee MEU ce Sacaaicess 208| — | §3.622+.300| 4.535+.212| 8.459+.398 (Table XI.). In 131 of these specimens the constriction had sunk less than one unit of the micrometer (4 microns) below the surface, while in the other 182 the depth of the constriction was greater. We may take the 131 specimens in which constriction had barely begun JENNINGS—HEREDITY IN PROTOZOA. 419 1908. | TABLE VIII.—Continued. parison with Random Samples and Adults. (The column headed “ Row ” “Table” gives the number of a table found elsewhere in the paper, in specimens all taken from the same culture on the same day.) Compare Breadth. Ratio of piney to Coefficient of Corre- ength, or lation Mean Standard Coefficient of Mean Index - Deviation. / Variation. Per Cent. g | 55.480-+.297 5.040.210 | 9,082+.382 63.136 .6546+.0337 49.540-+.215 4.296.152 8.671 +.309 53.592 —.0938-+.0496 50.220-+-.308 6.468.218 12.877+-.441 25.114 .6064-+,0302 50.700+-.364 3.532.260 6.769+.513 61.530 1048+-,1055 50.388+.307 3.584+.217 | 7.112+.433 59.166 —.1136+.0840 46,.020+.251 5.256+.177 11.421-+.390 25.084 .4282+-,0389 65.716-+.706 6.784.499 10.322-+.768 78.563 .2215-+.0999 40.320-++,230 5.892.162 14.615-+.411 23.899 .5496-+.0272 34.850-+,.287 3.453.203 9.911.587 67.246 .6502+-.0479 34.590+.383 | 4.147-£.273 11,989--.797. 57.296 .3100-++,0837 34.207+.241 5.363.171 15.683-+.511 30.177 .6757-+.0244 45.263-+.597 5.463.423 12,071-+.947 79.806 .6744-++.0597 47.300.437 6.490+.310 13.720+.667 41.455 8152+.0226 38.653 +.437 6,607-+.310 17,089+.822 71.835 .7476+.0292 as types of the earliest stage of fission, and their 262 halves as young Paramecia in the earliest stage. The lengths and breadths of these 262 halves are given in Table IX. The constants derived from the measurements of these, as well as from the measurements of the 364 420 JENNINGS—HEREDITY IN PROTOZOA. [April 24, Taste IX. Correlation Table for Length and Breadth of 262 Unseparated Halves of Dividing Specimens, in which the Depth of Constriction was less than four microns. All descendants of the single individual D, and taken from the same culture on the same day. Length in Microns. 78 80 82 84 86 88 90 92 94 96 98 I00 102 3 5 44 2. 2 4 5 48|2 6 12 °6 2 2 38 S 52 PAT Vaal CD ae” Wee (gia Me 54 i Oe Oe AW BOTAN BOCA Te abe (2 ceN ae 94 “= 60 Pas o> Acai” SUR: Ca © 8 ee Yi Me Aa MM 44 S 64 2 Py «ae a ae 22 Z 68 2 2 4 & 72 2 2 ~Q OPE NEB. pear rinsis 2. 16 BR RE ay Be OR BO BO Ee Be ae 2 |262 Length—Mean, 87.848 + 278u Breadth—Mean, 55.480 + .2074 St. Dev., 4.716 & .197¢ St. Dev., 5.040 = .2TOu Coef. Var., 5.368 + .224 Coef. Var., 9.082 + .382 Mean Index, 63.136 per cent.; Coef. Cor., 6546 + .0337. halves in which lengthening had begun, and of the random sample, are given in the first three rows of Table VIII.* We will for the present limit the discussion to the relations shown by comparing the youngest stages (row 1) with the random sample (row 3) which consists mainly of adults. The following important facts are shown: 1. The mean length of the youngest stages of the new individuals is considerably Jess than one half of the mean length of the indi- viduals that are not dividing. The mean length of the young is 87.848 microns, while that of the individuals not dividing is 199.960 microns, or 24.264 microns more than twice the mean length of the young individuals. This remarkable relation will be taken up later, in discussing the measurements of dividing specimens (page 443). 2. The mean breadth of the youngest stages is slightly greater than that of adults not dividing—s5.480 microns, in place of 50,220 microns. ‘ °In Tables VIII. and IX. the measurements were made and the constants were first computed, for the entire dividing specimens. The constants for the halves were of course readily obtained from these; they are the same, save that the mean and standard deviation for length are halved, and the mean index is doubled. The computation of the probable errors was based on the number of dividing specimens, not on the number of halves. eae JENNINGS—HEREDITY IN PROTOZOA. 421 3. The mean index, or ratio of breadth to length, is considerably more than twice as great in the young as in the adults; in the former it is 63.136 per cent.; in the latter 25.114 per cent. 4. The variability in length is less in the earliest stages of the young than in the individuals that are not dividing. In the former the coefficient that measures the variability is but 5.368, while in the latter it is 7.765. 5. The variability in breadth is likewise much less in the youngest stages—the coefficient being 9.082 in place of 12.877. 6. The correlation between length and breadth is nearly the same in the youngest stage as in the random sample, being .6546 in the former, .6064 in the latter. From the other lots smaller numbers were examined. These gave on the whole similar results, though with certain significant differences. The facts are as follows: From lot 2 (descendants of D), 124 halves were obtained. On account of the small number, I threw together all in which the depth of the constriction was less than one fourth the breadth, and consid- ered these the earliest stage (the depth of constriction and length are given for the entire dividing specimens in Table XLII., appendix). There were thus obtained eighty young individuals (dimensions for the entire dividing specimens in Table XLIII., appendix). It is evident that this lot includes individuals varying more in age and growth than in lot 1, since in lot 2 we have included those having a much greater depth of constriction. The results are shown, in comparison with a random sample of the same lot, in rows 4 and 6 of Table VIII. The facts are in the main parallel with those for lot 1. As compared with the random sample, the mean length of the young is less than one half, the mean breadth a little greater, the mean ratio of breadth to length more than double, the coefficients of variation for length and breadth much less. A striking differ- ence between this set and the young of lot 1 is that in the present case the correlation between length and breadth has decreased to such an extent that the coefficient computed (.1048) is without sig- nificance, being less than its probable error (.1055). This is due, as we shall clearly see later, to the fact that we have included in the 422 JENNINGS—HEREDITY IN PROTOZOA. [April 24,. young of row 4 individuals older (constriction deeper) than in those of row I. From a third lot of descendants of D, 154 halves were obtained ; in 84 of these the constriction was less than one fourth the breadth. Unfortunately no random sample of this culture was preserved. But 300 individuals just twenty-four hours old were taken from it for other purposes, and the young halves may be compared with these (rows 7 and 8, Table VIII.).* It should be noted, however, that the adults of row 8 had been kept for twenty-four hours in.a rather small quantity of water, where food was relatively scarce, so: that they were smaller than would have been the case if they had lived throughout under the same conditions as the dividing specimens. In general, the same relations are shown here as in the other lots. A striking peculiarity is the great breadth of the young halves. (65.716 microns), as compared with that of the adults (40.320 microns), so that the ratio of breadth to length (the “ mean index ’”’) is more than three times as great in the young as in the adults. (78.563 per cent. in the former, 23.899 per cent. in the latter). Owing to the inclusion of older halves, in which lengthening has begun, the correlation between length and breadth is again low (.2215 + .0999). (2) The aurelia Form (Descendants of c).—Two lots of divid- ing specimens of the auwrelia form were examined, the first including 132 halves in which lengthening had hardly begun, the second 76. The constants for these, in comparison with random samples of those not dividing, are given in rows 9 to 14 of Table VIII. These show the same relations that we have already seen in the caudatum group, with one exception. In the smaller collection (lot 5), the mean breadth of the halves was a little Jess, instead of greater, than that of the random sample. In this culture the animals were extra- ordinarily broad, the mean ratio of breadth to length in the random sample being 41.455 per cent., in place of the usual ratio of about 30 per cent. This was due to the fact that these animals had been placed twenty-four hours before in a rich nutrient solution and had “The dimensions of the entire dividing specimens of which row 7 are the halves are given in Table XLIV. of the Appendix; the dimensions of the 300 just twenty-four hours old are given in Table XLI. 1908 J JENNINGS—HEREDITY IN PROTOZOA. 423 become very plump. The point of interest is that the breadth of the young individuals in the earliest stages tends toward a constant dimension, becoming greater when the adults are thin, less when the adults are plump. Outlines of dividing specimens, and of those not dividing, from this culture, are shown in Fig. 3, a to f; the great difference in breadth is noticeable. UO0b8E Fic. 3. Outlines of specimens of the aurelia form (descendants of c), from Lot 5, Table VIII. c to f, Successive stages of fission. Note the greater breadth of the specimens not dividing (a and b). Same magnifica- tion as Fig, 2. (235 diameters.) In row 14, Table VIII., are given the constants for all the young halves examined of the aurelia group; that is, for the sum of rows g and 12. The coefficients of variation are, as might be expected, increased by adding these two dissimilar groups. The fact that the correlation between length and breadth is likewise increased, as com- pared with what we find in either group taken alone, might not, perhaps, be anticipated. These changes in variation and correlation are environmental effects, to be studied later. (b) The Unseparated Halves after Lengthening Has Begun.— As we have already seen, the length of the halves increases as the constriction deepens (see the correlation tables for length with depth of constriction, Nos. XI. (page 441), XLV., XLVI.; compare also the outlines of dividing specimens, Figs. 2 and 3). The coefficient of correlation between depth of constriction and length is, for the 626 halves of Table XI., .6882; with each increase of 10 microns in depth of constriction the length increases 4.30 microns. If we include only the individuals in which lengthening has clearly begun (thus omitting the uppermost row of Table XI.), we find that for 424 JENNINGS—HEREDITY IN PROTOZOA. Capel ub these 364 halves the correlation between depth of constriction and length is greater, amounting to .7818; while the increase in length with each I0 microns of increase in depth of the constriction is 5.598 microns. ; While the length thus increases, the breadth decreases. This is evident on inspection of Table XII. The correlation between depth of constriction and breadth of body is therefore negative; its coeffi- cient, in the case of Table XII., is —.5232. With each increase of 10 microns in the depth of constriction the breadth of body decreases 2.630 microns. If again we take into consideration only the 364 halves in which lengthening has decidedly begun, omitting thus the uppermost row of Table XII., we find that the correlation decreases to — .3316, and the decrease in breadth for an increase of 10 microns: in depth of constriction is but 1.252 microns. This appears to indi- cate that a large part of the decrease in breadth occurs in the first stages of constriction. If we compare with the means of the 262 halves in which length- ening has not begun, the means of the 364 in which lengthening has begun (Table VIII., rows 1 and 2), we find that the length has increased from 87.848 to 93.033 microns, while the breadth has - decreased from 55.480 to 49.540 microns. If we examine the means at successively older stages, we find, of course, greater differences. Thus, when the constriction has reached a depth of 36 microns, the 10 specimens in that stage show the mean length increased to 101.200 microns, while the mean breadth is but 46.400 microns. Similar relations are to be observed if we compare the means of the younger and older sets of each lot shown in Table VIII. Since, while the length is increasing, the breadth is decreasing, the growth tends to decrease the correlation between length and breadth or even to make it negative. Thus, while in the stage before lengthening has begun (row 1, Table VIII.) the correlation is .6546, in the 364 specimens of the same lot, after lengthening has begun the correlation has decreased to — .0938 (row 2, Table VIII.). In a second lot, containing 124 halves, when we throw all the halves together the coefficient of correlation between length and breadth becomes — .1136 (row 5, Table VIII.). In the aurelia form, 106 — halves after lengthening has begun give a positive correlation between 1908.] JENNINGS—HEREDITY IN PROTOZOA. 425 / length and breadth of .3100 (row 10, Table VIII.). Why there should sometimes be a slight positive correlation, sometimes a nega- tive one, at this stage, will be discussed in the section where we deal with the various factors determining correlation. A variation polygon for the youngest stage of lot 1 of Table VIII. is shown in Diagram 4, p. 440, at a. The changes above set forth from statistical data were in a num- ber of cases observed in living individuals. These observations give a number of additional points of importance, so that they will be described. The facts, as illustrated mainly by a typical specimen of the aurelia form, are as follows: Some time before fission the body thickens and becomes shorter, taking the form shown at a, Fig. 2, orc, Fig.3. The form and dimen- sions differ very noticeably from those of the specimens not preparing to divide. How long before the appearance of the constriction these preparatory changes in form begin it is not possible to say, because it is not possible to distinguish with certainty whether a given speci- men is to divide or not until we can see the constriction, and this is at a relatively advanced stage of the process. At the time the con- striction first appears the anterior and posterior halves still differ in form, though they are losing their characteristic features. As the constriction deepens the two halves become longer (Fig. 2, b to f, Fig. 3,c tod). A specimen of the aurelia form (descend- ant of c) was at about the stage shown at d, Fig. 3, at 12.05; each half measured very nearly 80 microns in length. . Ten minutes later (at 12.15) the connecting portion had become smaller, while the two halves had lengthened, so that each measured about 85 microns in length. The anterior half was more pointed and slightly more slender than the posterior half (f, Fig. 3) ; this is regularly the case. Six minutes later (at 12.21) the posterior half measured about 90 microns, the anterior half 94. The connecting band was now extremely slender. Five minutes later (at 12.26) the two halves separated. The anterior half was still clearly distinguishable from the posterior one by its pointed, somewhat pear-like form. It measured 100 X 44 PROC. AMER. PHIL. SOC, XLVII. 190 BB, PRINTED JANUARY 9, 1909. 426 JENNINGS—-HEREDITY IN PROTOZOA. [April 24, microns, while the posterior half was shorter, but thicker, measuring 96 X 52 microns. The succeeding changes of form will be described in the next section. Thus from the condition shown at d, Fig. 3, to the completion of fission a period of twenty-one minutes elapsed. From the earliest appearance of the constriction the time till separation is usually a little more than one half hour. Second Stage: the Young Immediately after Fission up to the Age of Ninety Minutes. . Observation of Living Specimens.—Immediately after separation of the two halves, growth occurs rapidly, and the shape changes, both halves becoming more pointed at both ends. In the specimens of the aurelia form under description at the close of the last section, the posterior half had two minutes after fission increased in size from 96 X 52 microns to 104 X 48 microns.. Eight minutes after separa- tion both halves measured 112 microns in length, so that they had during that period increased respectively 12 and 16 microns in length. The difference between anterior and posterior individuals was still marked. Now followed a period of slower growth. At 12.53, twenty- seven minutes after division, each half measured approximately 120 microns in length. They had taken nearly the characteristic adult form and it was no longer possible to distinguish the anterior product from the posterior one. At 2 P. M. (one hour and thirty-four minutes after separation) the length was about 135 microns and the progeny were similar to the adult specimens of the aurelia form. Thus, at the time of separation the two individuals have some- what more than half the adult length; they grow rapidly at first, then slowly, and in an hour and a half have reached nearly the adult size. (As later statistical studies show, growth continues for a long time still.) Observation on the growth of living specimens of the caudatum form gave a parallel series of phenomena (see Fig. 4). Thus, in a descendant of D, the length of each half at the time of separation 1908. | JENNINGS—HEREDITY IN PROTOZOA. 427 was about 120 microns; width 48 microns. Five minutes later the length had increased to 132 microns, while the width was still 48 microns. Nine minutes later the length of the anterior product was 148 microns; that of the posterior product 144 microns. The width had decreased a little; it was now about 44 microns. After thus increasing in fourteen minutes by nearly one fourth the original length, growth became less rapid. Forty minutes later (fifty-four minutes after separation) the length was about 156 microns. During two succeeding hours no increase in length could be detected. The form was that of the normal adult, though the adult size was not yet reached. - We may summarize as follows: Some time before fission (per- haps a half hour) the body shortens and thickens, so that each half is at first less than half the adult length. As the constriction deepens the two halves grow longer, till at the time of separation they are somewhat more than half the adult length. For five to twenty min- utes after separation growth in length is very rapid, while the thick- ness remains stationary or decreases. ,Then follows a period of several hours of slower growth, till the adult size is reached. This somewhat indefinite account, based on the observation of living specimens, will now be supplemented by a statistical investi- gation of a large number of individuals at various ages. The main results of this statistical investigation are brought together in Table X. (c) Age o to 5 Minutes (Table XXIX.).—A large number of dividing specimens, all descendants of the individual D (caudatum form), were removed from a rapidly multiplying culture and kept for from o to § minutes in a watch-glass of culture fluid, then killed and measured. The method of work was to spend five minutes in picking out dividing specimens with the capillary tube and placing them in the watch-glass; at the end of the five minutes the lot was killed. Then other lots were prepared in the same way. In each lot killed, therefore, there occurred specimens that were in the early stages of fission ; others that had separated at the moment of removal and were hence just five minutes old; and all stages intermediate between these two. All together, 62 unseparated pairs and 59 sepa- rated individuals were secured in this way. ‘The latter set consists of individuals from 0 to 5 minutes old (reckoning from the moment 428 JENNINGS—HEREDITY IN PROTOZOA, TABLE X. [April 24, Dimensions and Constants of Variation for Paramecia of Various Ages, in taken from the same culture on the same day. The lots where identical column headed “ Row” elsewhere, in which fuller data are given on the lot in question.) is for convenience of reference. The column Row. - A. Progeny of D (Caudatum Form). Lot 1. Youngest unseparated halves, constriction begin- nin Lot 1. begun Lot I. Halves, lengthening eee meee eee new esses nseeeeeee Lot 2. From beginning of con- striction to 5 minutes after SOPAratiONn..0cs.4.-snneemrenaaes Lot 2. o to 5 minutes after separation Lot 2. Lot 6. Lot 6. Lot 6. Random sample.......... Age 0 to I9 minutes, .. Age 18 to 28 minutes... Age 35 to 45 minutes... Lot 6. Age 75 to 90 minutes... Lot 6. Age 0 to 90 minutes (sum of rows 7-I0)........... Lot 6. Random sample.......... Lot 7. Age o to I9 minutes,.... Lots 6 and 7. All o to Ig (sum of rows 7 and I3)...... Lots 6 and 8. Age 18 to 28 minutes (sum of row 7, and of 57 of another lot).......... Lot 9. Age 3 to 4 hours......... Lot 9. Age 4.20 to 5 hours,... Lot 9. Age 3 to 5 hours (sum of rows 16 and 17) Lot 9. Random sample. ........ Lot 10. Age 12 hours............ Lot 10. Age 12 hours (same as row 20, but omitting 2 SMBUESE)! cpavewede eve pey ee sds see Lot 10, Age 18 hours..,......... Lot 3. Age 24 hours............. Lot 3. Early fission, a of constriction less than Y% breadth 20 Ns taaeasemente ser be Lot 1, Early fission, constric- rere eee eer er ee tion 4 or less Number of Individuals at 106 195 Table. Length. Standard Deviation in Microns. Mean in) Microns. Coefficient of Variation. 87,.848+ .278| 4.7162 .197 7.104 15.528 .251 524 93.033 .355 199.960 .740 .718|14.400+- .508 92.940 14.780+- 16,264 .916 548 13.856-+1.348 6.480+ .440 7.512 .716 9.6484 .712 107.660--1.296 184,100-+ .776 128,000+1.908 143.348+ .624 149.920+1,012 161,524--1.004 14.464+ .584 12,596+ .600 15.394-41.176 147.544+ .824 184.680+ .848 134.256+1,663 131.872-+1,288'15.176+ .g12 143.82 + .544) 8.296+ .384 149.636+ .688 9.856 .488 186.736+ 653 9.416+ .460 168.384-+1.028 20.904 .727 176,124+1,128 23.3604 .797 188.988+- .996 12.612-+- | | .752, 9.388 .380 11.844-+ .419|10,768-+- -704. 190,424 199.048-++ 168,532-+ 531 +552 .629 167.620+ .996| 9.564 .704 175.696+ .556) 9432+ .393 5.308+ .224 7.636+ 7.765 271 .263 15.4942 13.729 8.834+ 559 868 +300 10,825-+ 1.066 4.5214 .309 5.010 .479 5.974 .441 9.803-+ .399 6.821% 327 11,.468+ , 11 ,§07253 5.769 6.587 . §.043+ . 12.415+ . 13.262 . 6.672 ; 4.930> . 5.949+ . 6.389+ . 5.706 , 5.368+ . 112-168 132-176 164-216 132-216 104-220 136-216 164-216 168-228 140-200 152-192 156-240 1908. | JENNINGS—HEREDITY IN PROTOZOA. Comparison with Random Samples. with those of Table VIII. are numbered the same as in Table VIII. The headed “ Table” gives the number of a table found in the appendix or TABLE X.—Continued, (Each “ Lot” consists of specimens 429 Breadth. g % $ 3 A s oS Coefficient of Mean in Standard Cocthirrenét Range of easou Correlation. Microns: Deviation in VariaGon: Variation § m4 & 4 fs Microns, : in Microns. | & 55.480-+-.297 5.040-+,210 9.082+-.382 44-72 63.136 .6546-+.0337 49.540+.215 | 4.296-4.152 8.671+.309 40-68 53.592 | —.0938-+.0496 50,220+.308 | 6.468+.218 | 12,877+.441 36-72 25.114 .6064+,0302 48.852+.210 | 4,216-+.149 8.633.307 36-64 54.080 | —.3625-+.0433 46.372+-.332 | 3.804+.236 | 8.200+.524 | 36-56 | 44.047 | —.3138+.0792 46,020-+-.251 | 5.256.177 | I1.421-+.390 36-60 25.084 .4282+,0389 60,168+..788 | 5.712+.556 | 9.495+.933 | 52-76 | 47.573 | —.0337+.1375 54.284+.364 | 3.788-+.260 6.976+.478 48-64 37.921 .1937-.0927 55-840+.636 | 4.724+.452 | 8.461.813 48-64 37.296 | .2799-.1243 54.192+.600 | §.752+.424 | 10,617+.790 | 40-68 | 33.558 | .5232+.0756 55.544-+.308 | 5.416-+.220 9.748.397 40-76 38.038 | —.0844-+.0566 64.880+.580 | 8.624+.412 | 13.292+.645 44-88 35.131 .6469+.0392 46.768-+.408 | 3.792-+.288 8.108+-.623 36-52 35.616 | —.2546+.1010 51.872+.680 | 7.980.480 | 15.382-+.946 36-76 40.028 | —.2476+.0798 50.832+.320 | 4.900+.228 | 9.640+-.451 36-64 | 35.438 | .1319-+.0644 51.568+.322 | 4.752.236 9.212+.459 40-64. 34.546 .3201+.0628 60,168+-.360 | 5.224+.256 8.679.428 52-76 32.225 5557+.0478 §5.916-+.324 | 6.588.229 | 11.785-+.416 40-76 33.372 .7132-+.0242 47.364+.344 | 7.132.244 | 15.0574+.526 | 32-72 27.153 | .3945-+.0408 62.796+-.464 | 5.872+.328 9.350+.526 48-80 33.275 .4868 + .0602 63.156+.443 | 5.536+.313 | 8.763+.500 | 48-80 33-197 | .3474-+.0704 56.496+.292 | 4.428+-.108 7.837.367 48-68 28.427 4304.05 36 40.320-+-.230 | 5.892+.162 | 14,615+.411 28-56 23.899 .5496-+.0272 65.716+.706 | 6.784.499 | 10.322-+.768 48-80 39.286 .2215-+.0999 55.480+.297 | 5.040+.210 | 9,082-+.382 44-72 31.568 .6546-+.0337 430 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE X.—Continued. 34 } Length, e A. Progeny of D (Caudatum Ss re chia Z form). Epo for Mean in Standard Coefficient of | Range of Za Microns, Deviation in Variation. | , Variation = Microns. in Microns. 26 | Lot 1. Fission, all stages but Cares a sohuss asonestdomveatenes 182| 62 |186,066+ .710| 14.208-+.502| 7.636-+.271 | 160-224 27 | Lot 1. Random sample ......... 200} 14 |199.960+ .740| 15.528-+-.524| 7.765+.263 | 148-240 28 | Lot 1. Largest specimens of random sample, all more than 196:1009.\..ccsegscsosuses 134; — |208.268+ .566) 9.720+.400 196-240 29 | Lot 1. Combination of early fission with largest of random sample (sum of rows 25 and BB Ys donuncey vad ven seaeeeointeeeMe 264) —- |192.108 18.904 30 | Lot 2. Early stages of fission..| 40] 44 |165.200+ .936| 8.788+.664| 5.320-+.402 | 152-192 31 | Lot 2. All stages of fission ..... 62) 42 |171.548+1.188] 13.848+-.840| 8.072+-.492 | 144-212 32 | Lot 2. Random sample.......... 200} 30 |184.100-+ .776| 16.264+.548| 8.834+-.300 | 140-216 B. Progeny of ¢ (aurelia form). 33 | Lot 4. Early fission, depth of constriction less than 4% breadth... 5i6skcegyueie eee 66! 47 |103.737+ .650| 7.823+.379| 7.541+.445 83.3-126.7 34 | Lot 4. Later stages of fission...) 53) 63 |121.383-+1.053| 11.367+.743| 9.365-+.613 | 100-156.7 35 | Lot 4. Random sample.......... 225) 49 |114.163+ .784| 17.443+.555 | 15.279-+.497 |73.3-160 36 | Lot 5. Early fission............... 38) 48 [113.333 .850) 7.778+.603| 6.862+.533 /93.3-126.7 37 | Lot 5. Random sample.......... 100} 50 |114,033+ .820) 12.140+.580 | 10.643+.513 |86.7-146.7 38 | Lots 4 and 5. All in early fis- sion (sum of rows 33 and 36).|104) -— |107.243-+ .600; 9.070+.423/ 8.459-+.398 83.3-126.7 _ of separation of the two halves). > The measurements of these 59 young specimens are given in Table XXIX., while the polygon of variation for length appears at b, Diagram 4. For control, Table XXX. gives the measurements of a random sample of the culture from which these young specimens were selected. The constants deduced from the measurements of the young and of the random sample are shown in Table X., rows 4 to 6. The following are the important facts which result from the examination of the young, in comparison with the adults (rows 5 and 6, Table X.). 1. The mean length of the young (0 to 5 minutes old) is consid- erably more than half that of the culture as a whole, being 107.660 microns as compared with 184.100 microns. Of course, the culture 431 1908. | JENNINGS—HEREDITY IN PROTOZOA. TABLE X.—Continued, Breadth. By 8 az Range ot |e 9 8y| Coniston. M ; Standard Coeffici f ange o' CI by orrelation. Micon, | Deriatonin | “Variadon. | Variation | E218 49.540+.215 | 4,296,152 8.671.309 40-68 26.796 | —.0938-+.0496 50.220+.308 | 6.468.218 | 12.877-.441 36-72 25.114 .6064+-,.0302 52.360+.348 | 5.964-+.246 40-72 4681 +-.0455 53.908 5.752 .0350+.0415 50.700+.364 | 3.432-+.260 6.769+.513 48-80 30.765 .1048+.1055 50.388-+.308 | 3.584-+.216 7.1LI+.433 40-60 29.583 | —.1136-+.0840 46.020+.251 | 5.256-+.177 | 11.421+.390 36-60 25.084 .4282+,0389 34.850-+.287 | 3.453-+.203 | 9.911-4.587 | 26.7-43.3 | 33.623 | .6502-+.0479. 34.590+.383 | 4.147+.273 | 11.989+.797 | 26.7-46.7 | 28.648 .3100+,0837 34.207+.241 | 5.363.171 | 15.683+.511 20-50 30.177 .6757+.0244 45.203+.597 | 5.463.423 | 12.071+.947 | 33.3-56.7 | 39.903 | .6744+-.0597 47.300+.437 | 6.490+.310 | 13.720+.667 | 36.7-66.7 | 41.455 8152+.0226 38.653+.437 | 6.607+.310 | 17.089-+-.029 | 26.7-56.7 -7476+,0292 as a whole contains a large number of young specimens, so that the mean of the adults would be greater than that of the random sample. 2. The mean breadth of the young is almost exactly the same as that of the culture as a whole. 3. The relative variation in length is much greater for the young than for the culture as a whole, the coefficient being 13.729 for the former as compared with 8. 834 for the latter. Moreover, the coeffi- cient of variation is almost three times as great as in the very young- est stages before separation (Table X., row 1), or in the first stages of fission (Table X., rows 25, 30, 33, 36). This great variability of the young at this age indicates that they are growing rapidly in length ; those five minutes old are considerably longer than those that have just separated, so that when all are taken 432 JENNINGS—HEREDITY IN PROTOZOA. * [April 24, together the variation is great in proportion to the mean length. While the statistical data are themselves open to other interpretations, observation of the changes in living individuals, as described earlier, shows that this explanation is the correct one. The absolute variation of the young, as shown by the standard deviation, is less, as might be expected, than that of the culture as a whole, though the difference is not great. 4. The variation in breadth, both absolute and relative, is less in the young than in the culture as a whole. The fact that it is still considerable perhaps indicates that changes in breadth are taking place during growth. To this we shall return immediately. 5. The correlation between length and breadth is negative in the young, while in the culture as a whole it is positive. In the former the coefficient is — .3138; in the latter it is + .4282. The fact that the correlation is negative in young specimens (greater length associated with less breadth) indicates that while the animals are growing in length they are becoming more slender. With an increase of Io microns in length the decrease in breadth is .757 micron. If we group together the unseparated halves (124 in number) with the separated ones (59), we find that the negative correlation between length and breadth is still greater, becoming ' — .3625 (see row 4, Table X,). 6. The mean ratio of breadth to length (“ mean iden ”) is much greater in the young than in the random sample. In the former the breadth is 44.037 per cent. of the length; in the latter but 25.084 per cent. If we include the unseparated halves with those under five minutes old, the breadth is 54.080 per cent. of the length (row 4, Table X.), while in the unseparated halves alone it is 59.166 per cent., and in the earliest stages of the unseparated halves it is 61.530 per cent. (see Table VIII., rows 4 and 5). There is thus a steady reduction of the ratio of breadth to length; to this is due the negative correlation of the two, when those of different ages are thrown together. (d) Age oto 19 Minutes (Tables XXXI.and XXXII.).—From another culture composed of descendants of the individual D, speci- mens were taken on June 14 and kept to several different ages. The 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 433 various ages and measurements are given, with those of a random sample of the culture in lot 6, Table X. The first set taken consisted of but 24 specimens, aged from o to 19 minutes. Though the number is small it is worth while to work out the constants for comparison with other stages in this same culture; it must be remembered that it is extremely difficult to get large numbers at any one time of individuals so young. The meas- urements are given in Table XXXI., while the constants are shown in row 7, Table X. For comparison with these a second lot of the same age, but containing 39 specimens, was taken from the same culture two weeks later. The measurements are given in Table XXXII. ; the constants in row 13, Table X. The constants for the two sets taken together (63 specimens aged 0 to 19 minutes) are given in row 14, Table X. Comparing these with the specimens but 0 to 5 minutes old, we find that the mean length has increased by 36 to 40 microns. The breadth is about the same in one of the lots (row 13, Table X.), but is much greater in the other (row 7). This difference is due to environmental effects. The coefficient of variability in length shows a decided decrease, indicating that growth is relatively more rapid during the first five minutes than later. The correlation between length and breadth is, as might be expected, negative in the sets 0 to 19 minutes old, as it was in the set still younger. A number of specimens were killed at precisely known ages, and the measurements taken. Thus, from lot 7 (row 13, Table X.) a typical pair of young at the moment of separation measured I10 X 52 microns. At the age of one minute the two members of a pair measured each 124 X 52 microns; at two minutes another pair were each 120 X 52 microns. At three minutes one member of a pair measured 120 X 48 microns, the other 124 & 44. At five minutes the lengths of the two resulting from a certain fission were respect- ively 124 X 48 and 112 X 44 microns. Five specimens kept till they were precisely nineteen minutes old measured respectively 160 X 48 microns; 160 X 44; 152 X 36; 152 X 40; 15644. The mean di- mensions were thus 156 X 42.4 microns. Outlines of individuals from o to 19 minutes old, showing the 434 JENNINGS—HEREDITY IN PROTOZOA. [Apeiliags relative sizes, are given in Fig. 4. These may be compared with the adults of this race, a to c, Fig. 1. 50086 BONE Fic. 4. Young Paramecia, descendants of D (caudatum form), from immediately after separation to the age of 19 minutes. a has just separated; b, c and d are two to three minutes old; i and 7 are 19 minutes old; the others are intermediate. These should be compared with the adults a to c of Fig. 1 (page 403), which are drawn to the same scale. All X 235. (e) Age 18 to 28 Minutes (Tables XXXIII. and XXXIV.).— The first lot of this age (row 8, Table X.) contained 49 specimens (Table XXXIITI.) and came on the same day from the same lot as the first lot of 24 of the preceding stage, so that the two are strictly comparable. The mean length has increased in the period of about thirteen minutes by nearly 16 microns, while the mean breadth has decreased 7 to8 microns. The ratio of breadth to length has decreased almost 10 per cent. The correlation between length and breadth is in the present lot positive though small (.1937). If we should throw together the two lots (rows 7 and 8, Table X.), the correlation would, of course, be decidedly negative. A second lot of 57 specimens aged 18 to 28 minutes was taken from the same culture about two weeks later. If we throw the two 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 435 lots together (Table XXXIV.) we have 106 specimens at this age (row 15, Table X.); the mean length is 143.82 microns, the mean breadth 50.832 microns, while the mean ratio of length to breadth is 35-438 per cent. The polygon for variation in length at this age is shown at c, Diagram 4, p. 440. (f) Age 35 to 45 Minutes (Table XX XV.).—From the same lot 6 (Table X.) from which came the first sets aged 0 to 19 and 18 to 28 minutes, there were taken on the same day 25 specimens that were allowed to reach the age of 35 to 45 minutes (row 9, Table X.). Growth has now become much slower. These specimens average 17 minutes older than the last set, yet they have increased in length only about 6.5 microns. The breadth remains about the same; the slight increase shown in the figures is probably not significant, since it disappears at the next stage. The mean ratio of breadth to length continues to decrease, reaching now 37.296 per cent. The correla- tion between length and breadth is more strongly positive than before (.2799), indicating that these dimensions are not changing so decid- edly in opposite ways. The polygon for variation in length at this age is shown at d, Diagram 4. (9) Age 75 to 90 Minutes (Table XX XVI.).—Forty-two speci- mens of this age were measured, taken on the same day from the same lot from which came the sets last described (lot 6, Table X.). The specimens average about twice the age of those in the last set, the absolute increase being 45 minutes, yet the growth in length has been only about 12 microns, which is about the same as the growth in the first five minutes after separation. The breadth still remains about the same; it is notably less than in the very earliest stages. The ratio of breadth to length continues to decrease, reaching now 33-558 per cent. Meanwhile the correlation between length and breadth has increased greatly, till now, at .5232, it is not much below that of the culture as a whole (.6469). (h) Age o to 90 Minutes.—From a single culture of D, on a single day, we have thus measured 140 young specimens, varying in age from 0 to 90 minutes. The constants for variability and corre- lation of such a collection are of interest; they are therefore given 436 JENNINGS—HEREDITY IN PROTOZOA. [April 24, in Table X., row 11. The variability, as measured by its coefficient, is less in both length and breadth than in the random sample, or in the collection of young specimens including only those under nineteen minutes in age. There is practically no correlation in the collection taken as a whole between length and breadth. This is because breadth at first decreases while length increases (giving negative correlation) ; later they increase together (giving positive correla- tion) ; the two tendencies about cancel each other in the collection as a whole. , Third Stage: Three to Five Hours Old (Tables XX XVII. and XXXVITII.). Three days later than the sets shown in lot 6, Table X., and under as nearly the same conditions as possible, I took from the same culture of progeny of D two sets of young, keeping the first set till the age was between 3 and 4 hours, the second set till the age was between 4.20 and 5 hours (see lot 9, Table X.). The culture was, however, in a different condition from that of lot 6; it contained a very large number of young and dividing specimens. A random sample of this culture, containing 195 specimens, is shown in Table VII. (page 412), while the constants for this sample are shown in row 19, Table X. The entire left portion of Table VII., up to the length of about 160 microns, or more, evidently consists of young individuals in various stages of growth. This decreases the main length (176.124 microns) and the correlation (.3945), while it greatly increases the variability in length (13.262, as against 6.821 for the random sample of the previous lot). (1) Age 3 to 4 Hours (Table XXXVII.).—The effects of dif- ferent environmental conditions are at once seen on comparing this set of 93 specimens (Table X., row 16) with the set 75 to 90 minutes old, from the previous culture (Table X., row 10). The specimens of the present lot, though 12 to 2? hours older than the others, are shorter, the length (149.636 microns) being less by about 16 microns. The breadth is about the same as in the previous set; the correlation between the two is rather low (.3201). (7) Age 4.20 to 5 Hours (Table XXXVIII.).—Ninety-five specimens kept for about an hour longer than those in the foregoing 1908.] JENNINGS—HEREDITY IN PROTOZOA. 437 set showed a rapid growth in length and breadth. The length now reaches 186.736 microns, the breadth 60.168; both dimensions are considerably greater than the mean of the random sample. Thus, the animals at this age had reached about the average size of the infusoria in a collection of the same descent taken at random. Table VI. (page 412) shows a sample of this same culture taken twenty- four hours earlier, at a time when little division was occurring; the mean length is very nearly the same as that of the young of the present set. The correlation between length and breadth has con- siderably increased. Certain peculiar facts are brought out by considering these two sets together (Table X., row 18). Here we have a collection of 188 young individuals taken at practically the same time from a small watch-glass culture. The variability and correlation depend in a - high degree on the length of time we keep these. If they are all kept three to four hours (row 16) or 4.20 to 5 hours (row 17), the variability in length is about 5 to 6, in breadth about 9. But when we keep part of them for the shorter period, part for the longer, the variability rises to about 12.5 for length and 12 for breadth. Again, the correlation between length and breadth is but .3201 and .5557 in the two lots taken separately, but when we take them together the correlation is much greater, rising to .7132. These relations show the important part which may be played by growth in determining observed variability and correlation; their significance will be taken up again in our general sections on these topics. Fourth Stage: 12 to 18 Hours Old (Table X., Lot 10). From the same culture of the progeny of D from which came the lots last described, but three days later were taken two lots of young, of 73 and 105 specimens, respectively, which were kept, the former to the age of 12 hours, the latter to the age of 18 hours. (k) Age 12 Hours (Table XXXIX., and rows 20 and 21, Table X.).—There is a still further increase in both length and breadth, as compared with the specimens 4.20 to 5 hours old (see Table X., rows 20 and 21). Among the 73 specimens of this lot were two of about the same size which were much smaller than the others (see Table XXXIX.). There is little doubt, I believe, that these are the prod- 438 JENNINGS—HEREDITY IN PROTOZOA. [April 24, ucts of a second division; either one of the twelve-hour specimens had divided, or there was accidentally taken with them an older specimen which divided. In either case these two specimens do not ‘belong in the twelve-hour lot, as they are much younger. On this account I have calculated the constants for this twelve-hour lot twice, once including these two small specimens (row 20, Table X.), the second time excluding them (row 21). The variability in length is much reduced—from 6.672 to 4.930—by the omission of these two. At the same time the correlation between length and breadth is like- wise reduced from .4868 to .3474. (1) Age 18 Hours (Table XL., and row 22, Table X.).—Growth ‘in length continues, though very slowly; in six hours the increase has been less than during the first five minutes after separation. The - animals at this age are decidedly longer than the mean for the cul- ture as a whole, as judged from the random sample of Table VII. (page —), taken three days earlier. The mean breadth of the eighteen-hour specimens, while greater than that of the random sample, has decreased as compared with that of those only twelve hours old. The variability of these two lots (12 and 18 hours old) of adult size is less than that of the random samples (for examples, rows 3, 6, 12, 19, Table X.). Fifth Stage: 24 Hours Old (Table XLI., and row 23, Table X.). A final lot of 300 specimens was selected while dividing and these were kept till they were 24 hours old. These were progeny of D, but were taken from the culture somewhat more than a month later than those o to 18 hours old. To understand their measure- ments it is necessary to take into consideration the cultural condi- tions. These animals were living in an ordinary hay culture, which was getting old, so that they were not dividing rapidly; they were rather slender in form. Now a large number of these was placed in a fresh decoction of hay and left there for 24 hours. They increased in size and began to divide rapidly. Now 450 dividing specimens (producing, of course, 300 young) were taken out and returned to the original culture fluid. This was for the purpose of - preventing a second division before the end of the period of twenty- 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 439 four hours. As a result of this treatment they did not grow so rapidly as did the twelve- and eighteen-hour lots, and are smaller than these. The purpose in studying this group (as well as other groups) was mainly to determine the variability and the correlation between length and breadth. Both are less, as Table X. shows, than is usually the case in random samples. The specimens 12, 18 and 24 hours old may be taken as types of adult Paramecia of this strain (progeny of D; caudatum form) before the changes leading to fission have begun. Diagram 4 gives polygons of variation for the different ages, in descendants of D, as compared with a random sample; it shows clearly the part played in the observed variations by the presence of different stages of growth. Sixth Stage: Preparing for Fission. As Table X. shows, the adults of the progeny of D (caudatum form) reach a mean length of 168.532 to 199.048 microns (rows 23 and 22) under the cultural conditions employed, while the mean breadth varies from 40.320 (row 23) to 62.796 microns (row 20). But the maximum length is (under the same conditions), of course, much greater than the mean. In the random samples we find indi- viduals up to 224 microns in length and 88 in breadth (see, for example, Table LI.) ; and among those 18 hours old (Table XL.) we find a length of 228 microns. Now, when we compare these large adults with the specimens actually beginning fission (which are supposedly the oldest of all), certain peculiar facts appear. The specimens beginning fission are by no means the longest of the lot; a given culture contains many specimens much longer than those showing the first signs of division. Thus, in the “ Lot 1” of Table VIII., we find 131 specimens in the very earliest stages of fission (Table XIII., page 442). The mean length of these is 175.696 microns (row 25, Table X.), and the longest specimen is 204 microns long. But in the random sample of the specimens that are not dividing, from this same lot (taken at the same time) the mean length is 199.960 microns (row 27, Table X.), and certain individuals reach a length of 240 microns (Table XIV., page 443). Of the two hundred specimens of the random aN nr > ° Percentage of the Whole. & LoS) [o) wn Nv un 15 Io 440 JENNINGS—HEREDITY IN PROTOZOA. [April 24, sample, 69, or more than one third, are longer than the longest of the specimens beginning fission. Only nine of the entire 200 falls belew the mean length of the specimens beginning division. ay | te | A \ ie y- \ tL | AA ea oe }/ WEF 8 eon X wee / SA —_ 10 116... 128 §=140, 152) . 164. 1976) 188 1200. pene eee Length in Microns. Dracram 4. Polygons of variation in length for descendants’ of indi- vidual D, at various ages. A (heavy line), Random sample, 195 specimens (row 19, Table X.). a, youngest halves, constriction beginning (row 1, Table X.). b, age 0 to 5 minutes (row 5, Table X.). c, age 18 to 28 minutes "(row 8, Table X.). d, age 35 to 45 minutes (row 9, Table X.). e, age 75 to 90 mihutes (row 10, Table X.). f, age 4.20 to 5 hours (row 17, Table X.). g, age 12 hours (row 21, Table X.). A, age 18 hours (row 22, Table X.). “1908. ] JENNINGS—HEREDITY IN PROTOZOA. 441 Since then the specimens beginning fission are not the longest of the culture, it is clear that the length decreases before fission begins. This is borne out by the form of the specimens beginning fission; though their mean length is less than that of the random sample, their mean breadth is greater (mean breadth 50.220 microns in the random sample, 55.480 in those beginning fission). While then the TABLE XI. Correlation Table for Depth of Constriction and Total Length in 313 Dividing Specimens from a Single Culture of Descendants of D. All taken the same day. Total Length of Body, in Microns. 5 156 160 164 168 172 176 180 184 188 192 196 200 204 208 212 216 220 224 = moore t 8 12 37 2218 31 18 -§ 6 4 FT. 1 131 erie © 2 7 (828) 7''5 2 37 12 ok tO vaea a's I I 30 = 16 RAS A a BSR A 29 .2.20 ahs y Panaie gee: WOMEN When TAM 12 & 24 I Zi hi Bae I 16 5 28 I ROAR ide Mk Yay aia cli ae A OMY 22 gs 32 I Wie ene ADP aa RMS SUR: 17 5 36 2 re Ma roe I | Io uw 40 2 1 Da 7A WB B=: © 44 I I s te z orao <7 2044.38 47 30 20°22 16°10 10 6 3 .6-'2.\2 [313 Length—Mean, 181.725 + .512H Depth of Constriction—Mean, 13.265" St. Dev., 13.446 + .362u St. Dev., 2.72TH Coef. Var., 7.399 + .201 Coef. of Cor. between Depth of Constriction and Length, .6882 + .0201 ; Increase in Length for 1 unit of depth, 860“; Coef. of Cor. if first row is omitted, .7818 + .o194. length decreases preparatory to fission, the breadth increases at the same time. How _ long before fission this change of dimensions begins I can see no way of determining. The period may perhaps be one or two hours. Thus, the longest individuals of the culture are the adults that have not begun the changes preparatory to fission. These decrease in length and increase in breadth before fission. PROC. AMER. PHIL. SOC. XLVII. I90 CC, PRINTED JANUARY 9, I900. 442 JENNINGS—HEREDITY IN PROTOZOA. fpr ag, TABLE XII. Correlation Table for Depth of Constriction and Breadth of Body, in 313 Di- viding Specimens from a Single Culture of Descendants of D. (Same lot shown in Tables XI., XIII. and LXII.) Breadth in Microns. rr S 40 44 48 52 56 60 64 68 72 5) 3 4 2619 OF BO Ba aT ue go tees pr B99) FB er Se 37 = 12 Mo i SES I ° Bats ae I 30° Wes hie an Ss fee aes Te 29 oy) POOR ee | 12 2 24 AOR rk 16 po 28 Aida ee ae: 22 SW Al Wer Secs me ae een 17 C136 2 veg @ 10 ian ae OW Sea emi 8 o 44 I I S Bie 2200! "FS Gs aS ure ee rere Q Breadth—Mean, 52.026 + .2094 Depth of Constriction—Mean, 13.2654 St. Dev., 5.473 = .148u St. Dev., 2.721¢ Coef. Var., 10.544 + .287 Coef. of Cor. between Depth of Constriction and Breadth, — .5232 + .0277; Decrease in Breadth with Increase of 10“ in Depth, 2.630». Omitting uppermost row: Coef. of Cor., —.3316 + .04454; Decrease in Breadth with Increase of 10H in Depth, 1.252. Taste XIII. Correlation Table for Length and Breadth of 131 Specimens of Lot r in the Earliest Stages of Fission. (Descendants of D, Table X., row 25.) Length in Microns. 156 160 164 168 172 176 180 184 188 192 196 200 204 5 44 I I 2 SUD. ro MA Wearatane Pana Spege 0h a Lr I 19 3 52 ToD NS Gy tan Oy Ree ae 27 56 3 Se BO Fone tae cine ea 47 -& 60 PAM ea Sicha aA INS WIND a ee 22 = 64 I aa, ae Da II 3 68 I I 2 o 72 I I i Y-8 12 17:22) 383k (8) 5 yee a Length—Mean, 175.696 + .556u Breadth—Mean, 55.480 + .207¢ St. Dev., 9.432 + .303« St. Dev., 5.040 + .210H Coef. Var., 5.368 + .224, Coef. Var., 9.082 + .382 Mean Index, 31.568 per cent.; Coef. Cor., .6546 + .0337. 1908.] JENNINGS—HEREDITY IN PROTOZOA, 443 Seventh Stage: Fission. Some of the data bearing on the dimensions during fission have been incidentally taken up in the account of the young in the earliest stages, before the two halves have separated. (m) Beginning Fission. Descendants of D (caudatum Form). —Four lots of dividing specimens descended from the individual D were studied. These lots were taken at different times; the first included 313 dividing specimens (Tables XI. and XII., and rows 25-29, Table X.) ; the second 62 (Tables XLII., XLIII. (appendix) and rows 30-32, Table X.); the third 77 (Table XLIV., and rows 23-24, Table X.) ; the fourth 37. The dimensions of random sam- ples of the same lots are given in Table X. The large lot containing 313 dividing specimens may be described as typical; the others show the same relations, except as hereafter noted. TABLE XIV. Correlation Table for Random Sample of Specimens not Dividing, of Lot It (from which came the dividing specimens of Table XIII.). (See Table X., row 27.) Length in Microns. SEBSSSRRESABZBABISSERLRLIRSAZSY He + SH HH HH YH HH HHP RP RP RP NN NHN ANNKnNnanaaneanaan 3 36 | 1 I 2 4 5 4o I I 2 ra the ania: BP eae | 12 o44/1 2 T3315 4010 G4: Qo Bea 44 Ss 48 I ie Saar ae Sy ee tae Ser Se te OR I 38 os: 52 2°2°2.5:66 773) 4: 4.1 47 aati GO 2 QL LE 2 2 sy i Ean y 33 S 60 I Pu tae er at 14 = 64 I 121 1| 6 2 68 fe) FQ 72 I I vs 21201 30 3 6 1116221928171811 1513 7 3 0 O 2/200 Length—Mean, 199.960 = .740" Breadth—Mean, 50.220 + .308" St. Dev., 15.528 = .524u St. Dev., 6.468 = .2184 Coef. Var., 7.765 + .263 Coef. Var., 12.877 = .441 Mean Index, 25.114 per cent.; Coef. Cor., .6064 + .0302. In the dividing specimens the length of the body increases as the depth of the constriction between the two halves becomes greater ; this is well shown in Fig. 2, page 416. In order to include only the earliest stages of fission we shall, of course, have to take the speci- 444 JENNINGS—HEREDITY IN PROTOZOA. [April 24, mens in which constriction is beginning. Among the 313 dividing specimens of lot 1 (Table XI.) there were 131 in which the depth of the constriction below the body surface was less than one unit of the micrometer scale (less than 4 microns). These may be taken as representing the earliest stages of fission. The depth of the con- striction is in these specimens less than one twelfth the breadth. Their measurements are given in Table XIII., while the constants deduced from the measurements are shown in row 25, Table X. These should be compared with the measurements and constants for the random sample of the specimens not dividing in this same culture (Table XIV., and row 27, Table X.). Examination of these tables shows the following remarkable facts: 1. The mean length of the specimens beginning fission (175.696 microns) is much Jess than the mean length of the random sample (199.960 microns )—although the latter must contain many specimens that have not reached adult size. 2. The range of variation in length is much less in the specimens beginning fission than in the culture as a whole. In those beginning division the range is from 156 to 204 microns; in the random sample it is from 148 to 240 microns. 3. The longest specimens beginning fission are 36 microns shorter than the longest of the random sample. In the random sample, 34.5 per cent. of all the specimens are longer than the longest of those beginning fission, while 95.5 per cent. are longer than the mean length of the specimens beginning fission. 4. The variation in length is decidedly less in the specimens beginning fission than in the random sample. In the lot beginning fission the coefficient of variation is but 5.368, while in the random sample it is 7.636. It may here be noticed that coefficient of variation in the speci- mens beginning fission is less than that for conjugating specimens. as studied by Pearl (1907). To this matter we shall return later. 5. In the specimens beginning fission the mean breadth (55.480 microns) is greater than the mean breadth of the random sample (50.220 microns). 6. The variation in breadth is much less in the specimens begin- 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 445 ning fission than in the others. In the former the coefficient is but 9.082, while in the latter it is 12.877. 7. The mean index, or ratio of breadth to length, is much greater in the specimens beginning fission; in these it is 31. 568 per cent., as contrasted with 25.114 per cent. in the random sample. 8. The correlation between length and breadth is high in the specimens beginning fission; it is somewhat greater than in the random sample. In the former it is .6546; in the latter .6064. Owing to the smaller numbers in the other lots of dividing speci- mens, I included in the group “ beginning fission ” all those in which the depth of the constriction below the body surface was less than one fourth the breadth of the animal. Thus, all specimens with constriction 12 microns deep, or less, were included. Of course, these groups contained specimens in decidedly more advanced stages of fission than in the large group we have been considering. The _- numbers of specimens in early stages of fission thus secured were respectively 40 (Table XLIII.) and 42 (Table XLIV.). The con- stants for these, in comparison with random samples or adults, are shown in Table X. (rows 24 and 30). As the tables show, these manifest in most particulars the same relations which we have brought out above for the larger and more precise set containing 131 specimens. The differences between the dividing specimens and the other individuals (as shown by the random samples, etc.) are in the main somewhat less in amount than in our first example. This is because in the smaller lots specimens are included in which lengthening and narrowing had begun, causing the dimensions to approach those of the specimens not dividing. The most striking difference between our large lot (Table X., row 25) and the smaller ones (Table X., rows 24 and 30) is in the correlation between length and breadth. While in the larger lot the correlation was high, in the smaller ones it is small or quite lacking. This is again due to the inclusion of more advanced stages in the smaller lots ; as the length increases the breadth decreases, tending to destroy the correlation. Descendants of ¢ (aurelia Form).—Two lots of dividing speci- mens were examined from the descendants of the small individual c. The first contained 119 specimens (Table XLV.) ; the second 63 446 JENNINGS—HEREDITY IN PROTOZOA. [April 24, specimens (Table XLVI.).> Selecting from these, as representing the early stages of fission, all those in which the depth of constriction is less than one fourth the diameter of the body, we obtain from the larger lot 66 specimens (Table XLVII.); from the smaller lot 38 specimens (Table XLVIII.). The constants for these, in compari- son with those for random samples, are given in Table X. (lots 4 and 5, rows 33 to 38). The measurements of the random samples are shown in Tables XLIX. and L. These specimens of the aurelia form show the same relations that are found in the caudatum form, with one exception. In lot 5 (Table X., row 36) the mean breadth of the specimens beginning fission is Jess than that of the random sample, instead of greater as in all other cases. But this peculiarity is due to environmental con- ditions. In lot 5 the breadth was very great in proportion to the length, as is shown by the dimensions of the random sample (Table L., and row 37, Table X.). In this lot the breadth was 41.555 per cent. of the length, while in most cases it is near to 30 per cent. This was due to the recent transference of the animals to a nutritive solution; they became very plump. Evidently, when preparing to divide the body tends to return to a constant form; in this case, therefore, it becomes narrower instead of broader. In the specimens of the aurelia form, as in the caudatum form, all dimensions are less variable in the specimens beginning fission. This difference in variability, as compared with the random samples, is very great in some cases. Thus, while the coefficients of variation in length for the random samples of lots 4 and 5 are 15.279 and 10.643, for those of the same lots beginning fission they are but 7.541 and 6.862, respectively. Had we included in the lots beginning fission only specimens in which the depth of constriction was still less, the coefficients of variation would have been still smaller. The constants for all specimens of c that are beginning fission, taken together, are shown in row 38, Table X. The standard devia- tions and coefficients of variation are, of course, greater than for 5In making these measurements of descendants of c, a higher power of the microscope was used, so that the single unit of measurement was 3% microns. This caused‘the tables (in the appendix) to take a somewhat differ- ent appearance from those of the descendants of D. 1908, | JENNINGS—HEREDITY IN PROTOZOA. 447 each of the two component lots taken separately, since the two lots differed as a result of different environmental conditions. (n) Later Stages of Fission—As the constriction deepens the animal as a whole becomes more elongated, while the breadth de- creases slightly. These relations are shown both for the descendants of D (caudatum form) and the descendants of c (aurelia form) in Table X. (rows 25 and 26; 30 and 31; 33 and 34). In the large lot 1 of dividing descendants of D, comprising 313 specimens (Table XI.) the correlation between length of body and depth of constric- tion below the surface is .6882. The length increases 8.6 microns with every increase of 10 microns in the depth of constriction. The correlation between breadth and depth of constriction (Table XII.) is — .5232, the breadth decreasing 2.63 microns for each Io microns increase in depth of constriction. If we include only the specimens in which lengthening has decidedly begun (thus omitting the earliest stages, in the uppermost rows of Tables XI. and XII.), then the correlation between length and depth of constriction is .7818; between breadth and depth of constriction, —.3316. With an increase of 10 microns in depth of constriction the length now increases 11.195 microns, while the breadth decreases 1.252 microns. In this same culture while the mean length of the 131 specimens beginning fission is 175.696 microns, that of the seven specimens having a connecting portion but 4 microns wide is 212.572 microns. Thus, the increase in length before separation takes place is 36.876 microns, or about 21 per cent. of the length at the time fission begins. The breadth has decreased from 55.480 microns at the beginning of fission to 43.428 microns in the seven specimens with the narrowest connec- tions—a decrease of about 21 per cent. The ratio of breadth to length decreases from 31.568 per cent. at the beginning of fission to 20.430 per cent. just before separation. Corresponding relations are shown in other lots of dividing speci- mens ; some of the data are given in Table X. 2. SUMMARY ON GROWTH IN PARAMECIUM WITH A GROWTH CURVE. We have thus followed the growth from the time when the indi- vidual is but half a constricting specimen to the period when it is again ready to separate into two new individuals. We are ready, 448 JENNINGS--HEREDITY IN PROTOZOA, [April 24, therefore, to outline the main features of the growth of Paramecium, and to construct curves which shall give an idea of the processes involved. In spite of an incredible amount of work devoted to col- lecting the data, certain of the less important features of the growth curves must remain obscure, but the main facts are clear. The main outlines of the changes due to growth are as follows: From the time the constriction appears in the mother until a few minutes after separation takes place, the length increases rapidly, while the breadth decreases a little. A few minutes after separation the processes become less rapid. The breadth soon reaches its mini- mum, then begins to increase like the length, though more slowly. Growth in length continues for at least eighteen hours; the time undoubtedly varies with the conditions. The breadth continues to increase for some time, but it undergoes marked fluctuations, due to environmental conditions. In lot 10 (Table X.) it decreased between the ages of 12 and 18 hours; this is probably an environmental effect, not one due to the normal growth processes. As the time for fission approaches the animals are considerably more than twice as long as the original halves from which they devel- oped. Now as fission comes on they shorten and thicken, all tending to approach a uniform length and thickness. There is thus much less variation in the dimensions at the beginning of fission than in specimens taken at random. Now the constriction appears and the animal begins to narrow and extend in the way already described, finally separating into two parts. If from our data we construct curves showing these changes, we get such results as are shown in Diagram 5. Method of Constructing the Curves.—The horizontal scale repre- sents the time in hours, while the vertical scale represents the meas- urements of the animals in microns. The upper curve shows the length, the lower one breadth, as measured from the base line. Fission is assumed to take place once in twenty-four hours, which is an approximation to a rate commonly occurring. The time between the appearance of the constriction and the actual separation of the tw halves is taken as one half hour. The relative distances of the two curves from the base line shows the relative dimensions of length and breadth. The vertical rise of 2 | ee JENNINGS—HEREDITY IN PROTOZOA 449 1908. ] - ‘eyep asisaid WOI pa}onsjsuod JOU a1 saAIND oY} JO sjIved uayoIq ayy, *‘pey}oous JOU SIR S2AIND ayy, ‘sinoy Fe 3e pue O je sind90 UOISsIy ‘soBe usaids oy} 1e SUOISUSUIP [enjoe oy} sautty ZOE st PAINS OY} O} SUIT aseq BY} WIZ ddULISIP aYT, “YISuS, [eurs1I0 9y} 0} YMOIS JO uoriodoid ay} sMOYs dAIND dy} JO POSIT [VIIA sy], “SAB JUDIIYIP oy} 3 YIpeoiq pue yyBua_ jo suorsodosd 24} SMOYS O dJUTT aseq 94} WOT, soAInd OM} OY} JO SIULISIP IATL[PI BY], “SUOIOIUT UT SiUaUOINSvOU ay} SdAIB oTROS [@o1j19A OY} Ssinoy Ul 9uIT} 94} sjUasomdos afeos [eUOZIIOY OY], “YIpeosq JOF yeyI (GJ) Sul] JOMO] oY} SYy}SuaT Fo aAINO dy} st TJ poysew our, soddn ayy, “ISP eased “AX IGRI, Worz ApoIIp poyold wmnigamvsvg Ul YIpeeiq pue YyBue, 10F ‘YIMOIS jO saAIng “S$ WvuoVICG ‘sInO}]T Ul assy OS, te. ee Set Or GE ers bi 168. Sa Fk. Or ee gi Os 6. ea ee oe es 68 or <0 ~ ~ ~ a 4 — Son pnd o $ & ~ ~ ‘Oo con) "SUOTNIT, Ul Y}pesIg pue yYISueT \N $ 7 | a goz 450 JENNINGS—HEREDITY IN PROTOZOA. [April 24, the curve of length shows the actual proportion of growth to the original length. The distance from the base to the curves is 357 times the actual dimension at the given time. In order to show changes due to growth alone all the data for such a curve should be measurements from a single uniform culture on a single day; otherwise environmental differences complicate the matter, as we shall see more clearly in the next division of this paper. Now, it is impracticable to obtain from a single culture on a single day measurements of all the required stages. We are compelled therefore to make certain corrections in some of the measurements, to compensate so far as we can for environmental differ- ences. As Table X. shows, the mean dimensions of random samples differ much in (for examples) lots 1 (row 3) and_6 (row 12). It will not do, therefore, to compare directly the young of these two lots. Since we have from lot 6 the greatest number of different stages, it is best to make the measurements from this the basis for the curve, correcting others, so far as possible, to compare with this. In lot 2 the mean length (Table X., row 6) is almost exactly the same as for lot 6, so that we may use the measurements of lot 2 without correction, so far as length is concerned. On this account we shall employ lot 2 for the earliest stages, in place of lot 1, though the latter is based on a larger number of specimens. Since the mean breadth of the sample of lot 6 is 64.880 microns, while that of lot 2 is but 46.020 microns, it is necessary to correct the breadth for lot 2. At first thought it would seem that the proper method of making this correction would be by multiplying the breadths of the different sets of _lot 2 by the ratio 64.880/46.020. This would be the proper method of pro- cedure if we were dealing with the same stages of growth in the two lots; the specimens of lot 2 would be made plump, like those of lot 6. But the stage with which we are dealing is that of the beginning of fission. Now, we have already seen that when the specimens not dividing are plump, the breadth does not increase at the approach of fission nearly so much as when the specimens not dividing are thin. Indeed, if the specimens are very plump, there is an actual decrease, instead of an increase, at the approach of fission. Our problem is: What would be the breadth of specimens be- ginning fission, in which the length is 82.600, and the animals are very plump, as in lot 6? This problem can best be solved by asking what is the ratio of breadth to length in specimens beginning fission, in a very plump culture? In lot 3 (row 7, Table VIII.) we have such a plump culture, and we find that the ratio of breadth to length is, in the earliest stage of fission, 78.563 per cent. We therefore take this as the ratio of breadth to length for the earliest stage of lot 2, from which the corrected breadth is found to be 64.893. If this decreases at the same relative rate as actually occurred in lot 2, then the breadth 15 minutes after the beginning of constriction would be 64.493 microns. We are compelled to use, further, lots 9 and 10 (Table X.). In lot 9 both length and breadth require correction to make them~-comparable with the measurements of lot 6. The correction is made by multiplying the 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 451 dimensions by the ratio between the length of the random samples of the two lots. In lot 9 we use only the average of the two sets, as given in row 18, Table X. : In lot 10, since we unfortunately have no random sample, we are unable to make a correction. Owing to the very great difference in the environmental conditions of lot 3 (rows 23 and 24, Table X.) we are unable to use the 24-hour-old specimens of that lot, although we need measurements at that age. The older portions of the curve (beyond 18 hours, at the right) cannot be plotted from exact data, and there are certain features of much importance for which it appears that the collection of such data would be almost impossible. As we have shown, before fission the animals shorten and thicken. How long before fission this begins it is not possible to say; in making the curve the period is arbitrarily taken as two hours. When we make the corrections above described, we have the following mean dimensions at different ages, as data for the construction of our curve. The ages given are the average ages for the lots considered; thus the age for row 8, Table X. (18 to 28 minutes) is taken as 23 minutes. TABLE XV. Dimensions in Microns of Paramecia (Descendants of D) at Different Ages, Corrected (so far as possible) to Correspond with Those of Lot 6, Table X. Data used in making the Curves of Growth. - Pte et ti Aa iieteee Tatiana: = Beginning constriction............ Row 4, Table VIII. 82.600 64.893 Fifteen minutes after beginning CONSHICHOR oc cs esosescesess. rigdaink tke key am df 85.774 64.493 2% minutes after separation...... “ 5, ‘ X. 107.660 59-355 SP PIATOS ce cceges vols uoussnss se dg Meee ele X. 128.000 60, 168 PMID UGS vec ns tidercressetetens se SER Vee ee X. 143.348 54.284 MD UIINOLGS ss vanspnaucasvecstoeks oc ses RA Qe X. 149.920 55.840 ASG MUMMIES 5 oo cos ince secede doses. cgi 5.0, Shaan a: 161.524 54.192 MUMOULS, 2.5550. ca ovnapeangeeroeds 3. dlls 2 Fe PEA X. 176.560 58.922 Mg AUOUUS 2. ss cteste sere pecans eecss aS ON uate X, 188.988 62.796 DRO sacih evan. sev sieeeeeiasesesiens Ry eee ie ae X. 199.048 56.499 Beginning constriction............ Se SOb ee X. 165.200 64.893 When we lay off on the vertical scale the distances corresponding to the lengths and breadths at the different periods, as given in the above table, and connect these points, we obtain the curves given in Diagram 5. Characteristics of the Curves——As the curves show, the length increases with great rapidity for about twenty minutes after fission ; continues less rapidly for about an hour, and still less rapidly for four or five hours. Now the increase continues, though very slowly, til! a maximum is reached at a length considerably greater than twice the original length; later the length decreases in preparation for 452 JENNINGS—HEREDITY IN PROTOZOA. [April 24, fission ; this decrease continues till the length is just twice the original length. Now the constriction appears, so that the animal may be looked on as two; the length, therefore, drops in a straight line to the original length found at the beginning of the curve. The breadth decreases from the beginning till about an hour after fission; then slowly increases; it shows in the course of the twenty-four hours many fluctuations which are doubtless mainly due to differences in the environment—especially to differences in the amount of food taken. In preparation for fission the breadth increases at the same time that the length decreases. The curve of length is much the more interesting of the two, since it isthe one which represents mainly the actual growth. It is of great interest to find that this curve of growth in a single cell is of essentially the same form and character as those which have been obtained for the growth of many higher organisms, composed of many cells. A number of such curves are brought together in the recent interesting paper of Robertson (1908). Inspection shows at once that the curve of growth in Parmecium closely resembles that for growth of the rat, as worked out by Donaldson (1906); for growth of man, and for growth in various other organisms. The curve of growth, as is well known, is a logarithmic curve in the cases where it has been worked out mathematically. While the growth in Paramecium has merely been plotted empirically, it is evident that it is essentially a similar logarithmic curve; this could doubtless be worked out from the data given. The fact that the curve of growth is essentially the same in the unicellular organism as in the animal composed of millions of cells is in some respects surprising. In the brain of the rat, or in its body, the curve of growth is the resultant of the growth of many different groups of cells, some groups growing at one period, some at another; yet the resultant curves are of the same character as when there is growth in but a single cell. The temporal relations shown in the curves are likewise of much interest. As our diagram shows, that portion of the curve showing the greatest curvature requires in Paramecium about four hours from the beginning. In the rat the corresponding part of the curve takes several months, while in man it requires several years. It 1908. | JENNINGS—HEREDITY IN PROTOZOA. 453 seems extraordinary that a process following the same laws should in some cases be measured by hours, in other cases by months, in others by years. 3. EFrEcTs OF GROWTH ON THE OBSERVED VARIATION. A random sample of an ordinary culture of Paramecium contains specimens falling in all parts of the growth curves represented in Diagram 5. If we measure the various members of such a sample, as was done by Pearl (1907), we shall then find many variations in size, which variations consist to a considerable extent of different growth stages. Not all the observed variations are due to this factor, but its importance is very considerable. This will best be appreciated by running through the columns headed “ coefficients of variation” in Table X. If we take samples including specimens falling in the early parts of the growth curve, when the absolute size is small but the changes with growth are very marked, then the coefficients of variation in length are high; thus in rows 4 and 5 they are 15.494 and 13.729, respectively, while in the random sample of the same culture the coefficient is but 8.834 (row 6). On the other hand, if we take specimens restricted to a very small portion of the curve, the coefficient of variation becomes very low; thus in a lot whose age falls between 18 and 28 minutes the variation is but 4.521 (row 8) ; at the age of 4.20 to 5 hours is 5.043 (row 17), though the variation for a random sample of this same culture is 13.262 (row 19). The effects of growth on variation are shown to the eye in Diagram 4, Pp. 440. Variation at Fission—The effects of growth on the observed variation are likewise seen when we compare random samples with individuals that are at a definite stage in the life history. Thus, if we take specimens at the beginning of fission, when the constriction first appears, we find the coefficient of variation very low, as com- pared with those of random samples of the same cultures. This is readily seen in the following tabulation of the coefficients of varia- tion for the four cultures of Table X. in which the specimens begin- ning fission were studied (see next page). Variation in Conjugants——Again, the same thing appears when we compare conjugating individuals with random samples of the 454. JENNINGS—HEREDITY IN PROTOZOA. [April 24, same cultures. Conjugation does not occur till a certain stage of growth has been reached, and the conjugants do not include speci- mens undergoing the changes preparatory to fission. The conjugants would then fall in those portions of the growth curve that are nearly straight; that is, there would be in these little variation due to growth. TABLE XVI. Coefficients of Variation. Length. Breadth. Lot. ree Random Sample. ig Random Sample. I 5.308 7.765 9.082 12,877 2 5.320 8.834 6.769 11,421 4 7.541 15.279 9.911 15.683 5 6.862 10.643 12,071 ' 13.720 Pearl (1907) has already shown that the observed variability of con- jugants is less than that of random samples of the same culture. I have made extensive studies of conjugants and find the same thing. Details regarding the relation of conjugation to variation and heredity are to be taken up in a later communication; here I give merely the coefficients of variation for certain cases, as compared with those of random samples. TABLE XVII. Coefficients of Variation for Conjugants, as compared with those for random samples of non-conjugants of the same culture. L | Length. Breadth. ot Conjugants. | Non-Conjugants. Conjugants. | Non-Conjugants. A, Pearl 6.668 8.185 9.398 II.112 Rae eh 7.439 9.123 7.910 10,894 a, Jennings, 7.39” 11.578 12.409 19.176 i “f 7.678 11.026 15.766 18.142 On comparing the coefficients of variation in conjugants, as given in Table XVII., with those for specimens beginning fission (Table XVI.), and those for specimens at definite ages (Table X.), it is found that in the conjugants the variation is not so small as it is in specimens at definite growth stages. This shows clearly that nothing is required to explain the low variation of conjugants, save the fact that a certain number of growth stages (the earlier and later ones) 1908, ] JENNINGS—HEREDITY IN PROTOZOA. 455 . are lacking in these. There is no evidence of an unusually low degree of congenital variation in the conjugants, for the non-conju- gating specimens beginning fission show a still lower variability (Table XVI.). It appears highly probable that if we could examine a large number of individuals, derived from the same parent, cultivated under identically the same conditions, and all in precisely the same stage of growth, we should find coefficients of variation considerably smaller than the smallest we have found, which is 4.521 (row 8, Table X.). Indeed, if we could further exclude all inaccuracies of measurement, it is quite possible that the coefficient of variation would approach closely to zero, if it did not reach it completely. This would, of course, mean that the variations observed among the progeny of a single individual are not congenital, but are all due to growth and environmental action. Further evidence of this will come out later in this paper. 4. EFFECTS OF GROWTH ON THE OBSERVED CORRELATION BETWEEN LENGTH AND BREADTH. As Diagram 5 shows, the curves of length and breadth diverge at the beginning, then run for a considerable distance nearly parallel, then finally approach each other. That is, at first the breadth decreases while the length increases; later they increase together; and still later the breadth increases while the length decreases. If a collec- tion of specimens includes individuals in various different stages of growth (as is usually the case), then these various relations of breadth to length will deeply affect the amount of correlation observed between the two dimensions. Thus, if we take a collection composed of various ages under one hour, when the length is increasing while the breadth is decreasing, then on the whole greater length will be associated with less breadth, so that the correlation between them will tend to be negative. This is the explanation of the negative correlation shown in Table X., rows 2, 4, 5, 7, I1, 13, 14. Next follows a period (from about the end of the first hour to the fourth) in which the inclusion of indi- viduals of different ages tends to cause a certain degree of positive correlation, since the two dimensions are increasing together. Then 456 JENNINGS—HEREDITY IN PROTOZOA. [April 24, comes a long period in which both dimensions remain nearly the same—the length increasing slowly, while the breadth fluctuates. Different growth stages during this period have little marked effect on the coefficient of correlation between length and breadth; they tend to prevent its reaching 1.000, but this it would not reach for other reasons. Now, for a certain period before fission (taken as.two hours, in our curves ), the length decreases while the breadth increases. Greater breadth will then be associated with less length, tending to produce again a negative correlation. If we make a collection of individuals representing various stages in this process, we should, therefore, expect to find the correlation much less than in collections taken (1) either before these processes have begun, or (2) after they are ended. We can realize this, in the main, by taking from a large random sample all the largest specimens (which are, of course, the older ones) and combining these into a single correlation table with specimens from the same culture that are beginning fission (the oldest specimens of the culture). I performed this operation for lot 1 of Table X. This collection contains 131 specimens beginning fission (row 25, Table X.), and 134 specimens (not dividing) that are 196 microns, or more, in length (row 28, Table X.) ; throwing these together, we have a collection of 264 of the oldest specimens in the culture (row 29, Table X.). For the 131 specimens beginning fission the coefficient of correlation is + .6546; for the 134 large specimens it is + .4681. When the two are taken together the corre- lation disappears. The computation gives us a coefficient of + .0350, but this is less than its probable error (.0415), so that the figures have no significance; no correlation appears. The effects of the inclusion of various growth stages on the observed correlation shows itself in many other ways, which will become evident to anyone who carefully examines the data of Table X., in connection with our curves of growth (Diagram 5), and the relations brought out in the foregoing paragraphs. Note, for exam- ple, the coefficients of correlation for lot 9 (rows 16-18, Table X.). For the specimens 3 to 4 hours old the coefficient is but .3201, and for those 4.20 to 5 hours old it is .5557. When we throw these two lots together, so as to include a much greater proportion of the 1908.] JENNINGS—HEREDITY IN PROTOZOA. 457 growth curve, the correlation rises to .7132. In this larger collection the short specimens are much the narrower, the large specimens much broader—giving high positive correlation. Slight changes in one dimension may not be accompanied by notable changes in the other, while great changes in one are always accompanied by changes in the other. This is a relation which we shall meet again. While thus growth has a very great effect on the correlation to be computed from the measurements of a collection of Paramecia, it is important to bear in mind the fact that it is by no means the only factor concerned in correlation. ‘This becomes evident as soon as we take a collection in which the specimens are all in nearly the same stage of growth; the coefficient of correlation is then high. This is perhaps best realized by considering specimens in the begin- ning of fission. As we have before noticed, in the collection of 131 specimens beginning fission, from lot I, great pains were taken to include only a single stage in the process. This collection gives a high positive correlation of .6546. This correlation can be due only to the fact that in specimens at a single growth stage the length and breadth tend to bear a certain proportion to each other. The effects of this are clearly seen in many other collections of Table X. Thus, in rows 8, 9 and 15 the specimens all fall in the period when length is increasing while breadth is decreasing; yet there is in each case a small positive correlation. This is due to the fact that the period of growth over which each collection extended was small, so that the negative correlation due to growth was more than counterbalanced by the inherent proportionality of length to breadth. A collection including only specimens that were all in the same stage of growth would undoubtedly (other things begin equal) show a high corre- lation between length and breadth, no matter what point on the growth curves they represented. This signifies, of course, that in any given stage of growth the relation of length to breadth tends to be the same in all specimens—although in different stages of growth this is often not the case. Other factors which modify the correla- tion will be considered in the later sections of this paper ; a summary of all these factors will be presented in a special section. With this we conclude our study of growth in Paramecium; PROC. AMER. PHIL. SOC, XLVII. I90 DD, PRINTED JANUARY IT, I909. 458 JENNINGS—HEREDITY IN PROTOZOA. [April 24, being prepared to understand the part played by this in the observed variations and correlations, we may pass to other factors affecting these. IV. THE EFFECTS OF ENVIRONMENTAL CONDITIONS ON DIMENSIONS, VARIATION AND CORRELATION. The data for the study of growth, just concluded, show inci- dentally that environmental conditions affect profoundly the dimen- sions, variation and correlation in Paramecium. As we have seen, samples taken from the same culture on two successive days are not strictly comparable for determining matters relating to growth, because of the environmental changes from day to day, inducing marked changes in the organisms. Thus, in a given culture we found that the mean length at the age of 14 to 12 hours was 161.524 microns ; three days later specimens more than twice as old, from the same culture, were smaller, measuring but 149.636 microns. We wish now to investigate the causes of such differences. We shall not attempt at present a systematic investigation of the effects of different chemical and physical agents on size, form and variation, though this is a matter which much needs study. Our present object is rather to examine the effects of altered nutritional conditions and of the commoner “ favorable” and “unfavorable” conditions. We shall study the variations from the standpoint of interest in the organism rather than in the agents inducing them, the purpose being to form a conception of the changes which may be looked for in Paramecium as a result of common alterations, mainly nutritional, in its cultural conditions. One of the results of this study will be to show that we cannot assign a definite effect to each agent taken in any absolute way. What effect a given agent will have depends on the previous condition of the organisms on which it acts. The same agent produces at one time an increase in size, at another a decrease; at one time it increases the variability; at another it decreases it. A given agent may either increase the positive corre- lation between length and breadth, or it may decrease it or convert it into a negative correlation. In succeeding days the same agent may produce these diverse effects on the same set of Paramecia. - U 1908.) | JENNINGS—HEREDITY IN PROTOZOA. 459 Yet, of course, these results are not produced haphazard; what we wish to study are the laws they follow. The effects of the environment were studied mainly on the same animals that served for the study of growth. Two strains were used; one consisted of descendants of the individual D, of the cau- datum form, the other of descendants of ¢ (aurelia form). The results show the extent of the variations producible through environ- mental action in the progeny of single individuals niultiplying by fission. No conjugation occurred in the D strain during the time it was under experimentation. On a given date, therefore, the age of the individuals, as measured in generations of the “ cycle,’ was about the same. Table XVIII. gives a summary of the statistical results in the experiments on the effects of the environment; it will be referred to frequently in the following account (see next page). 1. Proceny or D (caudatum Form). The individual D was isolated April 12, 1907; it measured, as nearly as could be determined when alive, about 250 microns. It was placed in culture fluid made of boiled hay and the progeny were kept in such cultures for months. Characteristic progeny of D are shown in Fig. 1, a to d. The experiments with the descendants of D may be divided into three series. First Series. Old Large Culture-——On June 11 a sample of 100 of the descend- ants of D was killed, from a hay culture that had stood several weeks and was flourishing, though multiplication was not occurring actively. This culture was in a vessel about nine inches across. The measure- ments of this sample are given in Table V. (page 406), while the constants are found in row 1, Table XVIII. Effects of Fresh Hay Infusion—Three days after these measure- ments were taken, a number of individuals of this culture were removed and placed in a fresh hay infusion, in a watch-glass; in this they were allowed to remain 24 hours. The increased food in the fresh infusion caused them to increase much in breadth (from 49.000 microns to 64.880 microns), and at the same time to begin to 460 TasLe XVIII. Effects of Environmental Conditions on Dimensions and Constants of Varia- same culture at the same time (except in rows 12, 15 and 20). The appendix or elsewhere, in which fuller data are given for the lot in JENNINGS—HEREDITY IN PROTOZOA. [Apis 24, 16 17 A. Progeny of D. First Series. Random sample of D, June 11, 1907 Same after 24 hours in fresh hay infusion, June I5.......... Two days after last; culture fluid not renewed, June 17... Same, after 24 hours in fresh hay infusion. Rapid multi- plication, June 18 Same, one week later; bac- teria multiplied injuriously, JUNE! 25). .0..< sb eacuaestbowepievens Starvation, same as row 2, but left 11 days in small quantity of fluid, June)25s).cccsecoresnsts ate emma meee were sane ee seeeee Second Series. 24 hours in fresh hay infusion ; rapid multiplication, Jaly 17.. Same as last, but starved a week, July. 245.5 .53 fesesesekaee’ Same as last, but 24 hours in fresh hay infusion, July 25... Same as last, but kept 1 week without change of fluid, July 3 Same as last, but kept 48 hours in fresh hay infusion, Aug. 3..! Rows 8, 10 and 11 combined... Third Series, Slender, old culture, in large jar,’ September 15;...,.55.0cscne Same as last, after 48 hours in fresh hay infusion, Septem- OHI Byes cy cecstsacieees dees seeee B. Progeny of c. Random sample of c, June 11, 190 Pee eee t eee eee e ees eeeeeseeseee Random sample of ¢, August 9..| Number of Individuals, 100 200 10o | tele) Table, 52 Length. Mean in Microns. Standard Deviation in Microns. Coefficient of Variation. Range of Variation in Microns. 188.360-+ .980 184.680+- .848 185.008+ .836 176,124-1,128) 201,888-+-1.147 149.360+ .736 I .100 .776 563 754 146,108 163.932 174.400+ .819 943 748 191,360 180.624-+ 202,280-+1,.031 175.320--1,060 188,800-+- .980 130,120+ .628 123.666+ .813 .692 .600 14.5324 12.596+ 14.420 .592 23.300 .797 22.680+ 811 10,896+ .520 16,264+ . 10,228+ , 20.9284, 14.876+ . 17,116+ 23.5374 15.2844 .729 15.708-++ .749 20,540-+ 1,092 9.284-- 12,040 443 573 7-715 -£.370 6.821 .327 7-:794.324 13.262+.461 11,233-4.407 7.296.350 8.834-+.300 7.003.274 12.767+.331 8.530+.335 , 8.945.351 13.795 +.316 7.556+.362 8.959+.431 10.879-+.371 7.134.342 9.736.469 128-228 156-224 148-212 104-220 140-256 128-188 140-216 120-176 120-220 132-212 136-240 120-240 160-232 124-216 124-232 104-156 100-160 JENNINGS—HEREDITY IN PROTOZOA. 461 1908. ] TABLE XVIII.—Continued. tion in Paramecium. Each row consists of specimens taken from the column headed “Table” gives the number of a table found in the question. Breadth. gee 2 , oi Meat PRT Ass he Coefficient of Mean in Standard Coefficient of Range of ae 38 5 Correlation, Be rte eT La tienes, | Se 49.000-+-.548 | 8.144-+.388| 16.6184 .814 28-76 26,029 | .4188-+.0556 64.880+.580 | 8.624+.412}| 13.292+ .645 44-88 35.131 | .6469-+.0392 43.556+.392 | 6.748+.276| 15.490+ .651 32-60 23.517 5955+.0375 47.364+.344 | 7.132+.244| 15.057-+ .526| 32-72 27.153 | .3945-.0408 56,112+.395 | 7.808+.279| 13.913 .507 36-80 27.850 | .6771-.0274 38.080+.356 | 5.288+.252| 13.881-+ .675 28-52 25.515 .4481-+,0539 46,020+.251 | §.256+.177| 11.421-+ .390 36-60 25.084 | .4282+.0389 31.180+.212 | 3.881.151 | 12.473+ .493 20-40 21.337 .3906-+.0467 46,684+.488 | 13.484+.344 | 28.879+ .793 20-80 28.236 | .8463-+.0102 44.800+-.429 | 7.796-+.304) 17.397 .698 32-68 25.657 | .5704+.0372 54.880+-.431 | 7.824+.305 | 14.255-+ .566 36-84 28.639 | .7364-+.0252 43.600+.377 | 11.852+.266| 27,184+ .654 20-84 49.600-+.298 | 4.412+.210| 8.896+ .428 40-60 24.593 .4085 -+.0562 63.160-+.472 | 7.000+.334/ 11,083-+ .535 44-80 36.123 | .5376-+.0480 56,380+.427 | 8.956-+.302| 15.884+ .549 40-80 30.350 |—.2613-+.0414 36,280+-.260 | 3.880+.184 | 10,700-+ .516 28-44 27.913 | .5208-+.0492 33.600+.400 | 5.917+.283 | 17.608+ .865| 23.3-50 27.136 | .6258-+.0410 462 JENNINGS—HEREDITY IN PROTOZOA. Taste XVIII.—Continued. [April 24, 20 Row. SH) Length B. Progeny of c. Bs 3 Continued. a2 5 Mean in Standard Coefficient of | Range of Za Microns, Re iam Variation, | Variation = n Microns, in Microns. Same as last, but 24 hours after addition of boiled grass, Au- Sst TO. canes ca veeeaeweeeeeen 225) 49 |114.163-+ .784/17.443-+ .555) 15.279-+.497 |73.3-160 Same as row 17, but 24 hours in fresh hay infusion, August 12 iG caaneeesasahees sneskeparmenoad 100} 50 |114,033-+ .820|/12,140+ .580| 10,646-+-.513 |86.7-146.7 Rows 17 and 19, together ; same animals, half in old fluid, half mn: Me@W s,s. ccsatecces peveganes 200} — |118,850+- .622/13.037-++ .440| 10,698-+-.374 |86.7-160 Conjugating culture, large ves- : l sel, September 25 ...:......... 200] 57 |158.800+ .877 18.384 .620) 11.578-++.396 | 124-200 Same culture, 5 days after, food petting ‘SCAYCE iss cap duesesan tae 100} 58 |129,640+ .867,12,848+ .613! 9.911.477 | 100-152 Large, old culture, January 23, TOOG3 1 (5.7. icneepapaheeee een 100} 59 |144.880-+1.097|16,264+ .776| 11,224+.542 | 100-176 Same, two days later, January BES TOS. .saviaaenoataee coneelen 50| — |130.640+1.227'12,863+ .868) 9.846+-.670 | 104-156 Another old culture, January 234) TOOS! is, Wai penheeren muenee 100] — |137.200+ .842,12.488-++- .596| 9,102-+-.438 | 104-162 Same as row 23, but starved 3 weeks, February I4............ 37| — |102.594-41.16110.467+ .821| 10,202+.808| 76-128 Same as row 23, but cultivated in small watch glass, January 30-February 15, 1908......... 109} 60 |100,320+ .52g° 7.828-+ .373| 7.804+.374| 76-120 multiply. The measurements of a sample of 100 of these are given in Table LI. (appendix), while the constants are found in row 2, Table XVIII. The increased breadth, with little change in the length, of course, results in an increase of the mean index or ratio of breadth to length; while in row 1 this was but 26.029 per cent., in the present lot it is 35.131 per cent. It is worthy of notice that with the increase in ratio of breadth to length there is an increase in the cor- relation between length and breadth from .4188 to .6469. Scarcity of Food.—The watch-glass culture just described (row 2, Table XVIII.) was now allowed to stand for three days (till June 17) without renewing the culture fluid. The animals had multiplied greatly, so that food became scarce; as a result they became thin. The measurements are given in Table VI. (page 412) and the con- stants in row 3, Table XVIII. While the length remained about the same, the mean thickness of the body decreased from 64.880 to 43.556 microns. The mean ratio of breadth to length fell from 35.131 per 463 1908.] JENNINGS—HEREDITY IN PROTOZOA. TABLE XVIII.—Continued. ue med Breadth, Bos oss A.2o8 8 ‘ mos bod Coefficient «f Mean in Standard Coefficient of Range of | Gm 33 5 Correlation, Microns, _ Deviation Variation, _ Variation Ss 5am in Microns, in Microns, 34.207+.241 | 5.363.171) 15.683-+- .511 20-50 30.177 | .6757+.0244 47 300.437 | 6.490+.310| 13.7204 .667| 36.7-66.7 | 41.455 .8152+,.0226 40.450+.441 | 9.247+.312| 22.8574 .810| 23.3-66.7 .1758-+.0462 38.560+.353 | 7.396.249) 19.176+ .670 16-60 24.244 7135 -+.0234 35.440+.400 | 5.928-+.283| 16.730-+ .820 20-48 27.262 | .7576-+.0287 54.160+.765 | 11.346+.541 | 20.948-+-1.042 32-84 37.106 | .8500-++.0187 37.760+.639 | 6.697-+.452| 17.736-+1.233 28-52 28.975 .4141+,0790, 37.960+.413 | 6,128-+-.292] 16.142+ .790 24-56 27.625 | .6691-+.0373 23.892+.644 | 5.804+.455| 24.291+2.014 16-40 23.067 | .8018+-.0396 26.480+.266 | 3.944+.188| 14.895+ .753 16-36 26.321 -7671-+.0278 cent. to 23.517 per cent., and at the same time correlation between the two fell from .6469 to .5955. Thus, within a week we find enormous fluctuations in breadth, due to changes in the amount of food, while the length remains about the same. The breadth is much more affected by nutritional changes than is the length. Rapid Multiplication.—To the watch-glass culture just described (row 3) new hay infusion was added. Twenty-four hours later (June 18) multiplication was occurring actively; stages of fission and all the stages of growth were numerous. Measurements of 195 specimens; taken at random at this time (Table VII., page 412, and row 4, Table XVIII.) show a very great increase in the range and amount of the variability in length, while there is little change in the breadth. This is, of course, due to the fact that the culture contains many young; these differ much from the adults in length, but little in breadth. The mean length decreases from 185.008 to 176.124 464 JENNINGS—HEREDITY IN PROTOZOA. [April 24, microns, and the variability in length almost doubles, increasing from 7.794 to 13.262. Owing to the inclusion of many young individuals, in which the length is increasing while the breadth is stationary or decreasing, the correlation between length and breadth decreases to 3945. Inspection of Tables VI. and VII. (page 412) shows at a glance the great effect of nutrition and division on the range and distribution of variations in size and form. Injurious Bacteria——A remarkable effect of what may be called “bad” conditions is shown in this series of experiments. The same watch-glass culture shown in row 3, Table XVIII., was allowed to stand for a week, till June 25. Bacteria of a certain character mul- tiplied greatly, and seemed to get the upper hand of the Paramecia. The latter became opaque and abnormal in appearance, and some of them died, disintegrating into shapeless masses. It was now observed that many of the specimens still living were very large, and that variation in size was extreme. The distribution of the variations is shown in, Table LII.; the constants in row 5, Table XVIII. Though no multiplication is occurring, so that no young are present, the range of variation is from 140 to 256 microns, while in row 3, from which this lot is derived, the range is only from 148 to 212 microns. The mean length has increased to 201.888 microns, one of the greatest mean lengths ever observed in progeny of D. The maximum size for descendants of D was likewise reached in this culture; in no other case were specimens 256 microns long observed. Starvation.—In striking contrast with the effects of much nutri- tion (row 4, Table XVIII.) and of injurious bacteria (row 5) are the results of starvation (Table LIII., and row 6, Table XVIIL.). The starving culture consisted of individuals from the same culture as row I, placed in fresh hay infusion June 14. The constants before they were placed in the hay infusion are given in row 1, Table - XVIII., while the immediate effects of the infusion are shown in row 2 of the same table. The same animals were left in this fluid for eleven days, till June 25. They had evidently begun to starve; they were small and thin and almost half of them had died. The dimensions are given in Table LIII., and the constants in row 6, Table XVIII. The length had fallen from 184.680 to 149.360 microns; the breadth from 64.880 to 38.080 microns. The breadth 1908.] JENNINGS—HEREDITY IN PROTOZOA. 465 decreases with lack of food proportionately more than does the length, so that the ratio of length to breadth has fallen from 35.131 per cent. to 25.515 per cent. It is to be noticed, however, that this greater proportionate decrease of breadth takes place in the first days after the withdrawal of abundant food, since after the animals had been only three days without new food the ratio of breadth to length fell to 23.517 per cent. (row 3, Table XVIII.) ; it did not decrease farther after starvation began. A comparative inspection of Tables VII. (page 412) and LIII. (appendix) shows to the eye the very great effects of nutrition on size and variation. Second Series. After the series of experiments described above, the progeny of D were kept in large culture jars of hay and water for about three weeks. Then followed an exceedingly instructive series of experi- ments on the effects of environmental conditions, the results of which are shown in Tables XIX.—XXII. and in the large Table XVIII, rows 7 to 12. Mere inspection of the correlation tables shows the effects in such a striking way that I have placed the main tables - together in the text, instead of relegating them to the appendix. Fresh Hay Infusion—On July 16, 1907, specimens from the large cultures were placed in a watch-glass of hay infusion and allowed to remain twenty-four hours. This induced rapid multipli- cation; while this was occurring a random sample of 200 specimens was measured, with the results shown in Table XXX. (appendix), and in row 7, Table XVIII. Starvation.—Next these were allowed to starve for a week; then I50 specimens were measured (Table XIX., and row 8, Table XVIII.). The results may be compared with our other starving culture of Table LIII., and row 6, Table XVIII. It will be noticed that for both length and breadth the amount of variation is not great ; that the absolute dimensions are small; that the ratio of breadth to length (21.337 per cent.) is the least we have even seen, and that the correlation between length and breadth is very low (.3906). Effects of Abundant Food on a Starving Culture—Now this starving culture (Table XIX.) was placed for twenty-four hours in ¢ 466 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TaBLe XIX. Correlation Table for Length and Breadth of a Starving Culture of De- scendants of D. (Row 8, Table XVIII.) Length in Microns. 4 S§FESSPFSESBSSSES ° g 20 I I S 24\/1 11 12.2 ae | Io ~ 22/1 6 2 5 12103 9 4 2 54 +32 I 43818119 2 I 48 S 36 2.3 3°97 12 8/ Res 8 1 | 30 S 40 I 3 cig GUN a al 2 2 8 6 11261621 2223 6 4 I I I|I50 Length—Mean, 146.108 + .563u Breadth—Mean, 31.180 + .2126 St. Dev., 10.228 + .398u St. Dev., 3.881 + .151u Coef. Var., 7.003 + .274 Coef. Var., 12.473 + .403 Mean Index or Ratio of Breadth to Length, 21.337 per cent.; Coef. Cor., 3906 = .0467. TABLE XX. Correlation Table for Length and Breadth of Descendants of D when a Starving Culture (Table XIX.) is placed for 24 Hours in Fresh Hay Infusion. (Row 9, Table XVIII.) Length in Microns. STASSSTSSSSTSLR STS sag ggeeg 20 I I 2 71 el Whe HN MR sates When tee. Nn Mh 18 fa eh Ue Se Sa Be Se ae) OG eh i Te 34 B52 tT (OV\GHOeae ue I 27 S 36 r1 3 5.8 4 eee 22 2 40 1 2) gNg a eae aoe 27 = 44 I 12.1) 4-2 86 ous I 27 < 48 I 2.5 2 §os, Oa econ’ eee 38 Tae ARS ee ae Wi Gly da aes Ba Ww a Se) 38 = 56 2: PERS ee a Oot 39 ™ 60 eis ee: OR bn a Me he aA a 32 & 64 11:85:39 4.24 I| 24 mA 68 tr $12.6 35am 13 72 rae Lise I 5 76 I I 3 80 I I 4 3 6 7 21222018 21 22 25 291514 2125191219109 I 3 2 1 I/\30° Length—Mean, 163.932 + .754u Breadth—Mean, 46.684 + .488u St. Dev., — 20.928 + .533u St. Dev., 13.484 + .344u Coef. Var., 12.767 + .331 Coef. Var., 28.879+ .793 Mean Index, 28.236 per cent.; Coef. Cor., .8463 + .o102. Breadth in Microns. 1908, ] JENNINGS—HEREDITY IN PROTOZOA. 467 , k TasLe XXI. Correlation Table for Length and Breadth of Descendants of D, after Re- maining One Week in Hay Infusion, Unchanged. (Row 10, Table XVIII.) Length in Microns. SESFSSESsSLLSzsaggges wv 32 t (33 2 it 9 5 36 | 1 2 ae a ea ge y 22 5 40 Tey Sak dee ae bee ae ce ee ae a | rey. 31 S 44 ROE cafes Meer oes Oe MM Fae ae 27 ¢ 48 I + ia aU i, Mh Ge 23 om Eg I I 2 VE ie eee SPR WL) be oR I| 20 = 56 I ts 2 5 a I 9 = 60 et ae I 6 % 64 ° 68 I po 8 3 Proce oO 2 OS. itr TF 16 33.2015 10.8. 6 °F) Be ee Length—Mean, 174.400 + .819" Breadth—Mean, 44.800 + .429" St. Dev., 14.876 = .579u St. Dev., 7.796 = .304u Coef. Var., 8.530 + .335 .5704 + .0372. Coef. Var., 17.307 + .608 Mean Index or Ratio of Breadth to Length, 25.657 per cent.; Coef. Cor., Taste XXII. Correlation Table for Length and Breadth, after the Culture shown in Table XXI. has remained 48 hours in Fresh Hay Infusion. (Row 11, Table XVIII.) Length in Microns. S2FESBSFSRESASSRGTELLLTTSSE I 2 I ae t2/:3 Piroweege ot I ee SS BA ee oe I I 03, RFS (Bi, Be ok re 2 I Boa AR IR Ome dad 6 Hare I I Tee SAS) oi As es Ohi h OF | Wie Cuee oh SE i Vat AR Chay CHS 7 I I ung I 7 Asa thes Colee I Pee B32 Ly > SS Sl ah ee ete) 0.6110 13) 4°39: 2 Oo eee Length—Mean, 191.360 + .943u Breadth—Mean, 54.880 = .431K St. Dev., 17.116 + .666u St. Dev., 7.824 + .305u Coef. Var., 8.945 + .351 Coef. Var., 14.255 + .566 Mean Index, 28.639 per cent.; Coef Cor., 7364 + .0252. 468 JENNINGS —HEREDITY IN PROTOZOA. [April 24, a fresh hay infusion. At once the culture “spread out” greatly, in a way that will appear on comparing Table XIX., for the starving culture, with Table XX., for those twenty-four hours in nutritive fluid. Many of the animals began to grow at once after they were placed in the nutritive fluid, so that the maximum length increased from 176 to 220 microns, the maximum breadth from 40 to 80 microns (see rows 8 and 9, Table XVIII.). Others had not yet begun to increase when the sample of Table XX. was taken, so that Fic. 5. Characteristic forms and sizes from a culture of descendants of D (caudatum form), that had been starved for a week (Table XIX.), then was left twenty-four hours in fresh hay infusion (Table XX.). a@ and 5, Starved specimens. c, d, e, f, transitional forms, becoming large and plump in the abundant food; g, characteristic large, plump form. a@ to g from Table XX. h, characteristic form a week later (Table XXI.); animals becoming thinner again, but retaining the increased length. All > 235. 1908, | JENNINGS—HEREDITY IN PROTOZOA. 469 the minimum size remained as before; and between these extremes all intermediate gradations were found. Fig. 5 shows characteristic forms and sizes from this culture, a and b showing the starving con- dition, while c to f show various stages in the transition to the largest size, one of which is shown at g. As a result of these changes, the variability has increased enor- mously. The coefficient of variation in length has increased in twenty-four hours from 7.003 to 12.767; that for breadth has more than doubled, increasing from 12.473 to 28.879. The mean size has likewise increased greatly, while the ratio of breadth to length has changed from 21.337 per cent. to 28.236 per cent. Perhaps the most striking change is in the correlation between length and breadth. In the starving culture this is but .3906; twenty-four hours later it has become, in the growing culture, .8463—one of the highest coefficients of correlation that I have ever found in Paramecium. It is evident that breadth and length are increasing proportionately, on the whole, so that the inclusion of different degrees of increase in size in Table XX. gives a high coefficient of correlation. Furthermore, the fact that fission had not begun in this lot permits the correlation to remain high; if there were many young included, the correlation would, of course, be lowered. With every increase of 10 microns in length the breadth increases 5.452 microns. Fluid Unchanged for a Week.—Now the same culture was kept for a week in the same fluid. The animals had reached more nearly a condition of equilibrium; the variability, and with it the correla- tion, had greatly decreased, while the mean length had increased (Table XXI., and row 10, Table XVIII.). It is noticeable here, as in many other cases, that the coefficient of correlation decreases when the ratio of breadth to length decreases. Forty-eight Hours in New Culture Fluid—The addition of new hay infusion to the culture just described caused in forty-eight hours a considerable increase in mean length and breadth, while the varia- tion did not change greatly (Table XXII., and row 11, Table XVIII.). Again, as the ratio of breadth to length increases, the correlation between the two likewise increases. Résumé.—Polygons showing the changes in the animals of this series, from the starving condition of Table XIX. to the well-fed 470 JENNINGS—HEREDITY IN PROTOZOA. [April 24, condition of Table XXII. are given in Diagram 6; these, taken in connection with Fig. 5 and with Tables XIX. to XXII. give a good idea of the changes in dimensions and variation that may be pro- 50 45 Ww Un i ) ~ ~ io — — Ww ° —_| | ye. ~ ~ Ss Pfr tal ‘i / Percentage of the Whole iS) iS} fe) wn Dive. “ee ~ 1 : % > aes Poca N ve ‘all _— O° wm ioe SS q Ye. / A ia x V Lge Nl Be Ns 116 128 140982 ' 164% F760. weer coO || 212°) Cea eae Length in Microns. DracrAM 6. Polygons of variation in length for a culture of descendants of the individual D when subjected successively to varied conditions of nu- trition. The numbers above the highest points of the polygons correspond to rows of Table XVIII., in which are given the constants for the different polygons. 8, culture starved a week. 9 (heavy broken line), same as 8, but after 24 hours in fresh hay infusion. 70, same after one week in the same fluid, unchanged. 11, same after 48 hours in fresh hay infusion. +, polygon for combination of 8, 10 and 11, showing its resemblance to the polygon for 9 alone. The correlation tables for these polygons are numbers XIX. to XXII, pages 466, 467. duced in a short time by changes in the conditions of nutrition. Evidently Table XX., taken twenty-four hours after the starving specimens were placed in the fresh hay infusion, is a transitional 1908. | JENNINGS—HEREDITY IN PROTOZOA. 471 condition, including representatives of the small, starving condition, the well grown condition, and intermediate states; it is a sort of a résumé of the variations due to nutrition. If we add together the tables given by the starving culture (earlier than Table XX.) and the two well-fed cultures (later than Table XX.), we get a collection of 450 individuals, in which the variation in length and breadth is about the same as for Table XX. (see row 12, Table XVIII.). For Table XX. the coefficients of variation for length and breadth are 12.767 and 28.879; the corresponding coefficients for the three lots combined are 13.795 and 27.184. Although the animals are all-descended from the same parent and have lived under the same conditions save for the ten days during which these experiments lasted, we find that in the period just men- tioned the polygons of distribution of variations in length have so changed that the one for the end of the ten day period (11, Diagram 6) hardly more than overlaps at one end that for the beginning of the period (8, Diagram 6). Addition of fresh hay infusion causes in these cases an increase in length, in breadth, in variation, and in the correlation between length and breadth. But whether these results shall follow depends upon the previous condition of the animals. This is illustrated by the fact that there is one exception to the statement just made; the variability in breadth decreased in place of increasing in the transi- tion from Table XXI. to Table XXII. The effect of the previous condition is better seen in the experiments of the third series, to be described next. Third Series. A culture of the descendants of D was rather ill-fed, though not starving ; the animals were long and slender (Fig. 6,aandb). Half of these were allowed to remain in the old fluid, while half were placed in fresh hay infusion. After forty-eight hours, a random sample of each set was measured. ‘The measurements of the set in the old fluid are given in Table LIV., the constants in row 13, Table XVIII. The results of keeping the animals forty-eight hours in the fresh infusion are shown in Table LV., and in row 14, Table XVIII. The animals grew plump and multiplied ; the mean breadth increased 472 JENNINGS—HEREDITY IN PROTOZOA. | April 24, from 49.600 microns to 63.160 microns (characteristic form shown atc, Fig.6). But the mean length decreased from 202.280 to 175.320 microns. ‘This is probably due to rapid multiplication; the animals now divide before they reach the length Which they had at first. As a result of the increase in breadth and decrease in length, of course, Fic. 6. a and b, characteristic slender specimens from row 13, Table XVIII. c, characteristic short plump specimen from row 14, Table XVIIL.; produced by allowing those of row 13 to remain 24 hours in fresh hay in- fusion. Descendants of D (caudatum form). All X 235. the mean ratio of breadth to length increased greatly, from 24.593 per cent. to 36.123 per cent. With the increase of this ratio, the correlation likewise increased, as is usually the case. The variation increased, both in breadth and in length. These are the results if we consider separately the two samples, taken forty-eight hours apart. But if we throw them together, look- ing at them merely as a sample of the descendants of D, taken at intervals, we get a surprising effect on the correlation between length and breath. The marked positive correlation in the two samples taken separately disappears and is replaced by a negative correlation. In the first sample the correlation is + .4085; in the second it is + .5376; in the two together it is —.2613. (The constants for the two together are given in row 15, Table XVIII.) The negative correlation is, of course, due to the fact that the nutritive fluid causes the breadth to increase and the length to decrease, so that, on the 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 473 whole, when the two samples are taken together, greater breadth is associated with less length. 2. Proceny oF ¢ (aurelia Form). With the smaller Paramecia, progeny of the small individual c, a similar series of experiments was undertaken. The individual c¢ came from the same wild culture as D; its length, as nearly as could be determined in life, was 120 microns. It was isolated April 8, 1907. Fig. 3 shows some examples of the descendants of c, drawn to the same scale as the figures of the descendants of D. Random Sample.—On June 11 one hundred of the progeny of ¢ gave the measurements shown in Table IV., page 405, the constants being given in row 16, Table XVIII. Effect of Adding Boiled Hay.—On August 9 a fairly flourishing culture of the descendants of c was examined, with the results shown in Table LVI., and in row 17, Table XVIII. To this culture a quan- tity of boiled grass was added; this caused rapid multiplication. Twenty-four hours later a sample of 225 specimens was measured, with the results shown in Table XLIX., and row 18, Table XVIII. The added nutrition has caused the mean length to decrease, while the mean breadth remains nearly the same. This is due to the fact that the main effect of the nutrition was to cause rapid multiplication rather than growth in size. The coefficient of variation in length increased greatly, from 9.736 to 15.279, while the variation in breadth remained about the same, though with a slight decrease. This pecu- liar result is mainly due to the fact that the culture after the addition of the grass (row 18) contains many young specimens, which differ from the adults greatly in length, but little in breadth. As usual, we find that an increase in the ratio of breadth to length is accompanied by an increase in the correlation between the two. Effect of Fresh Hay Infusion—The next day (August 11) another lot from the culture shown in Table LVI. (row 17, Table XVIII.) was placed in a fresh hay infusion and left twenty-four hours. This nutritive fluid caused the animals to become very plump, while at the same time a moderate amount of fission was induced. The results are shown in Table L., and in row 19, Table PROC. AMER. PHIL. SOC..XLVII. I90 EE, PRINTED JANUARY ITI, I909. 474 . JENNINGS—HEREDITY IN PROTOZOA. [April 24, XVIII. As there appears, the mean breadth increased from 33.600 to 47.300 microns. The length, on the other hand, decreased from 123.666 to 114.033 microns. The mean ratio of breadth to length thus increased very greatly, from 27.136 per cent. to 41.455 per cent. The latter is the largest mean index I have ever observed in Para- mecia not selected with relation to the age of the individuals; it is exceeded only by the mean index of the young halves during fission (see Table X.). With the increase in the mean ratio of breadth to length, there is as usual an increase in the correlation between the two dimensions; this reaches the unusually high value of .81 52. The nutritive fluid left the variation in length about the same, but con- siderably decreased the variation in breadth. This is undoubtedly due to the fact that before the hay infusion was introduced some of the specimens were well fed, some poorly fed, as the chances of the daily life determined; while after the infusion was introduced ail were well fed, so that there was less variation in breadth than before. Characteristic forms after the infusion was introduced are shown in Fig. 3, a to c (page 423). The facts in these cases are nearly parallel with those observed in the third series of experiments on the progeny of D (Table XVIIL., rows 13-15). If we combine the two samples of c (row 20, Table XVIII.), as we did those of D, the effect is, as in the case of D, to decrease greatly the correlation between length and breadth But in the present case the very high positive correlation of the two samples taken separately is not entirely overcome by combining them, though the correlation falls to .1758. The actual numerical coefficient just given is the resultant of a number of conflicting factors. In the two samples taken separately greater length is associated on the whole with greater breadth, giving high positive correlation, which in pass- ing from Table LVI. to Table L. an increase in breadth is associated with a decrease in length, tending to diminish the correlation. The facts show clearly that the observed statistical correlation does not involve any necessary and constant relation of the one dimension to the other; both dimensions depend on various factors, which some- times act in the same way on both, sometimes differently. Combining the two samples of c (as in row 20, Table XVIII.), gives, of course, increased variation, illustrating, like most of our 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 475 results, the fact that a definite coefficient of variation cannot be con- sidered characteristic of a given species or race. The observed variation depends on many factors. Conjugating Culture.—The progeny of c I divided into two sets, both of which were kept in larger culture vessels and maintained by adding boiled hay at intervals. September 25 one of these cultures was found to be undergoing’ an epidemic of conjugation (though, of course, all were progeny of a single individual). The details regard- ing the relation of conjugation to the phenomena we are studying are to be taken up in a later communication, but I will give here the essential facts regarding dimensions and constants of variation, in order that our picture of the changes undergone by the c line may be as complete as possible. A random sample of the non-conjugants of this conjugating culture gave the results shown in row 21, Table XVIII., and in Table LVII. The mean length (158.800 microns) was considerably greater than has been observed in any other culture of c. Whether this fact has any relation to the occurrence of conju- gation, or whether it is merely a matter of the environmental condi- tions must remain for the present a question. Scarcity of Food After Conjugation.—This conjugating culture was allowed to stand five days. All conjugation ceased and the food began to get scarce. Now a sample gave the results shown in row 22, Table XVIII., and in Table LVIII. The length had decreased from 158.800 to 129.640 microns. Breadth likewise decreased, though not in so great a proportion as length, so that the ratio of breadth to length increased. As is usual when this ratio increases, the coeffi- cient of correlation likewise increased. Variation in Different Divisions of the Same Pure Line on the Same Date.—After the observations just described, the two cultures composed of the progeny of c were maintained for several months. On January 23, 1908, samples from each were measured, giving the results shown in rows 23 and 25, Table XVIII. As is evident, the two differed considerably. The details do not demand attention, save that in one of these old cultures (row 23, and Table LIX.) the coefficient of correlation between length and breadth was the highest I have ever observed in Paramecium, reaching .8500. Both these cultures were flourishing and well fed. 476 JENNINGS—HEREDITY IN PROTOZOA. [April 24, Effects of Lack of Food.—From the culture shown in row 23, Table XVIII., a large number of specimens were removed and placed in a small watch-glass, which was allowed to stand for two days. The food decreased rapidly and the animals became smaller, giving the results shown in row 24, Table XVIII. The mean length had decreased 10.174 per cent. ; the mean breadth 33.024 per cent. These were now allowed to stand for three weeks more in the watch-glass, without adding food. At the end of this time they were in the extremes of starvation, and only 37 specimens remained of the many hundreds originally present. These 37 gave the results shown in row 26, Table XVIII. As compared with the original condition of row 23, the mean length had decreased 30.638 per cent., the mean breadth 55.886 per cent. A peculiar fact is that this starving culture shows a very high coefficient of correlation between length and breadth (.8018), while in our other starving cultures this has not been the case (see rows 6 and 8, Table XVIII.). From the culture of large specimens shown in row 23 another lot was removed January 30 and kept in a small watch-glass, new hay infusion being added at intervals. In spite of this addition of new food material, and the fact that they continued to flourish and multiply, these decreased in length even more than in the starving culture, the mean being 100.320. This is the smallest mean length observed in any lot of the c line. The data for this lot are given in row 27, Table XVIII., and in Table LX. 3. SUMMARY ON THE EFFECTS OF ENVIRONMENT. The facts given above show that the nature of the environment affects greatly the dimensions, proportions and variations of Para- mecium, and that these effects are produced with great ease and rapidity by such changes as are common in any culture of these infusoria. Some of the more important effects may be summarized as follows: Effect on Length—Under the influence of varied nutritional con- ditions the length varies extremely. In the line descended from the individual D the mean length varied under different conditions from 146.108 to 202.280 microns—the difference being 38.445 per cent. of the smallest mean length. In the c line the variation in mean length 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 477 under the influence of the environment was from 100.320 to 158.800 microns, or 58.293 per cent. of the lowest mean. The extreme lengths in each line, of course, differed still more; in the D line the extreme variation in length was from 104 to 256 microns, or 146.153 per cent. of the least length; in the c line it was from 73.3 to 200 microns, or 172.851 per cent. of the minimal length. Effect on Breadth—tThe breadth (the thickness of the body) varies under different environmental conditions more readily and in a higher degree than does the length. In the D line the mean breadth varied in different cultures from 31.180 to 64.880 microns, or by 108.08 per cent. of the lowest mean; the extreme variation in breadth, under different conditions, was from 20 to 88 microns, or 340 per cent. of the minimal breadth. In the c line the mean breadth varied under different conditions from 23.892 to 54.160 microns, or by 126.69 per cent. of the lowest mean; the extreme variation in breadth was from 16 to 84 microns, or 425 per cent. of the minimal breadth. The greater variability of the breadth, as compared with the length is seen in the coefficients of variation of the single cultures. The largest coefficient of variation for length is 15.279, while for breadth it is 28.870. Relation of Length to Nutrition.—In general, increased nutrition increases the length. But the result is not always the same, because increased nutrition has two main effects: to increase directly the size of the adults, and to bring about multiplication. The latter effect, of course, decreases the mean length of the individuals of a culture, since it induces the presence of many specimens that are young, and therefore small. Increase in mean length due to added nutrition is seen in Table XVIII, rows 8 to 9, 10 to 11. Decrease in mean length, due to added nutrition is seen in the same table on comparing rows I and 2; 3 and 4; 13 and 14; 17 and 18. This decrease is due to the fact that in the nutritive fluid the animals divide before they reach the length of those in the poor fluid. Decrease of length, due to decrease of nutrition, is seen in Table XVIII., by comparing rows 2 and 6; 7 and 8; 21 and 22; 23 and 24; 23 and 26. Relation of Breadth to Nutrition—The relation of breadth to nutrition is simpler than that of length; in all cases increase of nutri- 478 JENNINGS—HEREDITY IN PROTOZOA. [April 24, tion increases the breadth; decrease of nutrition decreases it. The response of breadth to changes in nutrition is immediate and very marked. Within twenty-four hours increased nutrition caused in the D line an increase of 49.724 per cent. in breadth (rows 8 and 9, Table XVIII.) ; in the ¢ line it caused in twenty-four hours an increase of 40.778 per cent. (rows 17 and 19, Table XVIII.). But the decrease of breadth with decrease of nutrition does not vary directly with the time; when plump individuals are left without food, they decrease much more rapidly at first than later. Thus, in the series shown in Table XVIII., rows 2, 3 and 6, the breadth decreased in the first forty-eight hours 21.324 microns, or 32.867 per cent.; in nine days more of lack of food the breadth decreased only 5-476 microns, or 8.440 per cent. more. Proportion of Breadth to Length.—Since changes in nutritional and other conditions act more readily and more strongly on breadth than on length, and since the same agent may increase the breadth while decreasing the length, the proportion of breadth to length varies greatly under different conditions. The mean index, or ratio of breadth to length, varies in different cultures of the D line from 21.337 per cent. to 36.123 per cent.; in the c line from 23.067 per cent. to 41.455 per cent. Since the breadth is more dependent on nutritive conditions than is the length, we find the lowest ratio of breadth to length in the starving cultures (rows 8, 26, Table XVIII.) ; the highest ratio in well-fed cultures (rows 2, 14, 19, Table XVIII). An increase of nutrition causes uniformly an increase of the ratio — of breadth to length; a decrease of nutrition has almost uniformly the reverse effect. A single exception to the relation last mentioned is seen in the change from row 21 to row 22, Table XVIII.; here other causes, connected with conjugation, were probably at work. Whenever the mean breadth increases, the mean ratio of breadth to length likewise increases. (The only exception is the case just men- tioned, where conjugation was involved.) It must be understood that this does not mean that in all cases the mean ratio of breadth to length varies directly with the mean breadth; if we compare rows 6 and 7, Table XVIII., for example, we find that this is not the case. But whenever, as a matter of experimental procedure, the mean breadth was caused to increase, the mean ratio of breadth to 1908. | JENNINGS- HEREDITY IN PROTOZOA. 479 length likewise increased. This is due to the two facts mentioned in the first sentence of this paragraph. Effect of Environment on Variation.—The amount of observed variation, as measured by the coefficient of variation, depends largely on environmental conditions; this is true both for length and for breadth. In the D line the coefficient of variation for length varies in different cultures from 6.821 to 13.262;° for breadth it varies | from 8.896 to 28.879. In the c line the coefficient varies for length from 7.134 to 15.279; for breadth from 10.700 to 24.291. The effects on the coefficient of variation of changes in nutrition vary much in different cases ; increased nutrition sometimes increases the coefficient, sometimes decreases it, sometimes produces first one effect, then the other. There are evident physiological reasons for the different effects. In a starving culture the first effect of rich nutrition is to cause many of the individuals to increase in size, while those individuals in which the effects of starvation had gone far do not at first take food and change. Hence there is a great increase in the coefficients of variation; in changing from row 8 to row 9 (Table XVIII.) both coefficients approximately doubled in twenty-four hours. Later, though the animals were kept in the same fluid, the coefficients decreased again—all of the specimens having reached more nearly a condition of equilibrium. If the animals are fairly well fed before the additional nutrition is met, an early effect is to cause rapid multiplication; the consequent presence of both young and old individuals in the culture increases the coeffi- . cients of variation, and particularly that for length. An example of this is seen in the change from row 3 to row.4, Table XVIII. A little later, when the multiplication has ceased, the coefficients of variation become small again. The coefficients of variation are likely to be small in starving cultures, owing to the fact that there is little multiplication and the adults have reached a condition of rela- tive equilibrium. By taking into consideration the immediate and the remote effects of a given agent on growth and multiplication, its effects on the coefficients of variation usually become intelligible. * °Of course the cultures contain specimens in all stages of growth; as we have previously seen, the coefficient of variation becomes much less when the animals are selected with reference to age. 480 JENNINGS—HEREDITY IN PROTOZOA. [April a4) It is not necessary to emphasize the fact that since different environmental conditions produce different dimensions, the coeffi- cients of observed variation will be much increased by throwing together specimens from different environments, or those taken at different times from the same culture. Examples of this are seen in rows 12, 15 and 20, Table XVIII. The question may be asked, How can we account for the large coefficients of variation in given lots, taken all from the same envir- onment (as in the various “rows” of Table XVIII.)? Surely, it may be said, the age differences among the individuals are not suffi- cient to account for coefficients of 12, 13, 20, etc., such as we actually find. This is undoubtedly true, and it becomes still more striking when we consider cases like Table XLI. (appendix), where the indi- viduals are all of practically the same age, and all come at one time from the same small watch-glass of hay infusion, yet we find the coefficients of variation to be respectively 6.389 and 14.615. The considerable variation is to be understood only by realizing that even a small mass of fluid constitutes a relatively large and varied envir- onment for Paramecium. A watch-glass of hay infusion is a micro- cosm to this animal. Bacteria gather on the surface, while they may not be found on the bottom or through the middle. The bac- terial zodgloca may become thicker at one edge than at the other, owing to the accidents of the original distribution of the seed bacteria or of the infusoria. Some of the Paramecia thus get more food than the others, perhaps at a critical period of growth; they thus get a start, which enables them perhaps to obtain more food than the others, even under uniform conditions. Some of the individuals get crowded away from the bacterial zodgloea, and remain against a rough spot on the glass instead, where they get no food. In short, even in a few drops of water the conditions are not uniform through- out; some of the animals are well nourished, others poorly nour- ished, and the results show in the variations of their measurements. The question whether some of the variations in such cases are not congenital and hereditary will be taken up later; we shall find little evidence that this is the case. : It is clear that no particular coefficient of variation can be con- sidered characteristic of a particular race, except as the conditions 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 481 are very precisely defined. If all conditions of environment and growth were made absolutely the same, there is reason to believe (as we shall see farther) that for a given line (descended from a single individual) the coefficient of variation would be very close to zero. Its actually observed value in a given lot then depends almost entirely on environmental and growth differences. Effect of Environment on Correlation.—The observed correlation between length and breadth varies greatly under different environ- mental conditions. In the D line the coefficient which measures correlation varies in different cultures from .3906 to .8463; in the ¢ line from .4141 to .8500 (see Table XVIII.). Such differences are easily and quickly produced by environmental changes ; thus the two extremes just mentioned for the D race were found in samples of the same lot of Paramecia taken twenty-four hours apart—one before, the other after, the addition of a nutritive fluid. The correlation between length and breadth expresses the accu- racy with which length and breadth vary proportionately. The actual proportion of one to the other, in a given lot, is, of course, of no consequence; length and breadth might be the same, or one might be 50 per cent. or I per cent. of the other; the correlation would still be complete (1.000) provided this same proportion were main- tained throughout the particular lot examined. Any factor which causes the proportion of breadth to length to vary in a given lot, of course causes the correlation to fall below 1.000. If in a given lot many different ratios of breadth to length are represented, the cor- relation is, of course, lowered. In such a lot, any factor which tends to make the proportion of breadth to length more constant, of course, increases the correlation. Examining the various factors which have the effects just men- tioned, we find that the observed correlation depends upon many things. (a) In considering the effects of growth (page 455), we saw that the proportion of breadth to length differs in different stages, Some of the effects of the environment on correlation are due to its effect on multiplication and growth. (b) Certain environmental agents (as increased nutrition) increase the breadth while decreasing the length. Now, if this happens at 482 JENNINGS—HEREDITY IN PROTOZOA. [April 24, the same time and in the same proportion in all the individuals, then at any given moment the coefficient of correlation will, of course, not be altered by it. But if for any reason the changes occur more quickly or strongly in certain individuals than in others (as is usually the case), then, of course, the coefficient of correlation will be decreased. Or, if we throw together individuals taken at different stages of the process, the correlation becomes greatly decreased; it may even become negative. For examples, see rows 15 and 20, Table XVIII. (c) Even if a given agent causes a change in the same direction (e. g., an increase) in both length and breadth, the inclusion of different stages in the process may reduce the correlation (if it is already high). This will occur (1) if the two dimensions are not changed proportionately to each other, and (2) if the change in a given dimension varies at different stages of the process. Both these conditions, as we have seen, are fulfilled in the changes in dimensions induced by the environment. Under almost any environmental change breadth is altered more than the length. Furthermore, when nutrition is decreased, breadth decreases more rapidly at first than later. The inclusion of different stages of the process in a collection therefore results in the inclusion of various different proportions of breadth to length—lowering the correlation. (d) If the correlation is already low, indicating the presence of many different ratios of length to breadth, then varied changes in these ratios may compensate some of the existing differences. causing an increase in the correlation. Whether this shall or shall not occur depends upon the condition of affairs before the changes are made, and on the nature of the changes themselves. A special case of this comes up in the next. (e) When a culture containing thin, poorly fed individuals is given added nutriment, the correlation between length and breadth increases (compare, in Table XVIII., rows 1 and 2; 8 and 9; 10 and II; 13 and 14; 17 and 18; 17 and 109, etc.). This is because, when fresh nutriment is added, the thinnest, poorest-fed individuals nat- urally take more food than do the individuals that are already plump and well-fed; they therefore increase most in breadth. As a result, existing differences in breadth are compensated; all the animals take 1908. | JENNINGS—HEREDITY IN PROTOZOA. 483 on that relative proportion of breadth to length that belongs to well-fed specimens. Thus, we find almost throughout that an increase in the ratio of breadth to length is accompanied by an increase in the coefficient of correlation ; a decrease in the ratio of breadth to length by a decrease in the coefficient of correlation. Examining these two constants, in the last two columns of Table XVIII., we find this relation to hold in every case of experimental procedure save one. (In the change from row 3 to row 4 it does not hold; this is due to another factor, to be taken up later.) If without regard to experimental pro- cedure, we merely compare the mean index (or ratio of breadth to length) with the coefficient of correlation, we find the relation a little less general, though still marked; a large mean index is usually accompanied by a high coefficient of correlation. _Since, as we have previously seen, greater breadth is usually accompanied by a higher mean index, it follows that greater breadth is likewise usually accompanied by a higher correlation between breadth and length. This is, on the whole, evident on inspection of Table XVIII., though since other factors are involved, the relation is not without exception. But in general, broader specimens tend to show a more constant proportion of breadth to length than do thin ones. (f) In poorly-fed cultures, as we have just seen, the breadth is apt to be variable in proportion to the length (giving low correla- tion) because some of the individuals get more food than others. But if all are reduced to an actually starving condition, then this source of variation is removed, and we may again get high corre- lation between breadth and length. This condition appears to be realized in row 26 of Table XVIII. Here a large culture had been reduced by starvation to a population of but 37, and these give the very high correlation of .8018 + .0396. (g) When a given agent causes rapid multiplication, so that the sample taken includes many different stages of growth, with their different proportions of breadth to length, the correlation becomes low. This is the reason for the marked decrease in correlation in changing from row 3 to row 4 in Table XVIII. All together, it is clear that no particular coefficient of correlation ‘ 484 JENNINGS—HEREDITY IN PROTOZOA. [April 24, can be taken as characteristic of a particular race of Paramecia; certainly not without very precise definition of the conditions. It appears probable that if all conditions of environment, growth, food taken, etc., could be made absolutely the same for individuals derived from the same ancestor, the coefficient of correlation would be close to 1.000. By varying these conditions any degree of positive cor- relation, down to zero, and many degrees of negative correlation can be attained. V. INHERITANCE OF SIZE. Having examined the effects of growth and of environment on size and form, we are now prepared to investigate how far these are determined by internal factors, handed on from parent to progeny. Without such a preliminary study of growth and environmental action it would be impossible to investigate successfully the heredity of size and form. We have already seen that not all differences in size are due to growth and environment; in the first culture examined (Table L., page 398) there were at least two sets of individuals of characteris- tic different sizes, and these differences in size are lasting. Progeny of the two typical individuals D and c, from these two sets, still retain their characteristic relative sizes after more than a year of culture under all sorts of conditions. The differences between these two sets are about the same as those which have been described as distinguishing two species, D corresponding to the accounts of Paramecium caudatum, c to Para- mecium aurelia. The next problem is to determine whether there are still other races of Paramecium, distinguishable on the basis of differences in size, independently of the environment. Can we by selecting individuals of differing sizes isolate races of corresponding sizes? Can we find races of all sorts of sizes intermediate between the largest and smallest adult representatives of such a heterogeneous culture as is shown in Table I.? The clear grouping of the culture of Table I. into two sets seems to indicate that we have present simply two races or species. My °° Of course tf all variation disappeared, as would perhaps be the case, then the concept of correlation would have no further application. aook} JENNINGS—HEREDITY IN PROTOZOA, 485 first experiments consisted of attempts to break the two lines derived respectively from D and c into other races of different sizes by selec- tion and breeding of individuals of different sizes. This led inci- dentally, as we have seen, to the study of the effects of growth and environment on size; it was found that the observable differences between different members of either race were due to these factors, so that selection of such members did not lead to the establishment of races of different sizes. The results of a large amount of time- consuming work along this line, done before the investigation of growth and environmental action, were throughout negative.’ As a result of this work, I was disposed toward the belief that the characteristic sizes of D and c represent conditions of stability, which have properly been distinguished as two species, and that races of other sizes were not to be found or produced. But the work thus far has, of course, been based on “ pure lines,” in the sense in which that expression is used by Johannsen (1903, 1906). The lines D and c are each derived from a single individual, reproducing asexually, so that no admixture from outside has entered them during the experiments. Now, while it appears difficult or impossible to produce other races within these pure lines, there remains, of course, the possibility that still other lines exist in nature. Can we find in a “wild” culture, by proper selection of differing individuals, still other races of differing size? This was the question next investigated. ‘ I. SELECTION FOR DIFFERENT RACES IN A WILD CULTURE. (a) Races Isolated from Cultures Not Conjugating. Attempts to separate out other races than those represented by D (“caudatum form”) and c (“aurelia form”) were first made with a wild culture which I called OJ. This culture developed in decaying vegetation from a marsh. It contained two well marked sets of individuals: (1) very large individuals, corresponding in many respects to the D line, but with a mean length on January 3, 1908, of 238.280 microns; these we will designate E; (2) smaller ™To the experiments on selection within a pure line we return in a later section. 486 JENNINGS—HEREDITY IN PROTOZOA. [April 24, individuals corresponding in many respects to the c line, with a mean size on November 14, 1907, of 140.133 microns. These two sets occurred mixed, but each reached its maximum development at the dates mentioned. Isolated samples of the two sets retained their characteristic differences in size, just as ve pha in the case of D and c. But the interesting condition showed itself in the smaller set. An:ong these were individuals of such different sizes, that in spite of our knowledge of the great differences produced by growth and environment, it seemed worth while to try to isolate and breed them. In a random sample of 60 specimens the length varied from 96 to 176 microns—the smaller sizes being grouped about 120 microns, the larger about 160 microns. Accordingly, on November 9, 1907, I separated two lots, one containing ten of the smaller specimens, the other ten of the larger ones. These were placed in watch-glasses with equal quantities of the same culture fluid, and kept under identical conditions, where they were allowed to multiply. One week later (November 16) thirty specimens measured from each showed mean dimensions of 125.600 X 36.200 microns for the progeny of the larger ten, 96.400 X 30.00 microns for the progeny of the smaller ten. On November 27, a random sample of 100 from each gave for the progeny of the larger ten, dimensions of 134.320 X 36.280 microns; for the smaller set, 92.240 X 26.920 microns. Thirty-seven days later (January 2, 1908 ) the two lots still showed their characteristic differences, though cultivated under identical conditions. The mean dimensions of the two sets (from random samples of 100) were now 134.360 X 33.440 microns (for the ae and 104.208 X 26.583 microns (for the smaller ). Thus, we have clearly two sets, with differences in size persisting from generation to generation (in spite of fluctuations in each due to environmental changes), and both falling, in a general way, in the dimensions previously found for the line c. It is evident, therefore, that D and ¢ did not represent the only existing different lines. Since the two sets under experimentation had come each from ten individuals which may be of heterogeneous origin, I isolated from each, as soon as it was evident that they were retaining their 1908.] JENNINGS—HEREDITY IN PROTOZOA, 487 differences, a single characteristic individual. This was done on November 13. The specimen from the larget set I called g; it measured approximately 130 to 140 microns in length. The speci- men from the smaller set I called 7; its length was about go to 95 microns. These two individuals were kept under the same condi- tions and allowed to multiply. The small specimen 7 multiplied more rapidly than the large one g. On November 16 there were but seven progeny of g, while 7 had produced a large number. Two typical specimens of g were killed and gave measurements of 160 X 48 microns and 164 X 56 microns. Five typical specimens of 7 ranged in size from 92 & 36 to 128 X 44 microns, with a mean of 103.2 X 39.2. Evidently, therefore, the progeny of g and 1 tend to retain the differences in size characteristic of the parents. The two lines were kept for a long time, under the same conditions; at intervals random samples were measured. The measurements at different dates, with the number of specimens on which they are based are given in Table XXIII., p. 488. (The small numbers of specimens employed on certain dates are due to the fact that only a small number ex- isted at that time.) The great fluctuations in the dimensions of each line will of course surprise no one who has examined that part of this paper which deals with the effects of the environment. These fluctua- tions are due mainly to differences in nutritional conditions. At intervals it was necessary to add new culture fluid; the dimensions in both lines thereupon rose at once; they then gradually declined till new fluid was added. Details on this matter are not necessary for our present purpose. The important fact is, that in spite of all fluctuations, the lines g and 7 retained throughout the three months in which they were under observation their characteristic relative sizes. Multiplication was probably at the rate of about one fission a day, so that the table represents 90 to 100 generations. We have here two lasting races comparable to the two races from our first culture, which we called Dandc. It is clear that neither g nor i is identical with D, since the latter is much larger; whether either is the same as ¢ we shall inquire later. 488 JENNINGS—HEREDITY IN PROTOZOA. [April 24, x TABLE XXIII. Comparative Sizes in Microns of g and i and their Progeny at Different Dates, when Cultivated under the Same Conditions. g and Its Progeny zand Its Progeny. Pate No. of Mean Mean No. of Mean Mean Specimens. Length. Breadth. Specimens, Length. Breadth. 1907 Nov. 13 I 130-140 35-40? I 90-95 30-40? £05.00 2 162.000 52.000 5 103.200 39.200 eae: 7 140.000 40.000 12 103.666 35.666 eet 30 129.333 34-933 30 838.268 30. 268 6 26 100 137.120 38.720 100 99.560 28.200 Dec. 7 61 120.590 41.110 96 98.709 34.208 pasa es 17 127.059 38.588 23 98.608 29.739 hd ale So) 40 112.600 31.300 64 86.756 22,062 1908 ; Jan. 2 100 146.640 40.600 100 106,680 26.400 Feb. 5 57 116.912 36.070 43 93.583 27.500 It will be recalled that in the original culture from which came g and i, there was a still larger set which we called E. Ten of these were selected and cultivated under the same conditions as g and 1. They retained throughout their much larger size (numerical results are given later), so that from this culture we have isolated three lines or races which retain their differences in size under the same external conditions. At this period, then (January 1, 1908), I had in the laboratory a number of lines or races which had been studied with care. These formed two sets, so far as our knowledge of them up to this point is concerned. The two lines, D and c, from culture J, were clearly distinct even under identical conditions. The three lines, g, i and E, from the second wild culture OJ, are likewise clearly distinct from But the relation of g, i and E to D and c is uncertain; we may have on hand five distinct lines, or only four, or three. To determine whether any of these five lines are identical, it is necessary to cultivate all five under the same conditions. A certain number must be selected from each; these must be brought into the same culture fluid and allowed to multiply in the same environment. each other. It is extraordinary what difficulties are presented in carrying out this apparently simple plan. The different lines have become adapted to certain diverse nutritive conditions; if now they are brought at once into the same culture fluid, some of them die. In the present case, g and 7 had been living in comparatively fresh hay infusion, D and ¢ in different old hay cultures, E in a culture of decaying pond weeds. When all were brought into fresh 1908 ] JENNINGS—HEREDITY IN PROTOZOA. 489 hay infusion, E died at once, c after a day or two; D multiplied slowly, then died in the course of a week or so, while g and i throve and multiplied. It was therefore necessary to bring the different lines gradually into the new fluid, by mixing some of it with the fluid in which they lived, increasing the proportion of new fluid at intervals. This was found to be a very deli- cate undertaking. Certain of the lines would thrive for a time, under this procedure, then would begin to degenerate; in this way much time was lost, Finally, however, the different sets were induced to thrive in the same hay infusion. Procedure Necessary for Making the Conditions Identical for Different Lines——The procedure followed, in order to be certain that the cultural con- ditions were the same for all, was as follows: From each race ten typical individuals were selected. These were mixed with gradually increasing amounts of hay infusion, in the way just set forth—while at the same time of course they multiplied in number. After they had all gotten accustomed to the infusion, it was necessary to take measures to assure the identity of the solutions in which the different sets were living. For this it is not sufficient merely to transport the individuals to definite quantities of the same nutritive solution. For up to this point each set has been living in a solution which has received an admixture of the original culture for that set. Now, these different original cultures contained different kinds of bacteria. On transferring the infusoria to the hay infusion, they of cousse carried some of their own bacteria. By repeated changes the number of bacteria introduced could be mitch reduced. Nevertheless different kinds were brought in in different cases, so that we still have the different lines in cultures of diverse bacteria. From this fact naturally diverse chemical properties may develop in the different cultures, though the basic nutritive solution is the same. These diverse chemical properties would of course modify the organisms, making it impossible to compare them with regard to inherited size. To make the conditions of existence the same, it is not sufficient to attend merely to the basic fluid; the bacteria in the fluid must also be the same. This is a principle of wide practical importance in all experimental work with such infusoria. It is not a mere theoretical requirement; death frequently results from the introduction of a certain kind of bacteria into a certain culture, while another culture of identically the same fluid flourishes, be- cause the bacterial infection is different. This requirement was met in the following way: After the different sets had become acclimatized to the same hay infusion, ten of each were removed with a fine capillary pipette, and washed twice in fresh hay in- fusion. The second washing of the different sets was done in the same mass of fluid,—a small watch-glass full. The different sets might of course each carry with them a few of the bacteria characteristic of their original culture, After all had been washed in the same mass of fluid, this fluid would of course be infected with bacteria from all the different sets. Now, after the washing was finished, a definite quantity of this fluid in which all had been washed was added to the final culture fluid for each lot. Thus each lot of ten is in the same quantity of the same nutritive fluid, PROC, AMER, PHIL, SOC. XLVII. 190 FF, PRINTED JANUARY 12, 1909. 490 JENNINGS—HEREDITY IN PROTOZOA. [April 24, and infected with the same bacteria as all the others. All are kept in watch- glasses of the same form and size, close together in the same moist chamber. Any characteristic differences in the resulting progeny must then be due to conditions within the animal, and not to differences in the environment. If we reach the same result, not merely in one experiment, but in a series con- ducted in this manner, we can be sure of our results. Cultures of the five lines, D, c, g, 1 and E, prepared in the way just described, were set in progress January 19, 1908. In order to determine with certainty how much effect possible environmental differences might have on the results (as well as for certain other purposes), two lots each of D, g and i were used. If the two lots of g, for example, show differences as great as those between g and c, then, of course, we have no ground for considering g and ¢ inher- ently different ; the environmental differences account forall. These lots were allowed to multiply till February 5. Then a sample of each was killed and measured. Now a new lot of ten of each set was prepared by the methods given above, and the animals were again allowed to gnultiply till February 15, when samples were again measured. It will be recalled that E is a lot derived from ten specimens of possibly diverse ancestry, from the culttire OJ, with an original mean length of 238.280 microns; that the line D has shown in repeated determinations a highest mean length of 202.280 microns (Table XVIII.) ; that c, g and i are smaller lines, derived from single individuals; g is known to be larger than i, but the relation of c to these is unknown. The results of these breeding experiments are given in the fol- lowing Table XXIV. The experimental results given in this table show certain things clearly. 1. The method of culture is adequate for bringing out the inher- ent differences in different lines without confusion due to environ- mental effects. This is shown by the fact that when two cultures are made from certain single lines, these show themselves after breeding for many generations to be nearly identical, while the different lines give diverse results. In only one case (D on Feb- ruary 15) is there a notable difference btween the two samples of a single line, but this is much less than the difference between that line and any other. 1908.] JENNINGS—HEREDITY IN PROTOZOA. 491 TABLE XXIV. Mean Dimensions in Microns of the Five Lines E, D, c. g and i, when Culti- vated under the same Conditions, January 19 to February 5 and February 5 to February 15. Dimensions of E. Dimensions of D. Dimensions of c. Date. Be st BE g a 8a Ba $ 33 S$ 4s a = A = 3 | (1) 169.754><46.877 169.895 X 43-579 180.240 46.880 100| (2) 173.240><49.760 Feb. 5/ 43 169.395 X52.930 99.667 26.333 - 8 6S = iS) wm Feb. 15 |100 200. 320>X52.400 a 00| 100.320>26.480 Feb. 27 |100 172.040 55.520 |100 175.360X47.160 Dimensions of g. Dimensions of 7. se 33 Date. 2s as 3 5 5 $ a as Feb. 5 50 114.720 33.920 50) (1) 92.000 26,960 57| (2) 116.91236.070| 48) (2) 93.583><27.500 Feb. 15 |100 125.240 35.440 100) 95-440 30.040 2. At least four distinct lines are present, D, c, g and 1; these maintain their relative different sizes throughout the experiments, which lasted about twenty-five generations. 3. The lines E and D are nearly or quite the same. On February 5 they show nearly the same measurements, but on February 15 there was a marked difference. To test the meaning of this these two were cultivated twelve days more; then on February 27 they gave again nearly the same measurements. It will doubtless be safest to consider them the same. We have now, therefore, four different lines or races of Para- mecium, characterized by persisting relative differences in size. One of these (D and £) belongs, from its size, to the “caudatum group”; the other three are much smaller and fall in the “ aurelia group.” Of these, g is the largest, 7 the smallest, while c is inter- mediate. Under a similar change in the environment these all change in a corresponding way, as is shown by the fact that on February 15 all were somewhat larger than on February 5. It may be noted that 492 JENNINGS—HEREDITY IN PROTOZOA. [April 24, the differences in size among these four lines were very evident to the eye on inspection with the low power of the microscope, and that the difference was clearly present at all periods between the dates when the measurements were made. The measurements merely make precise what is evident to the eye without them. Before attempting to determine whether still other lines can be isolated, and particularly whether it is possible to fill the wide gap between the caudatum group and the aurelia group, another question must be investigated—a question which strikes at the foundation of our conclusions up to this point. This is the question of the relation of these lines of diverse size to conjugation and the life cycle. (b) Are the Lines of Different Size Merely Different Stages in the Life Cycle? Calkins (1906) and others have set forth the fact that Para- mecium and other infusoria show different dimensions in different. stages of the life cycle—the cycle which begins with conjugation, extends over many generations of reproduction by fission, and ends with another conjugation. The question arises, therefore, whether our lines of diverse dimensions are not merely different stages in the life cycle; whether they would not, if brought to the same stage of the cycle, show the same dimensions. This possibility must be investigated before we proceed farther. The details of the relation of conjugation and the life cycle to variation, inheritance, etc., are to be dealt with in a separate paper of this series. But since the question which stands at the head of this section is an absolutely fundamental one for the proper inter- pretation of the results of the present paper, it must be dealt with here. To answer this question, it is evidently necessary to proceed as follows: Cultures showing epidemics of conjugation must be exam- ined for conjugating pairs of diverse-sizes. If such are found, the individuals must be isolated-and allowed to multiply, in order to determine whether the progeny retain the diverse sizes characteristic of the parents. If from a conjugating culture we can obtain diverse lines standing all in the same relation to conjugation and the life cycle, then evidently our diverse lines represent something more 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 493 than different stages in the life cycle. The problem also can be attacked in certain other ways, which will be described. The relation of diverse sizes to conjugation and the life cycle was studied with special thoroughness in the case of a culture in which there was an epidemic of conjugation January 29, 1908. This culture was found in decaying vegetation from a small pond near Baltimore; I called it culture M. Table LXI. (appendix) shows a random sample of this culture, including both conjugants and non- conjugants ; of the 238 specimens in the table, 38 were conjugants, 200 non-conjugants. From this culture M a large number of pairs were isolated, for various purposes, and allowed to multiply. Without going here into the details of the experiments, on February 21 I had from this cul- ture eight sets or lines, each descended from a single equal pair or a single ex-conjugant; these lines were designated in my notes La, G1, At, A2,I,C2,FrandF2. (The designations are the same as those given to the original pair or individual from which the lines came.) In addition to these eight “ pure lines,” I had two cultures derived each from eight pairs of conjugants of approximately the same size; these were called Kr and K2. A final culture was derived from ten small, nearly equal, non-conjugants from the same culture; it was designated H. It is, of course, unfortunate that it is not possible to measure accurately the original living individuals from which the different lines are derived, but this will not alter in any way the results on the problem in which we are at present interested. The essential question is whether the lines derived from the different pairs or individuals are identical or diverse in size. _ These various cultures were kept, so far as possible, in the same nutritive fluid and under the same conditions. Marked differences in size were apparent on examining the different sets with low power of the microscope. On February 21 fifty individuals of each of these eleven different sets were brought, with all the precautions mentioned on page 480, into the same culture fluid, while at the same time fifty specimens each of D and g of our earlier pure lines (see page 491) were brought into the same fluid. These were all allowed to multiply till February 26, when a random sample of 100 or more 494 JENNINGS—HEREDITY IN PROTOZOA. (April 24, of each was killed and measured. Later, on March 7, twenty indi- viduals were taken anew from each of these thirteen lots, brought again with elaborate precautions into the same culture fluid, kept under the same conditions and allowed to multiply, part till March 13, part till March 19, when other samples were killed and measured. From our previous extensive experience with 7 and g (Table XXIII, page 488) and with five lines of Tables XXIV. (page 491), we can be assured that two sets of measurements taken at such intervals will give us reliable data as to the existence of any considerable lasting differences among the different lines. The results of the measurements of the thirteen different sets are given in classified form in Table XXV. TABLE XXV. Mean Dimensions in Microns, of the Thirteen Sets Described in the Text, after Cultivation under the Same Conditions, February 21 to February 26, and March 7 to March 13 (or March 19). (The conditions before; and in intervening periods were essentially the same, but elaborate pre- cautions were taken for the periods specified). All are from the con- jugating culture M, of January 20, save the last two sets. LO race] uD me. | BE EE). Bees a3] Line. Es g February 26. S g arch 13. g Gi arch 19. as as As (1) Descendants of Pairs. £2 | 100] 206.360 < 60.840 | I100| 220.560 59.960 GI | 100} 201.400 X 52.400 | 100| 210.960 < 52.200 Atl | 100| 193.560 X 51.840 | 100| 203.640 * 52.560 A2 | 100| 184.640 50.760 | 100| 187.878 x 44.490 ih 100| 132.880 < 41.960 100 | 138.880 43.120 C2 | 100| 128.880 & 40.400 100 | 119.200 37.280 (2) Descendants of Single Ex-conjugants. FI} 100] 193.000 & 50.840 | 56] 209.643 X 56.643 F2 | 100] 182.200 & 51.040 | 100] 199.960 & 50.120 (3) Descended each from 8 Equal Pairs. KI | 100} 133.680 X 39.400 | K2 | 100| 125.920 & 37.040 I00 | 125.000 * 42,520 (4) Descended from 10 Small Non-conjugants. ves 100| 131.400 < 42.000 | | | 100 | 128.840 & 41.360 (5) Older Lines, not from Culture J/. D III} 176.901 X 50.018 | 120| 187.033 XK 49.100 | g£ 100 | 124.440 X 35.920 | 140.800 39.640 Examination of this table shows that lines derived from different conjugating pairs or different ex-conjugants do differ from each other at the same periods in the life cycle, even though living under — 1908. | JENNINGS—HEREDITY IN PROTOZOA. 495 identical conditions. The differences are fully as marked as those _ found among diverse lines derived from individuals not conjugating and taken without reference to the period in the life cycle in which they happen to be. Besides this general result on our main problem, the following important facts are brought out by the table: 1. The six lines derived from the six different pairs (first six of the table) are clearly distinct. They show parallel differences in both sets of tests; the order of dimensions from largest to smallest is the same in both the first and the second measurements, though these are separated by at least fifteen generations. 2. The two lines, Fr and F2, derived from single ex-conjugants, are likewise distinct from each other. So far as the measurements go, Fz may possibly be the same as Ar, F2 as A2. 3. Certain different sets are likewise found in the other lots of the table. 4. The different sets fall into two very distinct groups, whose dimensions are separated by a wide interval. To the large group belong L2, Gr, Ar, A2, F1, F2 and D. To the small group belong the others. The greatest mean length of any set of the smaller group (140.800 microns) differs widely from the least mean length of any set of the larger group (176.901 microns). These two groups correspond in general to what we have heretofore called the “ aurelia form” and the “ caudatum form.” As there was no danger of confusing any lot of the larger group with any lot of the smaller one, the second measurements of the two groups were not made for the same day; the lots of the larger group were killed March 13, while those of the smaller group were not killed till March 109, as the table shows. This was done on acount of the great labor involved in select- ing, with capillary pipette, killing properly, and preserving, so many different sets on the same day. This difference of treatment of course does not alter the comparability of the different sets within a given group, which is all that we require. 5. How shall we decide which of the thirteen different sets form distinct lines? For this it will be best to take into consideration mainly the length, since we know from our earlier studies that little significance is to be attached to difference in breadth, owing to the extreme changes in that dimension with slight differences in food. 496 JENNINGS—HEREDITY IN PROTOZOA. [April 24, If any two sets differ in length in the same way at both measure- ments (taken many generations apart) and if the differences between - them are each time decidedly greater than the sum of the probable errors of the measurements of the two, then we can be assured that we are dealing with really differentiated sets. Now, examination of the extensive series of measurements in Tables X. and XVIII. shows that the probable error of the mean length never reaches two microns, even when the number of specimens is much smaller than in our present measurements, and when conditions are of the most varied character. It is practically certain that the probable error of the mean length would not amount to one micron in any of the compara- tively homogeneous sets with which we are here dealing. If, then, we require a difference of four microns between the mean lengths of the two sets, this difference to have the same sign (-+- or —) at both measurements, we shall be within safe limits. Applying this test, we find four lines clearly distinct in the larger or “ caudatum” group, while in the smaller or “ auwrelia” group we can be certain of but two distinct lines (represented best perhaps by J and C2). We have previously found three distinct lines in the aurelia group (c, g and i, Table XXIV.), so that all together we now have at least seven different lines of Paramecium, showing constant relative differences in length. It is probable that very exact tests would show the dis- tinctness of some other lines of Table XXV. The striking difference between adults of different races, under — varied conditions, is shown in Fig. 7. Here we have two adults, one belonging to our smallest race (7) ; the other to one of the large races. a Fic. 7. Extreme adult sizes from different pure lines of Paramecium. a, large individual from a large line. b, small individual from the small line + of Table XXIII., page 488. Both magnified 235 diameters. 1908. ] JENNINGS—HEREDITY IN PROTOZOA, 497 It is clear, then, that the question placed at the head of the present section is to be answered in the negative. The diverse lines of different size are not merely different stages in the life cycle. (c) Other Evidences of Permanent Differentiation in Size, Inde- pendent of the Life Cycle. The proof just given, that lines beginning with conjugarits are differentiated in size even in the same portion of the life cycle and under the same conditions, is conclusive. But it may be worth while to give briefly certain other evidences of the same thing. 1. First we have the fact that in a given culture the conjugauts themselves differ in size; this has already been shown by Pearl (1907). In a certain Culture IV., I found conjugants varying in dimensions from 148 X 44 to 260 X 60 microns. I have found (not in the same culture) conjugants with length as low as 100 microns. It is clear, therefore, that not all individuals are of the same size at conjugation. There is no reason to expect them to be so, there- fore, at other definite periods in the life cycle; as we have seen, they are not. Selection of small pairs gives small progeny ; of large pairs, large progeny. 2. In certain of my pure lines whose history was followed for a long time and whose dimensions were taken at intervals, conjugation occurred at times, but the dimensions at such times were not very different from the dimensions at other periods in the life history. Thus, in the earlier sections of this paper we have dealt with two pure lines, D and c; the former showed usually a mean length of about 180 microns, the latter a mean length of about 130 microns (see Table XVIII.). At a certain time an epidemic of conjugation arese in c. The mean dimensions were indeed higher than usual at that time, the mean length of the conjugants rising to 158.496° microns. But this does not by any means bring it up to the ordinary mean of D, and immediately after conjugation (in five days) the mean length of c fell back to 129.640 microns. Again, in the small race g, of Table XXIII., conjugation occurred in a number of cases; a typical pair measured but 110 microns in length. In other lines I have found for the conjugants means as high as 199.024 and as low 498 JENNINGS—HEREDITY IN PROTOZOA. [April 24, as 116.856, and these were correlated with corresponding measure- ments throughout the series. These facts, of course, do not show that the size may not change at the time of conjugation or before or after. What they do show is that any differences thus produced do not account for the perma- nent differentiations we have found among different lines. We may distinguish (1) differences in size due to growth; (2) those due to nutrition and other environmental conditions; (3) those due to different stages in the life cycle (as a rule not marked in comparison with the others); (4) inherent, hereditary differences in size, per- sisting when all other conditions are made the same. (d) Lines Intermediate Between the Two Main Groups. The Question of Species in Paramecium. As we have already noted, the seven differentiated lines which we have thus far distinguished fall into two main groups, separated by a wide interval. In Table XXV. we find one group with mean lengths varying from 119.200 to 140.800 microns, while in the other group the mean lengths vary from 176.901 to 220.560 microns. Between the two there is thus a gap of 36.101 microns in which none are found. Is this gap constant and characteristic, so that our two large groups are permanently differentiated? If so, we should have some real basis for the common distinction into two species, Para- mecium caudatum (larger) and Paramecium aurelia (smaller). The fact that we find in nature such cultures as that shown in Table I. (page 398), in which the individuals are distinctly separated into the two groups, seems to raise a presumption that the groups are natural ones, not due to accidents of selection. For a long time I found no pure lines that were intermediate between these groups. It is possible that this was partly due toa tendency to choose for breeding the largest and smallest specimens, rather than intermediate ones, since my purpose at first was to deter- mine whether there were any permanent differentiations at all; for this, marked differences were desirable. In the course of work on certain problems connected with con- jugation, I came in possession of a pure line, Nf2, descended from a single ex-conjugant. This, when cultivated in the usual hay infu- 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 499 sion, gave, under various different conditions, the following mean lengths in microns (each mean is based on measurements of 100 individuals) : 148.197, 151.920, 158.760, 153.320, 160.852, 156.482. It is evident that these means fall in the gap separating the “caudatum” group from the “aurelia” group. I therefore decided to cultivate these under identical conditions with a typical repre- sentative of each of the two main groups. For this purpose I chose D and ¢, the two lines longest cultivated, which I had used for the study of growth, environmental action, etc. (Tables X., XVIIL., etc.). Twenty-five specimens, each of the three lines, D, c and Nfa, were brought on May 1, with the precautions described on page 489, into the same quantity of the same hay infusion and allowed to mul- tiply till May 5. On that date a random sample of each was killed. Though the samples were large, extrinsic conditions prevented my measuring more than the numbers mentioned below; larger numbers would not have altered the results by more than one or two microns in any case. The mean dimensions of these three lines, cultivated under identical conditions, were D (31 specimens), 202.710 X 51.871 microns. Nf2 (33 specimens), 168.970 X 48.970 microns. ¢ (43 specimens), 126.605 X 44.930 microns. Thus, the dimensions of Nf2 lie almost precisely half way between those of D and ¢ (the dimensions exactly half way between would be 164.658 X 48.401). We have, therefore, in Nf2 an eighth pure line, intermediate between the “caudatum” and “aurelia” groups formed by the other seven. These two groups are then not sepa- rated by an unbridged gap. The other character which had been held to separate Paramecium caudatum from Paramecium qurelia was the presence of but a single micronucleus in the former, while the latter had two. Calkins (1906) showed that in the same pure line we sometimes have two micronuclei, sometimes but one, so that this is not sufficient ground for distinguishing two species. Though the present study has shown that differences in size among different lines are more permanent than the data available to Calkins had seemed to indicate, this does not give any better basis for distinguishing two species, since we 500 JENNINGS—HEREDITY IN PROTOZOA. [April 24, have been able to isolate, not merely two permanently differentiated lines, but eight. Of course, it would require merely more extensive and intensive work to isolate others; doubtless the number to be isolated would depend only on the accuracy of the methods used. To my great regret, I was unable to take the steps necessary to determine the number of micronuclei in the various pure lines with | which I worked. The animals multiply so rapidly that with several _ lines in progress it is quite impossible even to keep up with the data for size alone; probably half my experiments were lost on this account, after much work had been spent on them. It was then out of the question to carry on at the same time the staining processes necessary to determine with certainty the number of micronuclei. For work of the kind presented in this paper, a syndicate of investi- gators is needed for keeping track of the various important aspects of the matter. In the case of two of my lines the number of micro- nuclei was determined; D (larger) had one; c (smaller) had two. I may be permitted to add to the precise data thus far given a personal impression or surmise. Though, as I have shown, inter- mediate lines occur, I believe it will be found that most Paramecia can be placed in one of the two groups that we have called “ cau- datum” and “ aurelia.” In other words, if my impression is correct, most lines will have a mean length either below 145 microns or above 170 microns; rarely will lines be found whose mean falls between these values. Such at least has been my experience in a large amount of work. Furthermore, I am inclined to believe that those belonging to the smaller group (mean length below 145 microns) will be found to have as a rule two micronuclei; those belonging to the large group but one micronucleus. This matter is worthy of special examination. (e) Do the Diverse Lines Differ in Other Respects Besides Dimensions? In the investigations above set forth the dimensions, and espe- cially length, were made the basis of study, simply because they were the characters most readily examined. Most other characteristics are not easily handled in so minute and relatively undifferentiated an animal as Paramecium. But there is, of course, no reason to 1908. | JENNINGS—HEREDITY IN PROTOZOA, / 501 suppose that the relations we have brought out are limited to length alone. Probably other differentiated pure lines could be distin- guished on the basis of other characteristics. The only other characteristic on which our data might give results is that of form, as distinguished from size. Are some races broader, some narrower, in proportion to the length? We may first examine this question with reference to the two main groups into which most of our lines fall. Is there any general diffetence in the proportion of breadth to length when we compdre the larger races (“ caudatum group”) with the smaller ones (“ aurelia group”)? The experiments whose results are summarized in Table XXV., page 494, give us data for a number of different lines of both groups, cultivated under the same conditions. We may, therefore, determine the proportion of breadth to length in these. The more accurate way of doing this would be by means of the formula given on page 399. This, however, would involve much computation not made for other purposes; and we may reach very nearly the same results by simply dividing the mean breadth by the mean length. If the differences between the different races are not sufficient to show clearly under this treatment, they are doubtful and inconsequential. The following table gives the ratio of mean breadth to mean length in the different lines represented in Table XXV.; the lines are arranged according to relative size, so as to exhibit any differences between the large and small groups. The table shows that the ratio of breadth to length is almost uniformly greater in the small or aurelia group than in the larger. The lowest ratios of the aurelia group are, indeed, a little below the highest of the caudatum group, but the difference between the groups as a whole is unmistakable. The first column of the table is the most satisfactory in this respect, since both sets were killed at the same time. In the second column the difference between the ratios for the two groups is still more decided, but environmental differences may play some part in this case. The average ratio for the cau- datum group is, from the first column 27.473 per cent.; from the second 25.679 per cent. For the aurelia group the averages are: first column 30.441 per cent.; second column 31.319 per cent. The 502 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE XXVI. Ratio of Mean Breadth to Mean Length in the Lines and Races of Table XXV., page 494, Cultivated under Identical Conditions. xz. Caudatum Group. February 26. March 13. Per Cent. Per Cent, L2 29.482 27.185 GI 26.018 24.744 AI 26.782 25.810 Fi 26.342 27.019 A2 27.491 23.680 F2 27.921 25.005 D 28.275 26.252 2. Aurelia Group. February 26. March 1x9. Per Cent, Per Cent. Ki 29.473 I 31.577 31.048 H 31.967 32.102 C2 31.347 31.275 K2 29.416 34.016 g 28.865 28.153 general average for the caudatum group is 26.576 per cent.; for the aurelia group 30.840 per cent. In Table XXIV., page 491, we have data for certain other mem- bers of the two groups when cultivated under similar conditions. If we determine the ratio of mean breadth to mean length for this table, the results are not so clear as in the cases we have just con- sidered. They are given in Table XXVII. Taste XXVII. Ratio of Mean Breadth to Mean Length for the Races of Table XXIV., page 491. r Caudatum Group. Pporegey. 5: he A Pe Cae E 31 245 - 158 26.458 27.615 26.010 ? FE 5.651 { 28.723 26.893 Average 28.170 26.964 26.675 2. Aurelia Group. c big 26.306 20.5 g { 30.853 28.298 eee 31.852 Average 29.118 28.849 In this table the averages for the aurelia group are again higher throughout than for the caudatum group. But the highest ratio is given by one of the caudatum group, and the line c of the aurelia 1908. ] JENNINGS—HEREDITY IN PROTOZOA, 503 group gives in both cases a low ratio. But taking the averages, in connection with those of Table XXVI., it is clear that the smaller races are as a rule slightly broader in proportion to the length than are the larger races. Turning now to the question whether there are differences in the proportion of breadth to length in different races of the same group, we have full data only for the lines g and i, as given in Table XXIII., page 488. Beginning with the data for November 23 (since before that date the number of individuals is small), we can make determi- nations for seven different dates of the ratio of mean breadth to mean length, the two sets being on each date as nearly as possible under identical conditions. Taste XXVIII. Ratio of Mean Breadth to Mean Length for g and i (Table XXIII.). November November December December December January February 23. Per 26. Per 7, Per 16. Per 30. Per 2. Per 5. Per Cent. Cent. Cent. Cent. Cent. Cent. Cent. g 27.011 28.238 34.001 30.370 27.797 27.686 30.853 1 34.291 28.325 34.655 30.159 25.430 24.747 29.386 Thus, in the first three determinations the ratio was greatest in the line 7; in the last four it was greatest in the line g. Evidently there is no constant difference in proportions between these two lines. For other lines our data are not sufficient to test this matter. Our only positive result on this point then is that the smaller races are as a rule proportionately broader than the larger ones. 2. RESULTS OF SELECTION WITHIN PuRE LINEs. We have seen that an ordinary “wild” culture of Paramecium contains many lines or races, which are differentiated in size. By selection it is possible to isolate these diverse lines; so that in this way we can obtain cultures in which the mean size is large or small, or intermediate, as we prefer. In this case selection, of course, acts by isolating lines that already exist, and allowing them to propagate unmixed. How do these diverse lines arise? Can we obtain them by selec- tion within the limits of a single line? If from among the progeny of a single individual we select the larger and the smaller specimens, 504 JENNINGS—HEREDITY IN PROTOZOA. [April 24, will we obtain two diverse lines, one showing a greater mean size than the other? As we have already seen, our first attempts to do this failed. But these first experiments were made before our study of growth and environmental effects, so that the basis of selection was wrong. The smaller specimens selected were as a rule the younger ones; they grew to full size, then, of course, produced progeny of the same size as other adults. , After the thorough study of growth, it appeared possible that a more adequate method of selection might be found. The propor- tions of the young differ from those of the adult (as our account has shown), so that after long practice one comes to recognize the young specimens with some accuracy. It appeared worth while, therefore, to attempt to select larger and smaller adults for further propagation. (a) Differences Due to Environmental Action Not Inherited. It is, of course, easy to obtain within a pure line adults ot differ- ent size, by subjecting them to different environments. An analysis of our section on the effects of the environment shows that as a rule these are not inherited. Thus, if we examine Table XVIII. (page 460), we find that the same set that gave on July 17 a mean length of 184.100 microns (row 7) gave one week later, under different conditions, a mean of 146.108 microns; one day later 163.932 microns ; one week later 174.400 microns; two days later 191.360 microns. The breadth changed even more, and the extremes of size in a given culture showed corresponding changes. There was no difficulty in changing the dimensions back and forth in the most varied ways. The entire Table XVIII. is an illustration of the general lack of continued inheritance of environmental effects. Many experiments directed precisely on this point gave the same results. When, for example, the small specimens of row 8 (Table XVIII.) were cultivated under the same conditions as large speci- mens from row 9, the resulting cultures were soon indistinguishable. Thus, it is clear that such environmental action as is summarized in Table XVIII. is not as a rule inherited. But I wish to point out and emphasize certain facts regarding the experiments on the action of the environment. (1) In all the experiments thus far tried, the 1908. | JENNINGS—HEREDITY IN PROTOZOA. 505 differential action of the diverse environments lasted but a short time. (2) The experiments were directed toward determining whether the differences produced were permanently inherited. Crit- ical investigations have not yet been made to determine whether the environmental effects may not persist for one or a few generations after transference to the new fluid; nor whether long continued action of a certain environment may not produce more lasting results than brief action. To these points I hope to devote special and extended investiga- tions. The purpose in the present paper is to show on this matter the main general result; this unquestionably is that environmental action is not as a rule inherited in any lasting way. (b) Selection from Among Differing Individuals in the Same Environment. Besides the differences among individuals under different envir- onments, we likewise find differences among individuals of the same pure line in the same culture, as_a glance at the tables of the appendix will show. What will be the effect of selecting for breeding larger and smaller specimens from such a culture, avoiding, so far as pos- sible, different stages of growth? In order to make the selections properly, certain things must be considered. (1) It is well to bring the culture into as stable a con- dition as possible—a condition where there is little or no multipli- cation—in order that we may not be confused by different stages in growth. (2) It must be remembered that, so long as conjugation does not occur, the same results that selection would produce are brought about in the ordinary course of events, save that the large and small specimens remain mixed. That is, if there is congenital variation, producing large and small individuals, this must occur in the same way whether the different sizes are isolated or not: The progeny of every individual forms a “ pure line,” quite unmixed with any other, so long as no conjugation occurs. If, then, by variation a large individual a and a small one b are produced, and these differ- ences are inherited, then later we shall find a mixture of two strains instead of a single strain. We should then expect the progeny of a PROC, AMER. PHIL. SOC, XLVII. I90 GG, PRINTED JANUARY 12, I909. 506 JENNINGS—HEREDITY IN PROTOZOA. [April z4, single individual to show more and more variation as the strain became older; it would break into several or many strains, which would, however, remain intermingled. Therefore, the best method of procedure will be to take an old strain, which, derived from a single individual, has for a long time been multiplying freely without conjugation. From this the largest and the smallest individuals should be separated and allowed to propagate under identical conditions. If hereditary variations in size have occurred, we should in this way reach the same result as by actual selection and isolation through many generations. Physio- logical isolation has been as complete as would be experimental isolation. A race fulfilling these conditions we have in the pure line derived from the individual D, on which most of the work described in the first parts of this paper was done. On January 19, 1908, large cultures of D had been multiplying without conjugation since April 12, 1907, a period of about nine months. During this time about 250 generations must have been produced; these had remained physio- logically isolated. The superfluous individuals had been removed by periodic “ catastrophic” destruction; the greater part of the culture was thrown out, and a remnant saved, without selection, for a new culture. On January 19, 1908, I took from the large stock culture of D (1) the ten largest individuals that I could find; (2) the ten smallest individuals I could find. They were separated in two watch-glasses and. kept under identical conditions. The difference between the two sets was very marked; the smaller lot were certainly not more than two-thirds the length of the larger, and they were very slender, while the large ones were both long and broad. It was clear that both sets were adults. It was found that the smaller lot multiplied much less rapidly than the large lot, and some of the small ones died. By January 30 there were but twenty of the small lot, while a very large number had arisen from the large lot. On this date the culture fluid was changed and but fifty of the larger lot retained. The small lot con- tinued to multiply very slowly. It is clear that the small specimens 1908. ] JENNINGS—HEREDITY IN PROTOZOA, 507 are weak, sickly ones, and the physiological difference persists at least for some generations (a matter for further study). On February 5 about half of each lot was killed and measured. This gave 57 specimens from the larger lot, 19 from the smaller. The mean dimensions were, for the larger lot, 169.754 46.877 microns; for the smaller lot, 169.895 X 43.579 microns. Thus the two were practically identical; one could not expect a closer approximation in two identical lots kept separate for seventeen days. The slight difference in breadth is only what we might expect when we consider the extreme sensitiveness of that dimension to faint environmental differences. The most striking differences that we can find as a result of physiological isolation for 250 generations have equalized themselves in a short time, when we got both sets to multiplying freely under the same conditions. It seems hardly worth while to continue this series, since the two sets have now become equalized. However, they were continued for some time, and samples of 100 each were measured on February 15 and February 27. In these two measurements we find certain differences between the two sets, but these are in opposite directions in the two cases. The means are as follows: February 15. February 27. Large D 180.240 * 46.880 175.300 X 47.100 Small D 173.240 X 49.760 193.680 XX 52.320 Evidently slight environmental differences between the two cultures had crept in. It is clear that the two sets show no constant differ-_ ences, such, for example, as we find between the two lines, g and 1, in Table XXIII., page 488. Another set of experiments dealt with the two differentiated lines, g andi. ‘The line g consists of individuals that are constantly larger than those of the line 1, when the two are under the same conditions (see Table XXIII., p. 488). The experiments consisted in an attempt to separate these races still farther by propagating continually from the largest specimens of g and from the smallest specimens of 1. Thus, if selection is effective, g must become larger, asmaller. The length was the dimension mainly attended to in these selections. On November 23, 1907, the mean size for g was 129.333 X 34.933 508 JENNINGS—HEREDITY IN PROTOZOA. [April 24, microns; for 7 it was 88.268 X 30.268. On this date I placed in separate watch-glasses the ten largest specimens of g and the ten smallest specimens of i, keeping them under the same conditions. On November 29 I again selected from the progeny of these the ten largest g and the ten smallest 7, destroying the others. On December 7 the same selection was repeated; the remainder of each lot was killed and measured. The mean measurements were g, 120.590 X 41.115 microns. i, 98.709 X 34.208 microns. Thus, in spite of the fact that for at least fourteen generations we have selected for propagation the largest of g and the smallest of t, g has become smaller and i has become larger! The results of selection, if there are any, quite disappear in comparison with the effects of slight environmental differences. In spite of this discouraging result, the experiment was -con- tinued. On December 16 I selected the five largest g and the five smallest 7 and again measured the rest of each. The results were J, 127.059 X 38.588 microns. i, 98.608 X 29.739 microns. Thus, i retains the same length, while g has increased, but has not regained the length it had at the beginning of the experiment. On December 25 the five largest g and the five smallest 1 were again selected for propagation. On December 30, thirty-seven days okies the beginning of the experiment, I again measured all but the five largest of g ani the five smallest of 7. The results are J, 112.600 X 30.300 microns. 1, 86.756 X 22.062 microns. Bs) Thus, 7 has decreased as compared with its original length, while g, which was selected for increase of size, has decreased a great deal more! The decrease in length of i is less than two microns; the decrease in g is more than sixteen microns! And this is the result of five selections, taking for g the largest, for i the smallest, specimens produced in the course of at least thirty generations !§ *The number of specimens on which the measurements are based will be found in Table XXIII., page 488, which includes, for another purpose, the measurements from these experiments. 1908.] JENNINGS—HEREDITY IN PROTOZOA, 509 Evidently, selection is having no effect that can be detected. The fluctuations in the two sets are precisely what would be expected from unavoidable changes in conditions of nutrition; they show no relation to selection. " ; : Later another experiment in selection was tried with these same races, g andi. On January 19 I selected from a large culture that had been multiplying freely for a month (1) the ten largest speci- mens of g that I could find; (2) the ten smallest specimens of g; (3) the ten largest specimens of7; (4) the ten smallest specimens of 1. These were allowed to multiply under identical conditions till February 5. Then a sample of fifty of each was measured. The results are as follows: Large g, 114.720 X 33.920 microns.® Small g, 116.912 X 36.070 microns. Large 1, 92.000 X 26.960 microns. Small i, 93.583 X 27.500 microns. The difference between the two sets of each is slight and without significance, but such as is found is in favor of the progeny of the smaller specimens in each case. Evidently, we are not making a start with any effect of selection, and it is useless to continue the experiment. Many other attempts were made to break a pure line by selection into several strains; on this point an immense amount of work was directed. But in most cases the difference between the two sets became equalized almost at once, so that the experiments were not carried farther. As soon as two unequal sets become quite equalized, there is little opportunity for further selection. In the experiments described above, though their futility seemed evident from the first results, the work was continued for many generations, in order that failure might not be due to lack of perseverance. One other set of experiments deserves to be described, because in these the basis for selection was changed. Among the progeny of a certain individual Nf2 conjugation occurred. The conjugants varied in size. This offered an opportunity to make a selection ®*These measurements are found, for another purpose, in Table XXIV.,, page 491. 510 JENNINGS—HEREDITY IN PROTOZOA. [April 24, based on specimens that were evidently adults; possible confusion due to growth differences could be avoided. On March 31 I killed and measured all but the largest and smallest pairs of conjugants ; the length was found to vary from 124 to 148 microns. The smallest and largest pairs were reserved for propagating; the former, of course, measured not more than 124 microns, the latter not less than 148 microns. These were allowed to multiply separately, but under the same conditions, till April Io. On April 10 I measured a random sample of 100 specimens of the progeny of each of these pairs. The results are as follows: Larger pair, 151.920 X 43.840 microns. Smaller pair, 158.760 X 38.120 microns. . Thus, the difference in size, whatever its cause, does not corre- spond to the difference between the ancestors; selection for size has had no evident effect. Another experiment on the progeny of Nf2 consisted in com- paring the descendants of a single small conjugant with those of several large non-conjugants. Details of this and similar experi- ments will be reserved for our paper on the relation of conjugation to variation and heredity. But since it has a certain bearing on our present problem, the results may be given here. At the same time with the cultures last described (on March 31), I isolated ten of the largest non-conjugant progeny of the same individual Nf2. A sample of thirty-four of these had given a mean length of 147.412 microns, so that this may be taken as the mean length of these ten specimens. With the progeny of these was com- pared the progeny of the smaller pair mentioned in the preceding experiment. As we have seen, this pair measured not more than 124 microns in length. The greatest pains were taken to cultivate the two sets under identical conditions. On April 20 I killed a saniple of 108 of each. The mean measurements were as follows: Progeny of small pair (124 microns) — 160.852 X 42.036 microns. Progeny of ten large (147 microns) — 156.482 X 43.815 microns. Thus, again, there is no correspondence between the differences in size of the parents and those of the progeny. The determining factor in the size is the fact that both sets belong to the same pure 1908. | JENNINGS—HEREDITY IN PROTOZOA. 511 ~ line; the variation of the parents from the type of the pure line has no effect. The difference in the figures above is either purely statis- tical in character or means a faint variation in the culture fluid. (c) Summary on Selection within Pure Lines. Thus, we come uniformly to the result in all our experiments, that selection has no effect within a pure line; the size is determined by the line to which the animals belong, and individual variations among the parents have no effect on the progeny. But for our results with different lines, it might be maintained that the reason why we get no constant differences between the progeny of different individuals of the same line is because the effects of environment are so much greater than the effects of selec- tion that the latter are covered up and obscured. But as soon ‘as we are dealing with lines that are really different (though by but a small amount) we have no such difficulty ; the different lines retain their relative sizes in spite of environmental action. This is clearly shown in Tables XXIII. and XXV., pages 488 and 494. The significance of these results will be dealt with in the next section. VI. SUMMARY AND DISCUSSION. I. RESUME OF THE INVESTIGATIONS. The present paper is an experimental study of the factors involved in variation and inheritance of size in the infusorian Paramecium, in the period when reproduction is taking place by fission, without conjugation. 1. The first question proposed is whether the differences in size among different individuals of a culture are inherited. The pre- liminary study showed that in a typical culture there were two permanently differentiated groups of large and small individuals, respectively, corresponding to what had been described as the two species, Paramecium caudatum and Paramecium aurelia. But when a culture was produced from a single individual of either of these groups, forming thus a “ pure line,” it was found that though the different individuals of the single pure line differed much in size, 512 JENNINGS—HEREDITY IN PROTOZOA. [April 24, these differences were not inherited. Large and small specimens of ~ a single pure line produced progeny of the same mean size. _ 2. The next question then was: What are the causes and the nature of the variations in size among the different individuals of a culture of Paramecium? Even in a pure line the indi- viduals differ greatly. The “ polygon of variation” of a given cul- ture was looked upon as a mass of problems for analysis. What determines the position which any given individual holds in such a polygon, or in a correlation table? And why do different lots of Paramecia differ in mean dimensions; in the amount of variability; in proportions, and in the correlation between length and breadth? The analysis of the factors in variation led to a detailed study of (1) growth, (2) the effect of the environment; (3) inherited differences in size. To these three matters the three main divisions of the paper are devoted. To one or the other of these three cate- gories most of the variations in size were found to belong. A fourth category, consisting of variations connected with conjugation, is reserved for consideration in a later paper. 3. A large share of the differences in size to be observed in a given culture are differences in growth. In study of variation in protozoa it is as necessary to take growth into consideration as it is in the study of higher animals; the part played by it is fully as great in the protozoa as elsewhere. The paper gives a detailed study of growth, based on the measurements of I,500 specimens of various known ages, in comparison with large numbers of “random sam- ples.” In this way a curve of growth was plotted (Diagram 5, page 449) ; this curve resembles essentially the curves of growth of higher animals, as the rat, or man. In different parts of this curve of growth individuals show different lengths, different breadths, and, of course, different proportions of breadth to length. A flourishing culture contains individuals in all stages of growth; so that this affects largely the mean dimensions, the Observed variations, and the correlations between length and breadth. The precise effects of growth on each of these matters are dealt with in detail in the paper ; they will be summarized in later paragraphs. A summarized account of growth and its effects is found in the body of the paper, pages 447 to 458; the constants for dimensions and variation in dif- S508.) JENNINGS—HEREDITY IN PROTOZOA. 513 ferent stages of growth are brought together in Table X., page 428. 4. Environmental conditions were found to play a very large part in determining dimensions, variations and correlation in Para- mecium. Conditions of nutrition were found to be particularly effective. By changes in nutrition the mean length of a given culture could be changed in a week from 146 microns to 191 microns; the breadth from 31 to 54 microns; in twenty-four hours the coefficient of variability for length was thus changed from 7.003 to 12.767, for breadth from 12.473 to 28.879; the coefficient of correlation from 3906 to .8463. Changes of the most varied sort could be produced and reversed with the greatest ease in short periods; many examples of this are summarized in Table XVIII., page 460. Within a given culture at a given time many of the differences between individuals are due to slight environmental, differences in different regions. The breadth is more sensitive’ to environmental changes than the length; to such an extent is this true that it is difficult to use the, breadth dimensions for accurate study of any other factors. A sum- mary on the effects of the environment on dimensions, proportions, variation and correlation is found on pages 476 to 484. 5. After the study of growth and environmental action, an inves- tigation was made of the internal factors in dimensions and variation ; of the inheritance of size. Are all the observed differences between the individuals of a culture mere matters of growth and environ- ment? Or may we find different races or lines that retain their relative’ sizes even in the same stage of growth and in the same environment? | A thorough experimental study showed that a given “wild” culture usually contains many different lines or races, which maintain their relative sizes throughout all sorts of changing conditions. Eight of these differing pure lines were isolated and propagated ; these varied in mean length from a little less than 100 to a little more than 200 microns (see Tables XXIII. and XXV.). Other lines could unquestionably be distinguished by sufficiently accurate experimentation. These different lines fall usually into two main groups, one group having a mean length greater than 170 microns, the other having a mean length below 140 microns. These two groups correspond to 514 -JENNINGS—HEREDITY IN PROTOZOA. [April 24, the distinction that has been made between two species, the larger ones representing the supposed species caudatum, the smaller ones aurelia. But a line or race was found with mean length lying mid- way between these groups, at about 150 to 160 microns. The smaller or aurelia lines were found to be, under the same conditions, as a rule a little broader in proportion to the length than the larger or caudatum lines. But the difference is slight and the two sets overlap extensively in this matter; slight differences in environment quite obscure the difference in proportions. The differences among the different lines were found not to be due to different periods of the life cycle. By beginning with con- jugating pairs of different sizes, distinct pure lines were as readily isolated as by beginning anywhere else in the cycle. 6. After becoming thoroughly familiar with differences due to growth, to environment, and to divergent ancestry, a further attempt was made to change by selection the characteristics of pure lines, or to break such lines into strains of differing size. In spite of much work directed on this point, it was found that selection within a pure line was quite without effect. Large individuals of the line produce progeny of the same mean size as do the small individuals. To this matter we return in later paragraphs. 2. DETERMINING FACTORS FOR DIMENSIONS, VARIATIONS AND CORRELATIONS. Based on the analysis of the factors in variation above set forth, a summary can be given of the various determining causes of the different dimensions, the proportions, the amount of variation and the correlations observed in samples of different cultures of Para- mecium. We may take as an example such a sample as is shown in Table LXI. (appendi&k) from a “ wild” culture. 1. The various different lengths depend upon the following factors: (a) The collection embraces a number of different races or lines, having different lengths even when all conditions are the same. We have seen that different lengths varying from less than 100 to more than 200 microns may be included as a result of this fact. The mean length may not represent any of these races (this is the case in Table I.). 1908.] JENNINGS—HEREDITY IN PROTOZOA. 515 (b) The collection includes various growth stages of each of the lines represented. The youngest stages of each line are little more than half the lengths of the adults; all intermediate stages may be present, and the adults themselves shorten again as they approach fission. A very wide range of variation in length may be brought about by these growth stages, all within the limits of a single pure line or race. Of course when many different lines are present, an immense number of combinations are thus produced. (c) The collection includes individuals of the various races that have lived under slight or considerable differences in environment, particularly in the matter of nutrition. Those that have been able to get more food will be much larger and will multiply more fre- quently (thus giving more young) than those that get less. Even slight environmental differences make decided differences in dimen- sions. While the environment shows its effects most strongly on comparison of different cultures, even within the same culture, and when all the individuals are of one race and of approximately the same age, there are marked differences due to this cause. This is shown, for example, in Table XLI. (appendix) ; here variations in length from 140 to 200 microns must be considered environmental effects. A few drops of water form a varied microcosm to the infusoria. When diverse pure lines, diverse growth stages, and diverse environmental conditions are found in a culture (as is usually the case), of course, the number of different sizes and forms due to the varied combinations of all these factors are very great. The same sizes may, of course, be produced in different ways ; two diverse lines in different stages of growth or in different environments, or in some combination of the two, may produce forms outwardly iden- tical. The actual variety, as defined by the physiological conditions, is therefore much greater than the measurements show, for the latter throw together heterogeneous conibinations. Combinations of all the three factors inducing diversity might give us in a single collection individuals varying in length from 50 microns to 332 microns. While these are the extremes given by our data, presumably the actual extremes would be still more divergent. (d) In different collections the observed mean lengths depend upon the three different sets of factors just mentioned. The inclu- 5156 JENNINGS—HEREDITY IN PROTOZOA. [April 24, sion of different lines or races, even if conditions of growth and environment are essentially the same, may give us, as we have seen, mean lengths of somewhat less than 100, or somewhat more than 200 microns, or any intermediate length. Different stages in growth may give us, in the same line and in the same environment, means differing to such an extent that one is nearly twice the other, or any intermediate condition. The absolute extreme values will, of course, depend upon the race employed; in the line 7 the variation of mean length caused by growth might be from about 50 to about 100 microns; in D it was from about 100 to about 200 microns; in L it would be from about 117 to 234 microns. Different environmental conditions give us, within the same lines, mean lengths differing to suth an extent that the greater is 25 to 30 per cent. more than the less (lines c and D). In different “ wild” cultures we shall have different combinations of all these factors, resulting in extreme diversities in different cases. Fig. 7 shows two extreme sizes drawn to the same scale (page 496). 2. The various different breadths depend upon the same factors as the different lengths. There are certain differences, however. As compared with length, the breadth is affected much less by growth; about the same (though a trifle less) by diversity of race; and much more by environmental differences. Environmental dif- ferences produced within the races D and ¢ such differences in mean breadth that the greater was about twice the less. 3. The observed variation, as measured by the coefficient of variation, of course, depends upon the three sets of factors enumer- ated above as affecting the length and breadth. If a collection consisted of several different lines or races, all in the same condition as regards growth and environmental conditions, this would, of course, give us a considerable coefficient of variation. For example, if a collection consisted of ten infividuals each of all the different lines represented in Table XXVI., page 502, and if all of each set of ten had the mean dimensions for its line (thus excluding differences - due to growth and environment within the lines), the coefficient of variation when computed in the same way as for the actual collections given in the text is found to be for length 19.689; for breadth 15.679. If a collection consists of individuals all belonging to the same 1908.] JENNINGS—HEREDITY IN PROTOZOA, 517 / line or race, and in the same environment, then the coefficient of variation depends largely upon the stages of growth it contains. By taking specimens nearly in the same stage of growth we were able to reduce the coefficient of variation in length in some cases to 4.521, in breadth to 6.976, while by taking collections including various ages, under similar conditions, coefficients were found as high as 13.729 for length and 13.292 for breadth (Table X.). The most carefully selected lots contain specimens differing a certain amount in age, otherwise the coefficient of variation could be still further reduced in this way. Specimens beginning fission or undergoing conjugation include few growth stages, hence they show a low coeffi- cient of variation. The coefficient for those beginning fission is less than for conjugants (see page 453). The coefficient of variation for a given line is tremendously affected by environmental conditions. Thus, we see this coefficient changed in twenty-four hours, by a change in environment, from 7.003 to 12.767 for length; from 12.473 to 28.879 for breadth. Different environments give us all sorts of values between such extremes. It is evident that no particular coefficient of variation can be considered characteristic of Paramecium, or of any line of Para- mecium; certainly not unless the conditions as to growth, envir- onment, etc., are very precisely defined. We have seen that the variations found among different individuals of the same pure line do not show themselves to be heritable. This, along with all the rest of the evidence, indicates that if all conditions of growth and environment were made identical throughout a sample of Paramecia belonging to a pure line, the coefficient of variation would be very near to zero. In other words, all the variations that we have been able to detect with certainty in a pure line are due to growth and environment. Presumably other variations (congenital and heredi- tary) must occur at times, but they appear to be so rare that it is difficult to detect them and they would have little effect on the coefficient of variation. By properly varying the conditions, we may get in a pure line all coefficients of variation in length, from a limit near zero up to 20 or more. . 4. The ratio of breadth to length (serving to partly define the 518 JENNINGS—HEREDITY IN PROTOZOA. [April 24, form of the body), of course, varies in dependence upon all the three sets of factors with which we have dealt—difference of race, growth and environmental conditions. The smaller races are found to show, under the same conditions, a slightly greater ratio of breadth to length (see Table XXVI.). Within the same race different stages of growth show different ratios ; in general, the proportion of breadth to length is greatest in the young, and gradually decreases with age; it increases again very rapidly in preparation for fission. Environ- mental agents affect in most marked and varied ways the proportion of breadth to length; this is connected with the fact that such agents act more upon the breadth than upon the length. A detailed sum- mary of the different effects of the environment on the proportion of breadth to length is found on pages 478 and 479. The most im- portant general relation is, that increase of nutriment increases the proportional breadth; decrease of nutriment produces the opposite effect. Any agent which suddenly increases the breadth likewise, as a rule, increases the ratio of breadth to length. 5. The coefficient of correlation between length and breadth is the measure of the accuracy with which breadth and length vary proportionately. If the proportion of breadth to length is the same in all individuals of a collection, then the coefficient of correlation of that collection is 1.000.1° Since, as we have just seen, the pro- portion of breadth to length is altered by many factors, it follows that all these factors modify the correlation, tending to reduce it below 1.000. The correlation is affected by all the three categories of factors that affect the dimensions in essentially the following ways: (a) The inclusion of different races in a collection, particularly if some of the smaller and some of the larger races occur, makes the correlation less than 1.000, because the proportion of breadth to length is greater in the smaller races. The reduction in correlation produced by this alone is very slight. If we make a collection by *It is perhaps not necessary to point out that the “coefficient of correla- tion” is descriptive; it shows the observed condition in a given set of meas- urements. The cause of this condition is a matter to be determined. Corre- lation is often conceived physiologically as an underlying something that binds two things together, so that they must change correspondingly. The descriptive correlation of the statistician may be the resultant of many factors. 1908.] JENNINGS—HEREDITY IN PROTOZOA, 519 throwing together ten each of the different lines of Table XXV. (page 494), giving the individuals of each line the mean dimensions of its line (thus nearly excluding variations due to growth and environment), then calculate the coefficient of correlation in the same way as for our other collections, we find it to have the high value of .9735. (b) The inclusion of different stages of growth in a collection reduces the correlation below 1.000, since different growth stages have different ratios of breadth to length. A detailed summary of the effects of growth on correlation is found on pages 455 to 457; here we can notice only the main points. In the earliest stages of growth the length is increasing while the breadth is decreasing; hence if we take a collection including various stages within this period, the correlation between length and breadth becomes negative ; it may fall to a value of —.3138 (see Table X.). The inclusion of various early stages in a collection of adults decreases the positive correlation shown by the adults. In later growth, length and breadth increase together; the inclusion of various stages at this period has little effect on the correlation; it does, however, tend to reduce it slightly, since length and breadth do not increase at the same ratio. In old specimens, beginning fission, the length decreases while the breadth increases; a collection including different stages in this process tends again to give negative correlation, or to reduce the positive correlation due to other causes. In a collection from the same ptire line, in which all specimens are in the same stage of growth, the correlation between length and breadth is high; this would be true no matter what stage of growth is the one represented. Random samples from any culture usually contain many stages of growth; this lowers the correlation between length and breadth. (c) Environmental differences, like growth, affect length and breadth differently or in different proportions; if individuals thus diversely affected are included in a sample, this tends to decrease the correlation between length and breadth. A detailed analysis of the many and important effects of environmental action on the corre- lation will be found on pages 481 to 484; here, again, we can but summarize the important points. 1. Certain environmental agents increase the breadth while decreas- 520 JENNINGS—HEREDITY IN PROTOZOA. [April 24, ing the length. Inclusion of different stages of this process in a sample reduces the correlation ; it may make it zero or negative. 2. Most environmental agents change the breadth more than the length, even when both are changed in the same direction. The inclu- sion of different stages then reduces correlation. 3. Samples in which some of the specimens are well-fed and’ plump, others ill-fed and thin, of course, show low correlation, since the ratio of breadth to length is not uniform. ‘This is usually the case in cultures where food is scarce. 4. Addition of abundant nutriment causes the thin specimens to increase in breadth, by taking food, while the plump ones change little. As a result the proportion of breadth to length becomes nearly uniform throughout the lot; the correlation is therefore increased. As a rule, any agent which increases the mean breadth likewise (for the reason just set forth) increases the correlation between breadth and length. Decrease of nutriment, for the converse reason, decreases the correlation. 5. Any agent that causes rapid multiplication decreases the cor- relation between length and breadth for the period of multiplication. This is owing to the inclusion in the collection of many stages of growth, showing different proportions of length to breadth. . 6. Slight differences in one dimension may be produced without corresponding differences in the other, so that in a collection varying little in length the correlation may be low. But considerable changes in one dimension are usually accompanied by corresponding changes in the other. Hence, when two groups of differing lengths are thrown together, the correlation may become higher than in either one taken separately (for example, see page 437). In any ordinary sample of Paramecium all these varied factors are at work in determining the observed correlation. It is clear that no particular coefficient of correlation can be considered character- istic for Paramecium or for any particular race of Paramecium, for by various combinations of these factors we may get any coefficient — of correlation ranging from a pronounced negative value upward through zero to a high positive value. In Tables X. and XVIII. we 1908.] JENNINGS—HEREDITY IN PROTOZOA. 521 see varied collections showing extremes of value for the coefficient of correlation, from — .3138 to + .8500." 3. RESULTS ON VARIATION, INHERITANCE AND THE EFFECTS OF SELECTION. Our general results with regard to variation, inheritance and the effects of selection are then as follows: In a given “pure line” (progeny of a single individual) all detectible variations are due to growth and environmental action, and are not inherited. Large and small representatives of the pure line produce progeny of the same mean size. The mean size is therefore strictly hereditary throughout the pure line, and it depends, not on the accidental individual dimensions of the particular pro- genitor, but on the fundamental characteristics of the pure line in question. In nature we find many pure lines differing in their characteristic mean dimensions. Our results with the infusorian Paramecium are, then, similar to those reached recently by certain other investigators working with pure lines of other organisms. Johannsen (1903) showed that in beans and in barley many pure lines, slightly differentiated from each other, exist in nature, but that selection within a pure line has no effect upon its characteristics. These plants are self-fertilized, so that there is no intermingling of different lines. Hanel (1907) has recently found the same state of affairs in Hydra when multi- plying by budding. Certain lines tend to have a higher mean number of tentacles, others a lower mean number. But within a given line selection of parents with more or fewer tentacles has no effect on the progeny; selection has no effect within the pure line. It is doubtless too early to draw any very positive conclusions from these facts. While the results with Paramecium seem clear, I intend to test them further in every way possible. It is pos- sible that selection may be made on some other basis, with a better _™This fact of course does not render the study of the coefficient of correlation valueless. Its examination under varied experimental conditions is of the utmost importance for determining the real effects of various agents, and in many other ways it furnishes a valuable datum. PROC, AMER, PHIL, SOC, XLVII, 190 HH, PRINTED JANUARY 13, 1909. 522 JENNINGS—HEREDITY IN PROTOZOA. [April 24, chance of avoiding differences due to environment and growth. It is conceivable that congenital hereditary variations exist, but that they are few in number compared with those due to environment and to slight differences in ways of living, so that in our selection we always get the mere environmental variations. There are decided differences between the specimens of the same line beginning fission, as Table XIII. (page 442) well shows; here the length varied from 156 to 204 microns. It is possible that selection among specimens beginning fission might have a better chance for success. I have attempted this, but it is extremely difficult; I hope to return to it. We must consider, however, that if the non-inheritable differ- ences are so much more numerous and marked than the inheritable ones as to render conscious selection by human beings ineffective, they would apparently have the same effect on selection by the agencies of nature. The same ground for selection offered by heritable varia- tions is offered so much more fully by those not heritable that there would be as little effect in selection by nature as in selection by man. Certainly, therefore, until someone can show that selection is effective within pure lines, it is only a statement of fact to say that all the experimental evidence we have is against this. The results set forth in the present paper tend to strengthen that explanation of the observed facts regarding selection, regression, etc., in mixed populations, which is set forth by Johannsen (1903). We need not discuss these in detail here; they are essentially as follows: 1. Selection in a mixed population consists in isolating the various different lines already existing. 2. If selection is made, not of single individuals, but of consid- erable numbers having a certain characteristic, then by repeated selection it will be possible to approach nearer and nearer to a certain end. Thus, if we select from such a heterogeneous collection as is rep- resented in Table LXI. all the larger individuals, we shall have taken representatives of many different lines. Our selection will include the larger individuals of lines of median size, as well as the average individuals of lines of large size. The progeny of this selected lot will then consist of various lines, some larger, some smaller, but with the average higher than in the original collection. Another selection 1908.] JENNINGS—HEREDITY IN PROTOZOA. 523 will raise the average still further by getting rid of some of the smaller lines, etc. 3. It has been noticed that in many cases continued selection will not carry a character beyond a certain point. This is due (on the view we are setting forth) to the fact that we have finally isolated that line (or lines) of the original collection which had this character most strongly marked, and since selection of the fluctuations has no effect within the pure line, we can make no farther progress. 4. The phenomenon of so-called regression finds its explanation in the same way. It is found that when extremes are selected, the progeny of these extremes stand nearer the mean than did the par- ents, though they diverge in the same direction as the parents. The reason for this may again be seen by considering such a hetero- geneous collection as that of Table LXI., with the effects of selecting the extremes of size. If we select the largest and the smallest indi- viduals, we shall have taken (1) the largest individuals of the largest lines, and (2) the smallest individuals of the smallest lines. But these, when they propagate, produce, as we have seen, merely the means of the lines to which they belong. The largest individuals will produce then progeny that average smaller than themselves; the smallest individuals progeny that are larger than themselves; both sets will then approach the mean of the original collection as a whole. In working with populations reproducing by cross fertilization among the different lines, the conditions on which these results depend become quite obscured, owing to the introduction of new factors, the union of different factors, the appearance of mendelian results, etc. Work with pure lines perhaps shows the real cause for the observed phenomena above set forth. It must be admitted, then, that the work with pure lines, indi- cating that selection of fluctuations within the lines is powerless, leads to a simple and consistent explanation of many of the observed facts. But, of course, it gives no explanation of the origin of the different pure lines. Clear proof of the effectiveness of selection even within a pure line would therefore be of the greatest interest, and the present writer would find great pleasure in being the first to present such proof. But until such proof is forthcoming, it must be 524 JENNINGS—HEREDITY IN PROTOZOA. [April 24, admitted that the experimental results go strongly against the effect- iveness of selection among slight fluctuating variations in producing new inherited characteristics. How, then, do the different pure lines rise? This is after all the main problem. Toward its solution further investigations of this series will be directed. It is proposed to study in detail (1) the effects of conjugation on variation, heredity and the production of new races; (2) the effects of long-continued differences in environ- mental action on different divisions of the same line; (3) the ques- tion whether the different lines arise from something like mutations. Further, (4) additional different way of exercising selection within a single line will be tested. The question may be raised whether the production “by mutation” of such slight differences in size as we are here dealing with would not be essentially the same as their production by the inheritance of slight variations—since the extent of the “ mutations”’ would not be greater than what we should call slight variations in size. The difference between the two conceptions almost or quite vanishes when we come to deal with such minute changes in characteristics as those we find in the different lines of Paramecium. The “ mutation” would be merely a rare, heritable, variation, and it is now clear that heritable variations in size are much rarer than had been supposed; their number is so small that in Paramecium they are not statistically detectible among the many non-heritable fluctuations due to the environment. RAQUETTE LAKE, NEw York, August 22, 1908. $8) JENNINGS—HEREDITY IN PROTOZOA, 525 LIST OF LITERATURE. Calkins, G. N. 1906. The Protozoan Life Cycle. Biol. Bul., 11, 229-244. Calkins, G. N. 1906. Paramecium aurelia and Paramecium caudatum. “ Biological Studies ” by the Pupils of Wm. T. Sedgwick, Chicago. Davenport, C. B. 1899. Statistical Methods, with Special Reference to Biological Variation, New York. 1904. Idem. Second edition. Donaldson, H. H. 1906. A Comparison of the White Rat with Man in Respect to Growth. Boas Memorial Volume, New York, pp. 5-26. Hanel, Elise. _ 1907. Vererbung bei ungeschlechtlicher Fortpflanzung von Hydra grisea. Jenaische Zeitschr., 43, 321-372. Jennings, H. S. 1908. Heredity, Variation and Evolution in Protozoa. I. The Fate of New Structural Characters in Paramecium, with Special Reference to the Question of the inheritance of Acquired Characters in Protozoa. Journ. Exp. Zool., 5, 577-632. Johannsen, W. 1903. Erblichkeit in Populationen und in reinen Linien. 68 pp. Jena. Johannsen, W. 1906. Does Hybridisation Increase Fluctuating Variability? Report of the Third International Conference (1906) on Genetics. London. McClendon, J. F. 1908. Protozoan Studies, I. Journ. Exp. Zool., 6. Pearl, R. 1907. A Biometrical Study of Conjugation in Paramecium, Biometrika, 5, 213-297. Pearl, R., and Dunbar, F. 1905. Some Results of a Study of Variation in Paramecium. Seventh Re- port Michigan Acad. Sci., pp. 77-86. Pearson, K. 1902. Note on Dr. Simpson’s Memoir on Paramecium caudatum. Bio- metrika, 1, 404-407. Robertson, T. B. 1908. On the Normal Rate of Growth of an Individual and its Biochemical Significance. Arch. f. Entw.-mech., 25, 582-614. Simpson, J. Y. 1902. The Relation of Binary Fission to Variation. Biometrika, 1, 400-404. Yule, G. U. 1897. On the Theory of Correlation. Journ. Roy. Statistical Society, 60, 1-44. 526 JENNINGS—HEREDITY IN PROTOZOA. APPENDIX. TABLES OF MEASUREMENTS. [April 24, The first twenty-eight tables are distributed through the text. Tables XXIX. to LXIII. follow. TABLE XXIX. Correlation Table for Length and Breadth of 59 Specimens, Age o to 5 Minutes. (See Lot 2, Table 10.) Descendants of D. Length in Microns. a 76 80 84 88 92 96 100 104 108 112 116 120 124 128 132 = 36 I x S 4o baer Gra PR 6 44 2 40) Eee CET aL, ae 21 48 Rigg 2g a ee I.62 ta a i I I | 3 I 1 EN Sra I 10 ~~ 56 I © Bey Ps 2 DE BB a BS ee oe Length—Mean, 107.660 + 1.296" Breadth—Mean, 46.372 ~& .332¢ St. Dev., 14.780 .o16u St. Dev., 3.804 + .236u Coef. Var., 13.729 + .868 Coef. Var., 8.200 = .524 Mean Index, 44.037 per cent.; Coef. Cor., — .3138 + .0792. TABLE XXX. Correlation Table of Length and Breadth for a Random Sample of Lot 2, Table X—Same Lot from which came Specimens in Tables VII. and XXIX. Descendants of D. (24 hours in fresh hay infusion: July 17.) Length in Microns. , FTSSSTSLSTZRS TELE =| = 36 One aes gig I 8 S 40 12. 8) Ae 8 GR) oO Se 43 44 2°00 3°22 ee Fe eee I 57 & 48 ae ie Wha eye a ie nee ae a 43 = 52 > HAROLD eh 2 3°20 Aa 2s ~ 56 4 I PU so arin 1| 15 © 60 rg 2 " 1°00 2 2°7 14 9 8 14 13 14 18 18 22 17 17 12:7 50 Length—Mean, 184.100 + .776u Breadth—Mean, 46.020 + .251K St. Dev., 16.264 + .548u St. Dev., 5.256 = .1776 Coef. Var., 8.834 + .300 Coef. Var., 11.421 = .390 Mean Index, 25.084 per cent.; Coef. Cor., .4282 + .0389. 1908.] JENNINGS—HEREDITY IN PROTOZOA, 527 TABLE XXXI. Correlation Table for the Length and Breadth of the Young of Lot 6, between the Ages of 0 and 19 Minutes. (See Table X., row 7.) Length in Microns. 108 112 116 120 124 128 132 136 140 144 148 152 a & l 5 52 I 2 3 Ser ee otk OB eo I 6 = 60 | 2 eg 1/8 Ee 64 I ee I 4 a 68 I I 72 I I » op Ee = ma “De CR CRE ae Veiae ae nee An Wea eae ee Y Length—Mean, 128.000 + 1.908u Breadth—Mean, 60.168 + .788u St. Dev., 13.856 + 1.348" St. Dev., 5.712 = .556u Coef. Var., 10.825 + 1.066 Coef. Var., 9.495 + .933 Mean Index, 47.573 per cent.; Coef. Cor., — .0337 + .1375. TABLE XXXII. Correlation Table for Length and Breadth of Young of Lot 7, between the Ages of 0 and 19 Minutes, Descendants of Individual D. (See Table X., row 13.) Length in Microns. g 108 112 116 120 124 128 132 136 140 144 148 152 156 160 im oO “= 26 I I a a I I I 3 44 3 1 pe Ae RE tame ie ge ty ie < 48 ieihe one ee Bs oka are tr lige 3 52 | RS ee era a I 9 é Bae OE gee ge A Oe a ae oR a HBS Length—Mean, 134.256 + 1.663u Breadth—Mean, 46.768 + .4084 St. Dev., 15.394 + 1.176" St. Dev., 3.792 = .288u Coef. Var., 11.468 + .857 Coef. Var., 8.109 + .623 Mean Index, 35.643 per cent.; Coef. Cor., —.2546 + .1010. 528 JENNINGS—HEREDITY IN PROTOZOA.° _[Aprilag, TABLE XXXIII. Correlation Table for Length and Breadth of Young of Lot 6, between the Ages of 18 and 28 Minutes. (See Table X., row 8.) Length in Microns, g 132 136 140 144 148 152 156 160 =) = 48 | 5 5 = 52 Be 67s ae ae ee 22 56 | 2 4 3 2 I I 13 < 60 I 2 I I I I 7 > 64 I I 2 s med B > itil Nes Wes 9 MME ae Aas eat ek Length—Mean, 143.348 = .624u Breadth—Mean, 54.284 + .364" St. Dev., 6.480 = .440H St. Dev., 3.788 + .260¢ Coef. Var., 4.521 + .309 Coef. Var., 6.976 + .478 Mean Index, 37.921 per cent.; Coef. Cor., 1937 + .0927. TABLE XXXIV. Correlation Table for Length and Breadth of 106 Specimens, Age 18-28 Minutes. (See row 15, Table X.) (Descendants of D, but taken part one day, part another.) Length in Microns. 112 116 120 124 128 132 136 140 144 148 152 156 160 164 168 vs 8 36/1 I & 40 I % S 44 ee Be Oat. ety Mek eke ete: | 14 : 48 Pe Wh LOe Olay ee eee Li Wige Se Tg Ue eee ana Ne 31 = 56 TA” I oa I th 17 60 Te 1 Aiea ia Bee BE 7 2 64 I I 2 4 I 0 0 f 2:7. T2190 20 131004 3) oe Length—Mean, 143.812 + .544u Breadth—Mean, 50.832 + .3204 St. Dev., 8.296 + .384u St. Dev., 4.900 + .228u Coef. Var., 5.769 + .268 Coef. Var., 9.640 = .451 Mean Index, 35.438 per cent.; Coef. Cor., 1319 + .0644. 1908. ] JENNINGS--HEREDITY IN PROTOZOA, 529 TABLE XXXV. Correlation Table for Length and Breadth of Young of Lot 6, between the Ages of 35 and 45 Minutes. (See Table X., row 9.) Length in Microns. Z 132 136 140 144 148 152 156 160 S48 | = 48 I I I = 52/1 I I I I I 4 .8 56 2 I 2 I t 4 9 .< 60 I I I 3 ~~ 64 | I I I I 4 ie | mo , Reus | 5 EN Ri oe Bre geo eae Length—Mean, 149.920 = I.012« Breadth—Mean, 55.840 + .636" St. Dev., 7.512 .716u St. Dev., 4.724 + .452¢ Coef. Var., 5.010 .479 Coef. Var., 8.461 + 813, \ Mean Index, 37.296 per cent.; Coef. Cor., .2799 + .1243. TABLE XXXVI. Correlation Table for Length and Breadth of Young of Lot 6, between the Ages of 75 and 90 Minutes. (See Table X., row 10.) Length in Microns. 140 144 148 152 156 160 164 168 172 176 180 mn Se 40'| 1 I o 44 re) S 48/1 2 I I I I I 8 i 5 I 6 I 4 I 36 = 56 I 4 T 6 S 60 I 2 I I 2 I 8 ZS 64 o L 68 I I I 3 fata) PEAR Ys EN SN Le Ay ARDS VL Ges Aa ees ee MUR Length—Mean, 161.524 + 1.0044 Breadth—Mean, 54.192 — .600u St. Dev., 9.648 + .712u St. Dev., 5.752 = .424m Coef. Var., 5.074 .441 Coef. Var., 10.617 + .790 Mean Index, 33.558 per cent.; Coef. Cor., .5232 + .0756. 530 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE XXXVII. Correlation Table for Length and Breadth of Young of Lot 9, between the Ages of 3 and 4 Hours. (See Table X., row 16.) Length in Microns. dj 132 136 140 144 148 152 156 160 164 168 172 176 £ 40 I I S A4 I I 3 I 2 I 9 A ght 2 iy Rie RRR hg tag) rg I 27 & 52 Aika os) 2 A ae Min: Pa? aeenee savehaee er. 30 i 56 GE Pci ae Vee 17 + 60 2 I I I I 6 © 64 I = | 3 an 2 yA OS IRE MOTE ADEE «> SRN cs oT Wg ORS I I | 93 Length—Mean, 149.636 + .688u St. Dev., 9.856 + .488u Coef. Var., 6.587 + .327 Breadth—Mean, 51.568 + .322¢ St. Dev., 4.752 + .236u Coef. Var., 9.212 + .459 Mean Index, 34.546 per cent.; Coef. Cor., .3201 + .0628. TABLE XXXVIII. Correlation Table for the Length and Breadth of Young of Lot 9, between the Ages of 4.20 and 5 hours. (See Table X., row 17.) Length in Microns. 164 168 172 176 180 184 188 192 196 200 204 208 212 216 60 I Breadth in Microns. B 52 p OVERS vamhy Newt. ihhty catia II Lol Une ee RD bine eter pur a Satin yl Sh 9 26 BE eae aN a ae 23 b GP ND, SHPO Mac Meera (STEN REC 24 I : eth es il eA ic 6 Ee I 4 I I De 22 Oo P58 2 Bl Gee iets Grr 186.736 + .652" Breadth—Mean, 60.168 .360¢ Length—Mean, St. Dev., 9.416 + .460" Coef. Var., 5.043 + .247, St. Dev., 5.224 + .256u" Coef. Var., 8.679 + .428 Mean Index, 32.225 per cent.; Coef. Cor., .5557 + .0478. { 1908.] JENNINGS—HEREDITY IN PROTOZOA, 531 TABLE XXXIX. Correlation Table for Length and Breadth of Paramecia at the Age of 12 Hours. (Descendants of D; See Table X., rows 20 and 21.) Length in Microns. SSISESSSSLLS TSS GS gee e Lon] Lon - ae La | Lal Lan _ La - _ Lan | te - Lon! N N N N N 2 48 |1 I 2 B52|' t I 2 = 56 Eo Sake es 2 yaya Re I2 = 60 Chet De ae ae ae aa a 15 8 64 I yak nee Re I | 21 i 68 4°33 20% 13 % 72 145 I 7 S76 ° a 80 . é Poe OO! Oa On Bt 24° 4.7 14 12 10905) OC Oe bee Length—Mean, 188.988 = .996u Breadth—Mean, 62.796 + .464u St. Dev., 12.612 + .704u St. Dev., 5.872 + .328u Coef. Var., 6.672 + .374 Coef. Var., 9.350 + .526 Mean Index, 33.275 per cent.; Coef. Cor., .4868 + .0602. TABLE XL. Correlation Table for Length and Breadth of Paramecia at the Age of 18 Hours. (Descendants of D; See Table X., row 22.) Length in Microns. ra 168 172 176 180 184 188 192 196 200 204 208 212 216 220 224 228 5 48 Bey I 5 S 52/1 1 ESS GOR PON Hema OL Te ER. SRS AER 31 e 56 I Titre tay eS Ar ia et ee Bi at 30 ‘= 60 BE Darn -teeaat: Sateen” rine Taw (Neg I 26 S 64 I LSE: RSNA: MUI ARES 2 II ' 68 2 2 (3) a cS de Tine Same SN Aa Snel Warne Ys Ui ah) aie NR eae ae Length—Mean, 199.048 + .780u Breadth—Mean, 56.4906 = .292h St. Dev., 11.844 + .552u St. Dev., 4.428 + .208 Coef. Var., 5.949 + .278 Coef. Var., 7.837 + .367 Mean Index, 28.427 per cent.; Coef. Cor., 4304 + .0536. 532 JENNINGS—HEREDITY IN PROTOZOA. TABLE XLI. [April 24, Correlation Table for Length and Breadth of 300 Paramecia at the Age of (Descendants of D; See Table X., row 23.) .- 24 Hours. Length in Microns. 140 144 148 152 156 160 164 168 172 176 180 184 188 192 196 200 5 28 | I I 5 ie Jet ae: ee eine ONE it «CS Sa Se 43 = 36 ihr Mee ietaals hae tafe fo pace Ae AS 9 I 66 = 4° ie VaR ONE RAR SR MD pie BRS BT Pac 69 “A 44 I eS I Oe eB I I 65 = 48 eg eee ek Ma iM ete «pile Peek 1 | 36 % 52 2 Bina 2 Io © 56 I 2 TOR AN 6 ‘vy 2 £ § 34.20 27 40 52 390 32 26 14 12 3 2.) aes Length—Mean, 168.532 + .419u Breadth—Mean, 40.320 + .230K St. Dev., 10.768 + .296u St. Dev., 5.892 = .162u Coef. Var., 6.389 + .175- Coef. Var., 14.615 = .411 Mean Index, 23.899 per cent.; Coef. Cor., .5496 + .0272. TABLE XLII. Correlation Table for Length and Breadth of 62 Dividing Specimens of Lot 2. (Descendants of D; See Table X., row 31.) Length in Microns. ~ 3 144 148 152 156 160 164 168 172 176 180 184 188 192 196 200 204 208 212 is) 3 40 I I S 44 | 1 22 I 6 oe 48 bPEMCe Wei: Uehie Ae me fe une Ieee abe: Me a I | 20 52 AO MR ek a kate Mee ae I I 26 S 56 1 Nea ae Tighe Ae 8 3 60 I I ed hee Q It °2) 4°97 12 4-60 14 (4°20 2°o" 2.) ae Length—Mean, 171.548 + 1.1884 Breadth—Mean, 50.388 + .308 St. Dev., 13.848 + .840ou St. Dev., 3.584 .216u Coef. Var., 8072+ .492 Coef. Var., 7.111 + .433, Mean Index, 29.583 per cent.; Coef. Cor., — .1136 = .0840. 1908, ] JENNINGS—HEREDITY IN PROTOZOA, 533 TABLE XLIII. Correlation Table for Length and Breadth of Specimens in Early Stages of Fission: Constriction less than one-fourth Breadth. Lot 2. (See Table 10, row 30.) Length in Microns. Z 144 148 152 156 160 164 168 172 176 180 8 44 | I I 2 ite = 48 I i I I aaa 1 | 12 S52 I I 2 2 6 I 3 I Eh 56 I 2 I I 5 3 60 I I Rs I I GAN ar alae EUG 1 MMR ne « RRL eu Ca Length—Mean, 165.200 + .936" Breadth—Mean, 50.700 + .364u St. Dev., 8.788 = .664u St. Dev., 3.432 + .260K Coef. Var., 5.320 + .402 Coef. Var., 6.769 + .513 Mean Index, 30.765 per cent.; Coef. Cor., .1048 + .1055. ‘ TABLE XLIV. Correlation Table for Length and Breadth of Early Stages of Fisson, in Lot 3. (Depth of Constriction less than one-fourth Breadth.) (See Table X., row 24.) Length in Microns. 152 156 160 164 168 172 176 180 184 188 1092 Z 48 I I & 52 ° = 56 | 2 3 I 6 = 60 7 ee I 4 = 64! 1 3 2 2 I I 10 < 68/1 I 2 Ke I as iy 8 392 I I 2 4 —Q Kote 4 I 8 8 4 8 3 2 2 I 1 | 42 Length—Mean, 167.620 + .g96u Breadth—Mean, 65.716 + .706u St. Dev., 9.564 + .704" St. Dev., 6.784 = .499H Coef. Var., 5.706 + .421 Coef. Var., 10.322 + .768, Mean Index, 39.286 per cent.; Coef. Cor., .2215 + .0999. 534 JENNINGS—HEREDITY IN PROTOZOA. | April 24, TABLE XLV. Correlation Table for Length of Body and Depth of Constriction in 119 Dividing Specimens of the Aurelia form, Descended from c. (See Lot 4. Tables VIII. and X.) Length in Microns. b 5 MrTIOPVMrAOMrOmngqyngaynroannreoh 3 SORARKASSSSPLRKLSSBELSLAERBS = be A coe Ee Oo oe oe | 3 EEO Se ee eG. Br ne 54 a Ogee I Pr ae AR I2 S 10.0 I Fee re oie I 8 ‘5 13.3 P32 Ae 10 2 16.7 1 SR Sa 3 9 $ 20.0 ee 14211 13 E 23.3 I I 3 I 6 © 26.7 a 2 Talk 5 uw, 30.0 I I 2 ? 333 : I tt 4 S rae = 1 1° 6)\3'15 161313 8 7.116 3 8 2.1.2 00 fo) 1ee QA Length—Mean, III.541 + .797K Depth of Constriction, Mean, 10.504 St. Dev., 12.898 + .564u St. Dev. 8.431H Coef. Var., 11.563 + .512 Coef. Cor., 7862 + .0236. Increase in length with 10m increase in depth of Constriction, 12.027#. TABLE XLVI. Correlation. Table for Length of Body and Depth of Constriction in 63 Dividing Specimens of the Aurelia form, Descended from c. (See Lot 5, Tables VIII. and X.) Length in Microns. ps 2 D> onm . Of Oo > 69."Rs |) ose: a ee fo) “9 Lae) 0. 4 6. 0. 2010 0 9 OO. 8 NE eee ; RESSSEFSRFS SSRIS EES A 3.3 ‘ 3 7 4 5 4 I 25 = 6.7 2: 221. Si-2 Io Io. i. 2 3 & 13.3 2 ae 4 3. 36:7 I I ‘4 20. 2 @ 2 2 23.3 Pcs Oo 26.7 I I I 3 Y 30. rata 3 I I 6 S 333 I ES WB : Ri: o 1 0o'3 0 8 1 8 7 8's 6 Sar te or ae Q JENNINGS—HEREDITY IN PROTOZOA. TABLE XLVII. 535 Correlation Table for Length and Breadth of Dividing Specimens of Lot 4, in which the Depth of Constriction was Less than one-fourth the Breadth. (Aurelia form, Descendants of c.) (See Table X., row 33.) _ Length in Microns. 4 vi LAR Weks Bh RSUG i ee Bites Sate ee Toutes ah Ege ate S oe Bee ee a ae fo) = Lael Lal Lani Lal Lal Lal Loni Lani . a) = 26.7 | 1 I a 30. Be Ae ae ie Ae Se T II iS 33.3 2 LEO By BT 24 i 36.7 ge iieg EY CONE. aa I 20 > 40. yA ah I I 7 © 43.3 2 I ae oy a Re Me eR A i ir ROR ES AGN ee a Length—Mean, 103.737 + .650" Breadth—Mean, 34.850 + .2876 St. Dev., 7.823 + .3790u St. Dev., 3.453 — .2034 Coef. Var., 7.541 + .445: Coef. Var., 9.911 + .587 Mean Index, 33.623 per cent.; Coef. Cor., .6502 + .0479. TasLeE XLVIII. Correlation Table for Length and Breadth of Dividing Specimens of Lot 5, in which the Depth of Constriction was Less than one-fourth the 45.263 = .507¢ 5.463 = .423¢ Breadth. (Aurelia form, Descendants of c.) (See Table X., row 36.) Length in Microns. i? ag ay ene ee ai uan se AMER I, PE ee Fete) Ok B88 8 eae = EY EN PT Le EN ee AEE. © 333 | 1 2 SS 36.7 I a 40. I aig I & 43.3 I Prat Sea <= 46.7 2 Ces EON % 50. I Ber ines a TS its. ® 53-3 oo (56.7 ANS a nM 2 Mic Seal en NC wat bes ia at Length—Mean, 113.333 + .850u Breadth—Mean, St. Dev., 7.778 + .603¢ St. Dev., Coef. Var., 6.862 + .533 Mean Index, 39.903 per cent.; Coef. Cor., .6744 = .0507. Coef. Var., 12,071 = .947 ~ Breadth in Microns. 20. 23.3 26.7 30. 33-3 36.7 4o. 43.3 46.7 50. 536 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE XLIX. Correlation Table for Length and Breadth of a Random Sample of Lot 4. (See Table to. Aurelia form, Descendants of c. Many dividing.) Length in Microns. 0 RR OO RS ee fem ieee es ee RAG HSARAE SSS OLR SS Sees eessgs ; oe | a I I I Ne MU Pas ite at Hane algae” I I IRS HOE Sak Ma OB to et SEN ane er I Ha I Ae es A lin ay A Ne BA ees SMS. Son ah: SN BER De” alu eee. 24 1 3 q I I 2 AR REE OG On ag ot ae ae I I I I a I De I I 2 bE Tee 8) | I 2207 6 2:7 12.19 13 18:16 17 19 16 Jo 12,12: 85 4°97 2) eee Length—Mean, 114.163 + .784u Breadth—Mean, 34.207 + .241K St. Dev., 17.443 = .555¢ Coef. Var., 15.279 + .407 Mean Index, 30.177 per cent.; Coef. Cor., .6757 + .0244. TABLE L. Correlation Table for Length and Breadth of a Random Sample of Lot 5 (Table X.). Aurelia form; Descendants of c. 24 Hours in a Fresh Hay Infusion. Length in Microns. St. Dev., 5.363 + .171K Coef. Var., 15.683 = .511 ry Te Ns rie ha cr AR et SBS $RRRE SES ESP Ses asses 2 36.7 aig one 7 & 40. | 1 i ame sees ests at fa 14 S 43.3 ae Aiakc ae ala a Me Aage A 22 46.7 I I ens ane 13 2 50. I Avec S rere Lee I 19 = 53.3 I Dam he habe tea a 13 S 56.7 hee a ee 6 $ 60. I 2 I 4 oo 63.3 I I 66.7 Tne Por 2g 801g 4 ie 9410: 8 Se Se 2 ee Length—Mean, 114.033 + .820u Breadth—Mean, 47.300 = .4374 St. Dev., 12.140 + .580u Coef. Var., 10.646 + .513 Mean Index, 41.455 per cent.; Coef. Cor., .8152 + .0226. St. Dev., 6.490 + .310H Coef. Var., 13.720 + .667 Breadth in Microns. 1908. | JENNINGS —HEREDITY IN PROTOZOA. 537 TABLE LI. Correlation Table for Length and Breadth of a Random Sample of the Culture from which came the Young of Lot 6, Table X., after 24 hours in fresh hay infusion. (See row 2, Table XVIII.) Length in Microns. 156 160 164 168 172 176 180 184 188 192 196 200 204 208 212 216 220 224 44 I I 3 48 2 I 3 5B 52 sae Or 2 8 % 56.) 1 2 oie I I Io 3 60 I j ern Os ce Wana: tae? (AEN a a 14 64 Bien ea hrs Cn a I 18 © 68 Bite Dine Sey > i ea I 1g S 72 2 See eR NS 3 13 76 Bi 1S Wee Ra | 9 & 80 I I mr 84 2 I 3 88 I I a A ee eo 8. Te Se 8 Bg. ee See ee Length—Mean, 184.680 +’ .848u Breadth—Mean, 64.880 + .580u St. Dev., 12.596 + .600" St. Dev., 8.624 + .412u Coef. Var., 6.821 + .327 Coef. Var., 13.292 + .645- Mean Index or Ratio of Breadth to Length, 35.131 per cent.; Coef. Cor., 6469 = .03092. Tase LII. Correlation Table for Length and Breadth of Descendants of D, in Culture Fluid where Injurious Bacteria have Multiplied. June 25. (See row 5, Table XVIII.) Length in Microns. ® SSFSRBSSTSRRSASARBSFTSRSRSLIVRASSIS SS CN co I oe oe oe oo S.A. Me. a Be. A De | I I I I I Ae NG See Halas Sie 2 I Tara tO bm Nae yo ks ee aa I ates 5 ah BS Ts Ti WE I I 4 1 Fi Re Dy Se eS eo ge ay igs sg Ie I a ele ae Bae 2a. 4 I I 2 a3" ee I I I i-3 S Sid es4 2 ae | BF I I I I Ot 0.3% 4.1.6 8 1435 6S Seeger A210 8S 7 Faas OT? Length—Mean, 201.888 + 1.147H Breadth—Mean, 56.112 + .305¢ St. Dev., 22.680 811K St. Dev., 7.808 + .279" Coef. Var., 11.233 + .407 Coef. Var., 13.913 + .507 Mean Index or Ratio of Breadth to Length, 27.850 per cent.; Coef. Cor., 6771 + .0274. PROC, AMER, PHIL. SOC. XLVII. 190 II, PRINTED JANUARY 13, 1909. 538 JENNINGS—HEREDITY IN PROTOZOA. [April 24, TABLE LIII. Correlation Table for Length and Breadth of a Starving Culture of De- scendants of D. Eleven days in small watch glass of hay infusion, not renewed. (See row 6, Table XVIII.) Length in Microns. 128 132 136 140 144 148 152 156 160 164 168,172 176 180 184 188 - =| 2 28 3 ae 6 3 32 | I AORN il ce SEN ER 18 = 36/1 2556) pe a 8 I I 27 Ee RD Meee Sora A kr A, Eee Oia ae Ip I 24 cc 44 SE ae ee 2 a. I | 19 > 48 Bie: SOO 4 a 3 4. 4 16°12 45) 205-9509. 4 4 2.0 Length—Mean, 149.360 + .736u Breadth—Mean, 38.080 + .356u St. Dev., 10.896 + .520” St. Dev., 5.288 = .252¢ ’ Coef. Var., 7.296 + .350 3 Coef. Var., 13.881 + .675 Mean Index or Ratio of Breadth to Length, 25.515 per cent.; Coef. Cor., 4481 + .0530. l TABLE LIV. Correlation Table for Length and Breadth of Descendants of D,.in a rather Ill-fed Culture. September 15. (See row 13, Bable XVIII.) Length in Microns. ai SSSRRGBFSSRBSSSLLRSEIRS S x + + SS SH SH He He He He NN NNN NN AN A 5 4o A Age a 7 = 44 I Tbe Qe re 2 I I| 13 ¢ 4841 L222. FO Si a ee 30 ue BS BK ee he 2.4 3.363 4°34 3 50 $. 3 t2 I 1. ?. Qe s 60 I Ly o puis a I 0.0°% 1°3..7°12°8 32 O45 2 505° 6>050— eee Length—Mean, 202.280 + 1.031h Breadth—Mean, 49.600 + .208h St. Dev., 15.284 + .729¢ St. Dev., 4.412 + 210" Coef. Var., 7.556 .362 Coef. Var., 8.896 + .428 Mean Ratio of Breadth to Length, 24.593 per cent.; Coef. Cor.. .4085 + .0562. 1908. ] JENNINGS—HEREDITY IN PROTOZOA, 539 5 Tasie LV. Correlation Table for Length and Breadth of the Same Lot Shown in Table LIV., but after 48 hours in fresh hay infusion. September 15. (See row 14, Table XVIII.) Length in Microns. TSSSLTSSSSTSRRSTIS ARISES Le ee oe A | a 44 I I 4 48 x I a 52 Pie Sa51 2 Me 3 2 Io = 56 2.2.3" 4 AY 10 gE 60 eho S 4. aa ei 322 25 (4 I 3 eS oe ear ae 14 3 68 | 1 SC, 454 252 I | 20 $ 72 i I Ey) 402) Fei 15 5 76 ae Sas 3 80 I I PO ts Oe Li eOn FF 5.0). 10°0'..8 10.9). 12° 8) 5.2 5 oO goo Length— Mean, 175.320 + 1.060” Breadth—Mean, 63.160 + .472¢ St. Dev., 15.708 + .740% St. Dev., . 7.000 + .334" Coef. Var., 8959+ .431 Coef. Var., 11.083 + .535: Mean Ratio of Breadth to Length, 36.123 per cent.; Coef. Cor., -5376 + .0480. Taste LVI. Correlation Table for Length and Breadth of Descendants of c. August 9. (See row 17, Table XVIII.) Length in Microns. -o > co > CE RE Sp SI

(8° Q' 10:42. 9-5) 36 Oo eS ae OO OL Tee ‘Length—Mean, 123.666 + .813u Breadth—Mean, 33.600 + .400H St. Dev., 12.040 + .5734 St. Dev., 5.917 + .283u Coef. Var., 9.736 + .460, Coef. Var., 17.608 + .865 Mean Ratio of Breadth to Length, 27.136 per cent.; Coef. Cor., .6528 é .0410. 540 JENNINGS—HEREDITY IN PROTOZOA. [April 24 Taste LVII. Correlation Table for Length and Breadth of a Sample of the Non-Conju- gants of a Conjugating Culture of Descendants of the Individual c. Flourishing culture in a large vessel. September 25, 1907. (See row 21, Table XVIII.) Length in Microns. TRSSSFSSRBIESSSRES SS ASB 16 I I w 20 I I 5 24 211 2 6 5 28 |2 PM ie ee: tes Man 19 S 32 eek ae ge Ae ar eR: a 2.1 I I 24 e 36 eH Recta ofa ow aye by AIM feel HM I 42 “40 Wy She anh etary Air, ia Mt” Tce, Wa 1 | 48 S 44 MONE a ee 2255 Tug 2 pa a. 3 48 aes Ve I 4 223 3:5 22 & 52 I Aer eee I 2 9 FQ 56 I I 60 2 2 2 3 1013 11 19 14 18 19 11 15 8 7.14 6 12 5 7 3 3 ja00 Length—Mean, 158.800 + .8774 Breadth—Mean, 38.560 = .3534 St. Dev., 18.384 + .620u i. “St. Dew. 7.396 + .240H Coef. Var., 11.578 + .306 Coef. Var., 19.176 + .670 Mean Ratio of Breadth to Length, 24.244 per cent.; Coef. Cor., .7135 += .0234. Tasie LVIII. Correlation Table for Length and Breadth of Descendants of c, Five Days after Cessation of Conjugation. Food getting scarce. September 30, 1907. (See row 22, Table XVIII.) Length in Microns. 100 104 108 112 116 120 124 128 132 136 140 144 148 152 c 20 I I 2 S24) 1 I 2 4 = 28 Ati 3 I 14 = 32 CM Gemer Vent Wi cael Wee yale cles 20 = 36 raee wales Wade I ee ees ee 19 S! 40 | A: CANE UR He CO 3 44 Par Bere 7 5 48 peg I 3 TP) 6 yO Fo Be eM a i Length—Mean, 129.640 + .867% Breadth—Mean, 35.440 = .400/ St. Dev., 12.848 + .613u St. Dev., 5.928 + .2834 Coef. Var., 9.911 + .477 Coef. Var., 16.730 + .820 Mean Ratio of Breadth to Length, 27.262 per cent.; Coef. Cor., .7576 = .0287. 1908, ] JENNINGS—HEREDITY IN PROTOZOA, 541 Taste LIX. Correlation Table for Length and Breadth in a Large, Old Culture of Descendants of c, January 23, 1908. (See row 23, Table XVIII.) Length in Microns. SSSELBSTRESESSISSESSSSER 32 2 2 , 36 A ae 5 3 4o Sak ‘ees ab I 7 9 44 eed HR Oa ae a | 9 2 48] 1 I OR Tae ine pkey I 19 = 52 OND i” Jes Ca a I 10 a 56 Ce ee ae 2-1 14 ‘a GO OSs Als OE SOHAL Io S 64 “ee a tals 8 S 68 I 2 3 6 & 72 Ley 4 FA 76 pipes 4 80 ° 84 I I 2 OO he 8 Saw oS 1709 3 BF <4 eee Length—Mean, 144.880 + 1.0974 Breadth—Mean, 54.160 + .765u St. Dev., 16.264 = .776u St. Dev., 11.346 .541u Coef. Var., 11.224 .542 Coef. Var., 20.948 + 1.042 Mean Ratio of Breadth to Length, 37.106 per cent.; Coef. Cor., .8500 = .0187. Taste LX. Correlation Table for Length and Breadth of Descendants of c. Same Culture shown in Table LIX, but cultivated in small watch glass, January 30 to February 15, 1908. (See row 27, Table XVIII.) Length in Microns. | 76 80 8&4 8&8 92 96 100 104 108 112 116 120 fe) 5 16 I I = 20 | I ale SRR Aue 13 o 24 2 BRE 3 30 7. 28 3 SSS ER EF I I 39 S 32 igi oe Pas 13 ie 36 I 2 I 4 oO ra I fe) 3 cS G Citic prima. Sabot 2 BG aie 2 I |Ioo Length—Mean, 100.320 + .528u Breadth—Mean, 26.480 + .266" St. Dev., 7.828 + .373u St. Dev., 3.044 + .188u Coef. Var., 7.804 + .374 Coef. Var., 14.895 + .753 Mean Ratio of Breadth to Length, 26.321; Coef. Cor., .7671 + .0278. Breadth in Microns. 542 JENNINGS—HEREDITY IN PROTOZOA. TABLE LXI. Correlation Table for Length and Breadth of a Random Sample of the “Wild” Conjugating Culture M, January 29, 1908. 200 Non-con- jugants, 38 Conjugants. Length in Microns. [April 24, SSSISSBSTSXLLSSRSRLSSISLS RL TRSSe a oe oe oe oe > = = . . . | 28 ‘ I ps I 2 36 I SB 3 ges a i 40 2 2 Oe PS 2% 31 44 202 SE Gee a St he ee oe oe ee I 4) 48 {1 PS 32) ie ee 38 1 GF Eee I 52 52 I eae ee Oe Oye ee 8 I 4c 56 : idee GR Ip MAE ONS RA 5 ees ‘ré 60 |e 2 2 4 64 - ae ae ae, Si I I} 1c 68 I 2 3 7a. § I I II 72 I I a 76 2 I I 4 80 I I 2 84 c 88 I I 2 1201 3 3 7 7 182019 2418 9-17 26 18 1210 8 5 3 4G Taste LXII. Correlation Table for Length and Breadth of Dividing Specimens of Lot 1 (Table X.), in which Lengthening had begun. Breadth in Microns. wn roy than 4 microns deep.) Length in Microns. (Constriction more 160 164 168 172 176 180 184 188 192 196 200 204 208 212 216 220 224 Length—Mean, 2 I I I 5 a Fee Ba ge a ae ie ae OR ae I | ($0 2 TORO. MR oe eS aube ied aie Se 71 Pe as cy a ls ee Hd te a dig I 51 Fe Weel eateab ba MeN SR Ma 18 Poo 3 I 6 Oo I 2. 5 12 22 23 16 22 15 1612 9 96 3.03 ee 186.066 + .710K Breadth—Mean, 49.540 + .2154 St. Dev., 14.208 = .502" St. Dev., 4.296 = .152¢ Coef. Var., 7.636 + .271 Coef. Var., 8.671 + .309 Mean Ratio of Breadth to Length, 26.796 per cent.; Coef. Cor., —.0938 + .0406. 1908. ] JENNINGS—HEREDITY IN PROTOZOA. 543 Taste LXIII. Correlation Table for Length and Breadth of Dividing Specimens of the Aurelia Form (Descendants of c), in which Lengthening had begun. (See Lot 4, Tables VIII. and X.) Length in Microns. D> 2 => > oO c => 9, 0> ee Oe Oe ee SOM Se eae a xe He HF HH HH FH Y§ SS SH SH SOO lelaRlalUARlellleO = 26.7 I I I 3 S 30. oie eas ame | 2 Fa I 10 SES eM See SS. aid Derde t 18 36.7 I i a 2 II 40. I ee a8 I reg ZS 43.3 I I o 46.7 I I = Aa a ae SGT) OB Ng aH OO. 21. aD Re Length—Mean, 121.383 + 1.053u Breadth—Mean, 34.590 + .383u St. Dev., 11.367 + .743¢ St. Dev., 4.147 = .2736 Coef. Var., 9.365 .613, Coef. Var., 11.989 + .797, Mean Ratio of Breadth to Length, 28.648 per cent.; Coef. Cor., .3100 = .0837. 544 JENNINGS—HEREDITY IN PROTOZOA. [April 24, CONTENTS. PAGE I. INTRODUCTORY |: o-sik5/G:5)5/steee alata ers klar tera eaalete aus aed aa er ats telat ea 393 II. PRELIMINARY STUDY OF VARIATION IN PARAMECIUM.........e--e0<- 394 1. General Methods of Work: Statistical Treatment and its Uses. 395 2. A Typical Celture = i520 e's bas iev bars aly d hte en ota Ce 396 3. Methods of Measuring and Recording ..............ceeeeeeees 396 4. Method of Constructing the Polygons ................+ee0- 399 5. Two Groups: Of “Patamecia <2 ..0%55.6 bei sioas sae ade ee 402 6. Are Differences in Size Hereditary within Each of the Two LONG Fas ster aiegate 2 0 oss hnte, olden 00k a dying & 6 a -aeie ecls a 407 ; 7. Proposed Analysis of the Polygons of Variation.............. 409 IIT. GRow?tH IN “PARAMECIUM fi abs DV Reo holes © oho 0 oSe ae Doe 4II Effects of Growth on a Variation Polygon, p. 411; Material and Methods of Work, p. 414. 1. Description of the Different Stages of Growth................ 415 First Stage: The Young before Separation is Complete....... 415 a. The Unseparated Halves before Lengthening has Begun. 417 (1) The caudatum form (descendants of D), p. 417; (2) the aurelia form (descendants of c), p. 422. b. The Unseparated Halves after Lengthening has Begun. 423 Second Stage: The Young Immediately after Fission, up to the Age of Ninety Minutes...))..0....4.5 +200 seme 426 ce. Age 0 to 5 Minutes... cuinc csc daseee sts cuss ame 427 d. Age 0: to 19 Minutes ooc5 Sag «cicero cas 6 ous 6 9 le 432 é. Age. 18 to 28 Minutes. i006. i. c esac sca ses eee 434 f. Age 35 to. 45 Minutes (06. e280. .'s005 sacs 435 g. Age 75 to.90 Minutes. ....0.66.0.-. +0 eds) sue h. Age 0 to 90. Mitutes. ..0c.c0<.<6 00s ++ eso cue ey ee . 435 Third Stage: Three to Five Hours Old.................000- 436 t. Age. 3 to 4 “Hours ii caniebivs on cs Hale ee ee 436 j. Age 4.200 5 Hours... ie inn naw's bea ne ee 436 Fourth Stage: Twelve to Eighteen Hours Old.............. 437 hk. Age 12 Hours 0s i ciiecew cvs ciennsies cbiee nae eey an 437 lL. Age 18, Howré. iu. Foon nid oa oe een oe 438 Fifth Stage: Twenty-four Hours Old ......... 2s a eae a 438 Sixth Stage: Preparing for, Fission 2.00... 6.5.0 + caswien ee 439 Seventh Stage: Fission: is)6 ict. aise ce baw e060 443 m. Beginning Fission (.) is... ses