X PROCEEDINGS OF THE Iowa Academy of Science FOR 1909 VOLUME XVI EDITED BY T&E SECRETARY PUBLISHED BY THE STATE DBS MOINES EMORY H. ENGLISH, STATE PRINTER 1909 m- PROCEEDINGS OF THE Iowa Academy of Science FOR 1909 VOLUME XVI EDITED BY THE SECRETARY PUBLISHED BY THE STATE DES MOINES: EMORY H. ENGLISH, STATE PRINTER 1909 121.1/10 LETTER OF TRANSMITTAL. Des Moines^ Iowa^ July 20, 1909. To His Excellency, Beryl F. Carroll, Governor of Iowa: In accordance with the provisions of title 2, chapter 5, section 136, code, 1897, I have the honor to transmit herewith the proceedings of the twenty-third annual session of the Iowa Academy of Science and request that you order the same to be printed. Respectfully submitted, L. S. Ross, Secretary Iowa Academy of Science. IOWA ACADEMY OF SCIENCE OFFICERS OF THE ACADEMY. 1908. President — Samuel Calvuv. First Vice-President — F. F. Almy. Second Vice-President — S. W. Beyer. Secretary — L. S. Ross. Treasurer — H. E. Summers. EXECUTIVE committee. Ex-officio — Samuel Calvin, F. F. Almy, S. W. Beyer, L. S. Ross, H. E. Summers. Elective — R. B. Wylie, L. Begeman, D. W. Morehouse. 1909. President — Frank F. Almy. First Vice-President — G. L. Houser. Second Vice-President — A. C. Page. Seci'etary — L. S. Ross. Treasurer — George F. Kay. executive committee. Ex-officio — Frank F. Almy, G. L. Houser, A. C. Page, L. S. Ross George F. Kay. Elective — Samuel Calvin, N. Knight. C. 0. Bates. PAST PRESIDENTS. Osborn, Herbert 1887-88 Todd, J. E 1888-89 Witter, F. M 1889-90 Nutting, C. C 1890-92 Pammel, L. H '. 1893 Andrews, L. W 1894 Norris, H. W 1895 Hall, T. P 1896 Frankin, W. S 1897 Macbride, T. H ' 1897-98 Hendrixson, W. S 1899 Norton, W. H 1900 Veblen, a. a 1901 Summers, H. E 1902 Fink, Bruce 1 1903 Shimek, B 1904 Arey, M. F 1905 Bates, C. O 1906 Tilton, John L 1907 Calvin, Samuel 1908 VI IOWA ACADEMY OF SCIENCE MEMBERS OF THE IOWA ACADEMY OP SCIENCE. FELLOWS. Alden, W. C . .Mount Vernon Almy, F. P Akey, M. F Cedar Falls Baker, H. P State College, Pa. Bartholomew, C. E. Bates, C. 0 Beach, S. A Begeman, L Beknett, a. a Beyer, S. W Bouske, P. W Buchanan, R. E... Cable, E. J Calvin, S . Iowa City Clarke, J. P Cratty, R. I Armstrong CoNARD, Henry S . . Curtiss, C. F Da'std, Floyd Denison, 0. T Mason City Ende, C. L. von Erwin, A. T Fawcett, H. S . . .Gainsville, Fla. Fay, 0. J., Des Moines Pinch, G. E Fitzpatrick, T. J. . . Gow, J. E Cedar Rapids Greene, Wesley. . . . Guthe, K. E Guthrie, J. E Hadden, D. E Harriman, W. E Hendrixson, W. S. Hoeve, H. j Des Moines Houser, G. L Kay, George P Iowa City Kelly, H. M ...Mount Vernon Keyes, C. R King, Charlotte M. Kinney, C. N Des Moines Knight, N Larson, C Ames Learn, Clarence D Clermont Lees, James H Lorenz. C. P Iowa City Maeston, a Macbride, T. H Iowa City Martin, A. W Michael, L. G Miller, A. A Morehouse, D. W . . . . Des Moines Morrison, Edwin Oskaloosa Mueller, H. A St. Charles Newton, G. W Norris, H. W Norton, W. H Nutting, C. C Iowa City Page, A. C Pammel, L. H Peck, Morton E : . . . . , Salem, Ore. Place, B. A ...Ithaca, N. Y. Ricker, M Des Moines Rockwood, E. W..... Iowa City Ross, L. S Sage, J. R Des Moines Sanders, W. E Alta Seashore, C. E Iowa City Seavee, P. j .Mount Pleasant Sheppeed, B. E Des Moines Shimek, B Smith, A. G Iowa City Stanton, E. W Stevenson, W. H. . . . Ames Steomsten, Frank A. Iowa City Summers, H. E Ames Tilton, J. L Indianola Walker, E. R . . ! Marshalltov/n Watson, E. B Weld, Laenas G Wickham, H. F Iowa City Wilder, F. A Williams, I. A Wilson, Guy West. . Witter, P. M Wylie, R. B Iowa City IOWA ACADEMY OF SCIENCE Vll ASSOCIATE Achenbach, Naomi Marshalltown Aitchison, Miss Allison, B.Cedar Falls Andeeson, Joseph A Chance, Kans. Anthony, C. H Cedar Falls Arnold, John F Impgene Bailey, B. H .Cedar Rapids Baker, Jesse A Indianola Bartell, Floyd E Indianola Begg, a. S Des Moines Boyd, M. F Iowa City Brown, F. A East Peru Bryden, C. L Iowa City Buchholz, John T Mt. Pleasant Cameron, J. E Kansas City Cavanagh, Lucy M.. Iowa City Chapman, E. K Cedar Falls Churchill, C. H Fort Dodge Clearman,. Harriett Iowa City Conklin, R. E Des Moines Coss, J. A.... Fayette ' Crawford, G. E Cedar Rapids Curtiss, L. D Alta Edmondson, C. H Iowa City Edwards, J. W Mt. Pleasant Eldredge, C. Guy Sahula Ellyson, C. W Alta Fagen, Lester P Des Moines Feuling, Mrs. A. D Ames Fish, Fred A Ames Fogel, Estelle D Ames Getchell, Robt. W Ames Gose, Bert Pleasantville Greene, Carrie M Fayette Griffith, Mary Whittier, Cal. Griser, Samuel W Independence Hanson, F. V Hayden, Miss Ada Ames Henning, Carl Fritz Boone Hersey, S. F Cedar Falls Heuse, E. O Fayette Hockett, S. W Waterloo ILSLEY, H. E Iowa City Irwin, Keith J Jeffs, Royal E Ames Jenner, E. a Indianola Johnson, F. W 61 Wabash Ave., Chicago Kemp, Miss Elda Marion Kuntz, Albert Iowa City Lambert, J. J Iowa City Lazell, Fred J Cedar Rapids members. . Liddle, Leonard M Mount Vernon Lindly, j. M Winfield Ling, L. E. A Cresco Livingston, H. Hopkinton Longstreth, O. D lov/a City Maclean, Geo. E Iowa City McKenzie, R. M Fairfield Me Sweeney, Henry W estgate Meek, Vv^. J Oskaloosa Miles, Lulu. Mount Ayr Moody, H. W Fort Dodge Moorehead, G. C Ida Grove Morrison, J. W Alta Munroe, N. C Neff, Joseph H Fayette Ness, Henry Ames Nickle, Clarence E Des Moines Nollen, Sara Grinnell Olson, O. M Fort Dodge Osborn, B. F Rippey Phillips, Mrs. Gertrude Grinnell Rainey,' F. L Fairfield Richardson, Miss Florence • Des Moines Roberts, T St. Charles Robinson, C. L Norwalk Robinson, J. W Grand River Scott, C. A Ames Simpson, H. E Waterville, Me. Smith, F. J Des Moines Smith, G. L Shenandoah Somes, M. P, Iowa City Stauffer, Ellis B State Center Stevens, T. C Sioux City Stoddard, Blanch Iowa Falls Storms, A. B Ames Thomas, A. O Wellman Treat, Jos. A Stuart Treganza, j. a Britt Van Hyning, Tfiompson . . . Des Moines Walters, G. W Cedar Falls Warren, Edna M Grinhell Webster, R. S Ames Weld, L. D Cedar Rapids Wheat, A. J Emmetshurg Wheat, G. G Emmetshurg Wheeler, Forest Fort Dodge Wheeler, Ward H Mount Vernon Wolden, B. O Wallingford Vv^ooDRow, Harry R Des Moines IOWA ACADEMY OF SCIENCE viii CORRESPONDING MEMBERS. Andrews, L. W St. Louis, Mo. Arthur, J. C Purdue University, Lafayette, Ind. Bain, H. P University of Illinois, Urbana, 111. Ball, C. R ....Department of Agriculture, Washington, D. C. Ball, E. D State Agricultural College, Logan, Utah Barbour, E. H State University, Lincoln, Neb. Bartsch, Paul Smithsonian Institution, Washington, D. C. Beach, Alice M University of Illinois, Urbana, 111. Bessey, C. E State University, Lincoln, Neb. Bruner, H. L Irvington, Ind. Carver, G. W Tuskugee, Ala. Conrad, A. H 18 Abbott Court, Chicago, 111. Cook, A. N University of South Dakota, Vermillion, S. Dak. Craig, John ! Cornell University, Ithaca, N. Y. Drew, Gilman C Orono, Maine Eckels, C. W University of Missouri, Columbia, Mo. Faurot, F. W Missouri Botanical Garden, St. Louis, Mo. Fink, Bruce Oxford, Ohio Franklin, W. S Lehigh University, South Bethlehem, Pa. Frye, T. C State University, Seattle, Wash. Gillette, C. P Agricultural College, Fort Collins, Colo. Goodwin, J. G East St. Louis, 111. Gossard, H. A Lake City, Fla. Halsted, B. D New Brunswick, N. J. Hansen, N. E Brookings, S. Dak. Haworth, Erasmus State University, Lawrence, Kan. Heileman, W. H Pullman, Wash. Hitchcock, A. S Department of Agriculture, Washington, D. C. Leonard, A. G Grand Porks, N. Dak. Leverett, Prank Ann Arbor, Mich Mally, P. W Hulen, Texas McGee, W. J Bureau of Ethnology, Washington, D. C. Meek, S. E Field Columbian Museum, Chicago, 111. Miller, B. L Bryn Mawr, Pa. Mills, S. J Denver, Colo. Newell, Wilmon Capitol Building, Atlanta, Ga. Osborn, Herbert State University, Columbus, Ohio Owens, Eliza.. Bozeman, Mont. Patrick, G. E Department of Agriculture, Washington, D. C. Price, H. C.. State University, Columbus, Ohio Read, C. D Weather Bureau, Sioux City Repp, J. J Philadelphia, Pa. Savage, T. E Urbana, 111. IOWA ACADEMY OF SCIENCE ix SiERiNE, Emma ...Dysart, Iowa SiRRiNE, P. A 124 South Ave., Riverhead, New York Spencer, A. C U. S. Geological Survey, Washington, D. C. Todd, J. E Lawrence, Kan. Trelease, William Missouri Botanical Gardens, St. Louis, Mo. Udden, J. a Rock Island, 111. Weems, J. B Alleghany, West Va. Winslow, Arthur Kansas City, Mo. Youtz, L. a New York City, N. Y. IOWA ACADEMY OF SCIENCE TABLE OF CONTENTS Page Letter of Transmittal \[[ Officers of the Academy v Membership of the Academy vi Table of Contents x Report of the Secretary 1 Amendment to the Constitution 3 Treasurer’s Report 3 Officers for the Year 1909-10 3 Program 4 Resolutions on Darwin - 5 Necrology 7 President’s Address, by Samuel Calvin. . 11 The Polyporaceae of Payette, Iowa, by Guy West Wilson. 19 Some Parasitic Polyporaceae, by Clarence D. Learn. 23 The Underground Organs of a Pew Weeds, by L. H. Pammel and Estella D. Pogel 31 Notes on Pactors in Pungus Diseases of Plants, by L. H. Pammel and Charlotte M. King 41 The Plora of Iowa Rock, by R. B. Wylie 99' The Action of Manure on a Certain Soil, by E. B. Watson 103 The Okoboji Lakeside Laboratory, by Thomas H. Macbride 131 Some Peatures of Iowa Ground Water, II, by W. S. Hendrixson 135 The Analysis of Smaltite with Special Reference to the Estimation of Arsenic and Cobalt, by Nicholas Knight 143 The Pruit of Viburnum Nudum, by Robert H. Lott and Nicholas Knight. . 145 Significance of Thrust-Planes in the Great Basin Ranges,^^by Charles R. Keyes 151 Orotaxial Geologic Correlation and Diastrophism, by Charles R. Keyes.. 153 Carbonic Column of Rio Grande Region, by Charles R. Keyes 159 The Hysteresis Loop, by D. Y/. Morehouse and Harry Ray Woodrow 165 The Googler Primary Battery, by Harry Ray Woodrow 167 Effect of Temperature Inequalities on the Balance, by L. D. Weld 181 Evaporation from Pfee Water Surfaces, by Arthur G. Smith 185 The Pifth and Seventh Cranial Nerves in Plethodon Glutinosus, by PI. W. Norris 189 The Relative Prequency of Arterio Sclerosis of the Various Arteries, by W. E. Sanders 193 The Summer Resident Birds of Polk County, Iowa, by Lester P. Pagen. . . . 197 The Migration of Nervous Elements into the Dorsal and Ventral Nerve- Roots of Embryos of the Pig, by Albert Kuntz 217 Some Observations on the Embryology of Chironomus, by W. N. Craven. ... 221 PROCEEDINGS OF THE Twenty-Third Annual Session of the Iowa Academy of Science The meetings of the Twenty-third Annual Session of the Iowa Academy of Science were held at the State University, Iowa City, in room 107, Natural Science Building, on April 30 and May 1, 1909. In the business meetings the following matters of general interest were pre- sented: REPORT OF THE SECRETARY. To the Members of the Iowa Academy of Science: The twenty-second annual meeting of the Iowa Academy of Science was held at Iowa State Normal School, Cedar Falls, on May 1 and 2, 1908. The following fellows and members were in attendance: Messrs. Almy, Arey, Bailey, Bates, Bartholomew, Begeman, Bennett, Cable, Calvin, Chapman, Crawford, Guthe, Hersey, Jenner, Kay, Kinney, Morehouse, Newton, Nutting, Page, Pammel, Rock- wood, Ross, Shimek, Smith, Stookey, Summers, Tilton, Walters, Wheat, Wilson, making a total attendance of thirty-one. On Friday evening, May 1st, Professor John L. Tilton, gave th^ president’s address on “Science Required for a General Education.” Because of physical condition. Professor T. C. Chamberlain who was expected to give the evening lecture, found it necessary to send his co-worker. Professor Moulton, who gave an address on “Old and New Theories on the Formation of the Barth.” The membership of the Academy is slowly increasing. Four names were added to the list of fellows, and twelve to the list of members. This is not as large an increase in membership as in the preceding year. It has been some time since names were added to the Academy Council. At the last meeting fourteen members of the council were in attendance. The secretary recom- mends the increase of the size of the council. An amendment to the constitu- tion was proposed instituting a life membership. According to instruction the secretary sent due notice of the proposed amendment to the fellows of the Academy. A recommendation was adopted with reference to the awarding of an annual prize for meritorious scientific research work done in Iowa. Arrange- ment for the awarding of the prize was left to the executive committee. Letters were sent to the members of the committee and the replies received were at such variance that the secretary at once abandoned the hope of formulating 1 2 IOWA ACADEMY OF SCIENCE any practicable method of awarding a prize. Two members expressed them- selves as unfavorable to the idea of a prize, two suggested tentative plans and the others thought the task almost hopeless. Hence no plan for the awarding of a prize is reported. Section 4 of the constitution reads as follows: “An entrance fee of $3.00 shall be required of each fellow, and an annual fee of $1.00 due at each annual meeting after his election. Fellows in arrears for two years, and failing to respond to notification from the treasurer, shall be dropped from the Academy roll.” Since the associate members have the same privileges as the fellows with reference to the publications, it seems as though the constitution should provide for the payment of fees of some amount by such members. It is not necessary to call the attention of the Academy to the fact that the publication of Volume XV of the proceedings was delayed. Sometimes it is impossible for an author to read and return proof promptly, and occasionally such delays are sufficiently great that work considered more pressing by the printer demands and receives attention, thus interfering with work upon the proceedings. It will expedite matters much if all authors will find it possible to return proof immediately upon receiving it. The state printer thinks nothing need interfere with his work on Volume XVI during the coming summer. There is a healthy interest manifest on the part of the Academy in the work that is being done. Scientists not connected with the Academy seem to recoguize its value. More requests than usual have been received during the year for reprints and for volumes of the proceedings. The Academy is accom- plishing the purpose of its existence. A commendable result other than the purely scientific is being realized; that is, the development of the feeling of fellowship among the scientists of the state. This alone, if no other results were obtained, would justify the existence of the Academy. Respectfully submitted, L. S. Ross, Secretary. REPORT OF THE COMMITTEE ON MEMBERSHIP. NAMES PEOPOSED FOR FELLOWS. O. .1. Fay, Des Moines; Laenas G. Weld, Iowa City; E. B. Watson, Ames. Transferred from members, H. S. Fawcett, Gainesville, Fla.; Clarence D. Learn, Clermont; C. E. Seashore, Iowa City. NAMES PROPOSED FOR MEMBERS. Bert Gose, Pleasantyille; L. D. Weld, Cedar Rapids; Ellis B. Stauffer, State Center; Miss Elda Kemp, Marion; E. O. Heuse, Fayette; Thompson Van Hyning, Des Moines; B. O. Wolden, Wallingford; Miss Ada Hayden, Ames; Royal E. Jeffs, Ames; Lester P. Fagen, Des Moines; A. S. Begg, Des Moines; Harry R. Woodrow, Des Moines; Mrs. Gertrude B. Phillips, Grinnell; John T. Buchholz, Mt. Pleasant; Fred A. Fish, Ames; Samuel W. Griser, Independence; Joseph H. Neff, Fayette; J. W. Robinson, Grand River; Jesse A. Baker, Indianola; Albert Kuntz, Iowa City; R. S. Webster, Ames; Miss Florence Richardson, Des Moines. IOWA ACADEMY OP SCIENCE 3 AMENDMENT TO THE CONSTITUTION. The following proposed amendment was presented to the Academy in due form and was adopted. Insert after section 3, (4) “life members chosen from fellows.” In section 4, after the words, “his election,” “a person may become a life member on the payment of $7.00 after his election as a fellow, the transfer to he made by the treasurer.” “That said life membership fees be invested and only the interest of the same be used for current expenses of the Academy.” The follov/ing by-law w^as adopted at the meeting of 1907. “That hereafter a committee on membership be appointed by the incoming president at the meeting at which he is elected, which committee shall serve until their successors are appointed.” TREASURER’S REPORT. EECEIPTS. Cash on hand, April 30, 1908 $174.83 Dues and initiation fees 150.90 Sale of proceedings 9.96 Interest on deposits 8.08 — $343.77 EXPENDITURES. Expenses of lecture, 22d meeting $ 30.00 Progra,ms of 22d meeting 3.00 Binding, reprints, etc.. Proceedings of 21st meeting 68.35 Postage and incidental expenses of secretary 16.57 Honorarium of secretary 25.00 Cash on hand, April 30, 1909 200.85 — $343.77 Respectfully submitted, H. E. Summers, Treasurer. OFFICERS FOR TPIE YEAR 1909-10. President First Vice-President . . t^econd Vice-President Secretary Treasurer executive committee. Ecc-officio. .Frank F. Aemy, G. L. Houser, A. C. Page, L. S. Ross, George F. Kay Elective Samuel Calvin, N. Knight, C. O. Bates Frank F. Almy . . . G. L. Houser j^. C. Page L. S. Ross .George F. Kay 4 IOWA ACADEMY OF SCIENCE PROGRAM OF THE IOWA ACADEMY OF SCIENCE. The President’s address, by Professor Samuel Calvin, on “The Work of the Iowa Geological Survey,” and the lecture by Professor William A. Locy on “The Service of Zoology to Intellectual Progress,” were given in the Physics Lecture room at 7:30 p. m. Friday. Before the beginning of the evening program Pro- fessor Seashore gave demonstrations of the “Tonoscope” in his laboratory. PROGRAM. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. In Physics Lecture Room, 1:30 P. M., Friday, April 30th. Comet C 1908 (Morehouse) D. W. Morehouse The Asteroid, 1906, W. E. Ellis B. Stauffer Further Studies of the Eastern Nebraska Flora Charles E. Bessey The Polyporace^e of Fayette, Iowa Guy West Wilson Some Parasitic Polyporaceae ..C. D. Learn An Anatomical Study of the Roots and Rhizomes of a Few Weeds. . . . L. H. Pammel and Estelle D. Fogel The More Important Factors Concerned in the Production of Plant Diseases L. H. Pammel and Charlotte M. King Plant Distribution in Iowa in Relation to Geologic Formations. . .B. Shimek The Sand-Dune Flora of Iowa B. Shimek The Flora of Iowa Rock Robert B. Wylie Notes on Spore Formation in Ulva Robert B. Wylie Slime Moulds of the Yosemite Thomas H. McBride Okoboji Laboratory (Short Talk) Thomas H. McBride Some Features of Iowa Ground Waters. II W. S. Hendrixson The Training of the Technical Chemist (read on invitation) . .J. S. Staudt The Influence of Copious Ingestion of Water (read on invitation).... Stella A. Hartzell The Estimation of Arsenic and Cobalt in Smaltite Nicholas Knight An Analysis of the Fruit of Viburnum Nudum Nicholas Knight The Action of Manure on a Certain Iowa Soil E. B. Y/atson Signiflcance of Thrust-Planes in the Great Basin Ranges . . Charles R. Keyes Orotaxial Correlation of Geologic Terranes and Diastrophism Charles R. Keyes Carbonic Column of the Rio Grande Region Charles R. Keyes A Hysteresis Curve D. W. Morehouse and Harry Woodrow The Googler Primary Cell Harry Woodrow On the Use of the Balance LeRoy D. Weld The Fifth and Seventh Cranial Nerves of Plethodon Glutinosus H. W. Norris Hydroids as Ornamental Plants C. C. Nutting Arterio-Sclerosis W. E. Sanders Birds of Polk County, Iowa Lester P. Fagen The Migration of Nervous Elements into the Dorsal and Ventral Nerve- Roots of Pig-Embryos (Introduced by Prof. Gilbert L. Houser) Albert Kuntz The Unios of the Muscatine County Loess B. Shimek Some Observations on the Embryology of Chironomus W. N. Craven Darwin IOWA ACADEMY OF SCIENCE 5 RESOLUTIONS ON DARWIN. It is fitting that the Iowa Academy of Science should, in some way, spread on the minutes of its proceedings, its estimate of what science owes to the work of Charles Darwin; the centenary ■ of whose birth occurred on the 12th of February, 1909. Darwin’s contribution to science was two-fold; in the first place it consisted of additions, the result of research, additions made directly to the body of the knowledge of his time; secondly, it consisted in a singular impulse to natural history study, an impulse destined to be long-lasting as science itself. He possessed that singular breadth of mind and view that enabled him to look upon all nature as one; at least in the fascinating interest attaching to her wondrous operations; but in this very comprehensiveness, his mind became possessed at last by one idea, a universality, diflicult for some men yet to understand. He turned from one department of the natural world to another with an eagerness and apprehension absolutely impartial. To him all things were plastic. The world-shaping coral reefs rested not, but were by him asso- ciated with the phenomena of life; the barnacles or cirripeds were interesting to him not in themselves alone, but because of their wonderful departure from the habits of all their kin in adaptations almost unparalleled. All familiar domestic plants and animals charmed him by their pliancy, their obedience to the will of man; until at last there rose upon his vision the movement of the whole living world, the absolute rhythm with which all living things keep step to the changes of time and chance. Even the continents and islands, rising and dipping light on the waters, proclaim obedience to the self-same laws which guide the thistle-down in its airy flight across the sun-lit fields, or poise the humming bird in gauzy equilibrium before a summer flower. When he reached that view, geology, zoology, botany, lost their boundaries while the child of nature followed everywhere one shining silken clue which bound for him all things present and all things past in one unfailing and unbroken series. We are, accordingly, not surprised at the themes of Darwins books; the Volcanic Island, the Fossil Cirripeds, the Geology of South America, the Birds and Plants of the Galapagos, Domesticated Plants and Animals, the Origin of Species, the Fertilization of Orchids, Twining Plants. Even at the last, the insignificant earthworm became his theme; in the unrivalled comprehensive- ness of his scheme and vision, there is nothing great of earth, in Nature, noth- ing small. The men of this quiet day have small suspicion of the intellectual ferment of fifty years ago. The commercial excitement of these times does not com- pare with it. Had Darwin by some magic touch kindled a flame on the floor of every college, of every lecture-room, of every school house, of every church, in Chri^stendom he had not excited greater astonishment or more vigorous and wide-spread disputation. As early as March, 1860, Asa Gray, the foremost botanist of this country, was constrained to come to the defense of the author of the origin of species, his old-time correspondent and friend, by a series of papers which should allay the excitement of the country and the resentment of men who could not at all understand the position of the greatest naturalist among the sons of men. 6 IOWA ACADEMY OP SCIENCE Modern biologic study has brought forth a wealth of material, especially statistical or quantitative study of variations, experimental morphology and physiology, as the results of Darwin’s work. Some of these writers have endeavored to make light of Darwinism. New truths are added to the old and new evidences of the truth of Darwinism is being confirmed. Some phases of Darwinism are discredited but the theory of organic evolution is practically accepted by all working biologists. The theory of descent, though worked out, in part, by other naturalists before him, needed a Darwin to correlate the facts and marshal them together in order to construct a theory which would last as long as science should engage the attention of man. It was not a specu- lative philosophy put forth in his book on the origin of species, but one of the most remarkable scientific works ever published, his conclusions were based on sound principles and reasoning after a large number of observations had been made. In this way, the theory of descent came to be accepted by working naturalists. His work opened up a new field in biological research. No other scientific work perhaps so influenced the thought of his day or of our day as his epoch-making work on the “Origin of Species,” published in 1859. T. H. Macbeide, L. H. Pammel. W. N. Craven. ii IOWA ACADEMY OF SCIENCE 7 NECROLOGY. MR. W. N. CRAVEN. Mr. W. N. Craven, an Associate Member of the Iowa Academy of Sciences, was born near Indianola, Iowa, December 24, 1868. He was graduated from Simpson College in 1901. After three years of teaching in Iowa he was obliged by failing health to remove to Canon City, Colorado, where he resided till the time of his death, April 26, 1909. In 1903 Mr. Craven presented the accompanying thesis in connection with work at Simpson College. It was his intention' at the time to present the paper at a university later as an evidence of previous work when seeking admission to a graduate school, but his failing health soon necessitated a change in plans. His paper is now presented to the Academy partly in recognition of the quality of his work and partly that the results of his work may be of use to other students of biology. In the death of Mr. Craven Iowa has lost a young man whose marked ability, energy and purpose, gave promise of a useful scientific career. John L. Tilton. 8 IOWA ACADEMY OP SCIENCE DR. WILBERT EUGENE HARRIMAN. In 1896 Dr. Harriman became a fellow of the Iowa Academy of Science of which he has been a faithful member, though he never presented any papers, nor was it liis privilege to attend many of the meetings because of his profes- sional work. However, he was deeply interested in scientific subjects, especi- ally those connected in any way with the progress of medical science. He was born in Cherokee, Iowa, on December 4, 1871, and died in Hampton, Iowa, March 17, 1909. On his father’s side he came from a long line of New England ancestry, and on his mother’s side of Scotch and German ancestry. He gradu- ate(I from the Hampton High School in June, 1890, entering Iowa State College July, 1890, from which he was graduated with the degree of B. S. in November, 1893. He finished one year’s work in the medical department of the University of Iowa, where he won a prize in a competitive examination in histology. He studied medicine in the office of Dr. W. A. Rohlf, of Hampton, during the long winter vacations. He passed the medical examination of the State Board ana located in Gilbert, Story county. In 1894 he entered Jefferson Medical College, graduating in 1895. He also pursued work in the medical department of the University of Pennsylvania and later in the Post-graduate Medical College in Chicago. He was elected college physician and professor of histology, pathology and physiology, locating in Ames in 1895. To the great regret of the entire college community, he resigned his position as college physician on September 1, 1907, because of ill health, the board reluctantly accepting his resignation. He was a member of the State Medical Association and Fellow in the Amer- ican Academy of Medicine, and the Iowa Academy of Science. Papers pre- pared with care and skill were presented to some of the meetings of the Medi- cal Associations. He was esteemed and reported by his fellow practitioners as a worthy and able professional man. Dr. Harriman was a splendid type of citizen and the community irrespective of creed or party felt the loss to an unusual degree. In the class room he was concise, and no student ever left the room without feeling that some diffi- cult point had been made clear by his elucidation. The writer has many times heard words of praise spoken of his work as a lecturer and an expounder of the intricate problems of physiology and medicine. Dr. Harriman will, how- ever, be best known for service to the community and the college in particular as a physician and surgeon. During the epidemic of typhoid fever in 1900 he showed his unusual ability to cope with existing conditions and to place sani- tary conditions on a better basis. He worked night and day and earned the everlasting gratitude of a large body of students and the> faculty. It was my pleasure to have been associated with him in tracing the cause of this typhoid epidemic. He spared neither time nor effort to correct the conditions and Dr. Harriman. t> IOWA ACADEMY OF SCIENCE 9 suggest changes essential for the health of the student body. It was at his suggestion, a few years later, that a systematic study was made of the water and milk supply of the college. He was ever urgent for a sewage disposal system and good water supply. In this day of specialization the “family doctor” is almost a thing of the past, but the doctor was not only true to his calling as a surgeon but a good “Family Doctor.” He knew all about the members of the family and what they needed to restore them to health. It was not always medicine they needed. The patient felt that he was safe in his hands. That he had the confidence is shown in tne fact that his office was always filled with patients waiting for him. To all it was the same kind word and treatment. No matter what time of the day he was ready to serve his fellow men. It can be truly said that he offered his own life for the good of others. So conscientious was he in his work that when a patient had a . serious sickness he never left him until he was certain that the patient was on the road to recovery. No matter in what circumstances the patient was, he re- ceived the same treatment. This he considered to be the duty of a physician. It was his great interest in the student that commended him to every one in this community. There were stated hours in which the students could see the doctor, at the College Hospital, but they came to his office and called on him at all hours of the day and night. He was always ready to help them and in this way avoided many serious troubles. His sensitive nature and conscientious scruples made him more than careful in his medical work. His diagnosis was carefully made and consequently few errors in treatment. I had many talks with him, and he frequently un- bosomed himself in his frank and straightforward way about many subjects we had in common. He had a profound reverence for authority and felt deeply chagrined when an injustice was done to some one. It was in this frank and straightforward way that he won the esteem and respect of his fellow men. I love to think of the good doctor as I saw him in his profes- sional work in his prime, and when he was a student in my classes in the early nineties. His work as a student was an inspiration to me and his fellow students. The last time I saw him his health had been undermined to such an extent that he said, “I will have to quit practice for a while,” but his message to me was cheering and full of hope. It was the same kindly greeting as in earlier days. I did not think it would be a parting message, but such it proved to be. We looked back over the years when he told me that he was anxious to prac- tice medicine in Ames and establish his name among good practitioners of the State and become a worthy member of our community. Though young in years the service he did to his fellow men was rich in blessings and full of fruition. His life was one of strict service to others. What more can be said of any man devoted to his work of helping humanity? It is blessed beyond measure and our words are inadequate to express our gratitude to the man who led an unostentatious life for the good of mankind. L. H. Pammel, A. C. Page, G. F. Kay. PRESIDENT’S ADDRESS. THE WORK OP THE IOWA GEOLOGICAL SURVEY. BY SAMUEL CALVIN. The present Geological Survey was organized in 1892. Before that time Iowa had had the honor and the distinction of being served in the office of State Geologist by that Nestor of American Geology and Paleontology, James Hall, and by his worthy successor. Dr. Charles A. White. It was Iowa’s great mis- fortune that neither of these distinguished geologists was permitted to do more than the merest reconnoissahce work. Official geological work in Iowa may indeed claim three distinguished names, for geological investigation began in this state under the direction of David Dale Owen, United States Geoolgist, in the autumn of 1839. Considering the limitations under which the earlier ge- ologists labored, the extent and accuracy of their observations are matters of constant surprise to their successors. All that was done, however, and all that could be done by the earlier geolo- gists, was to determine in a general way the age and characteristics of the geological formations which occurred within the state, and something of their surface distribution. Nothing like detailed work was possible. There was neither time nor opportunity to ascertain the limits of the minor divisions of the formations, nor could the zonal distribution of faunas be worked out; the geological resources of the state could be but dimly appreciated; approxima- tion only could be made to the boundary lines of the formational areas. The first great aim of the present Geological Survey was to make maps show- ing as accurately as conditions would permit the exact areas in which the several formations are exposed at the surface. In a country which, like Iowa, is deeply covered with glacial drift, the work of geological mapping is one of extreme difficulty. Even now, over large areas, it is impossible to do more than to draw lines where the few scattered outcrops indicate the boundaries should be found if the drift mantle were removed. The work has been pur- sued with the purpose of getting the nearest possible approximation to accuracy. The surface has been studied county by county, and the first studies were so distributed as to cover areas of strategic importance, areas in which contact lines, special formational characteristics, or geological products of commercial value were expected to occur. In the matter of the determination of forma- tional boundaries the results have been such as to make it possible to publish the large-scale geological map which was issued as part of Professor Wilder’s Report for 1905. A comparison of this with the geological maps of Iowa previously published will show what has been done in the direction of detailed mapping of Iowa’s geological formations. For seventy-five of the ninety-nine counties of the state geological maps have been published on a scale of half an inch to the mile, and the geological structure of these counties has been set out in detailed reports. County reports embrace all the information which may be collected by careful study of topography, drainage, building materials and (11) 12 IOWA ACADEMY OF SCIENCE other quarry products, clays, useful minerals, soils, sands and gravels which may he used in the improvement of roads or for other purposes, water sup- plies, possible water powers, and whatever else it may be of service for the people to know with respect to their natural resources. As a contribution to knowledge of great importance to the people of Iowa there was published, early in the history of the present Survey, a preliminary report on coal by Keyes. In this volume was assembled all the information relating to Iowa coals available at the date of publication. Special reports on the coal counties have since given greater precision to our knowledge of the subject; and the Survey has ready for the press a monograph on Iowa Coal which will place before the people all the facts which have been accumulating during the past ten or twelve years. The work on the coal monograph was begun by Professor Wilder while he occupied the position of State Geologist; his interest and efforts have been continued since large business affairs called him from the state; under his direction the field work and preparation of the manuscript for the volume has been carried forward by Henry Hinds and Assistant State Geologist Lees. The investigation of the peat deposits of the state and their possible use as a source of fuel supply has been completed under the direction of Dr. S. W. Beyer, and the manuscript is ready for the printer. To Dr. Beyer the Survey and the people of Iowa are indebted ior exhaustive and masterly reports on Clays and Clay Products, and on Quarry Products. These subjects are treated in volumes XIV and XvII of the Iowa Geological Reports. The work set out in these volumes has won recognition and high commendation from experts everywhere. As noted above, the report on peat, by Dr. Beyer, is ready for publication; and in the course of another year or two the same investigator ^^ill set before the people detailed information relative to roads and road material. The investigation of the resources of Iowa in the matter of underground waters suitable for municipal, domestic and medicinal uses has been in the hands of Professor Wm. H. Norton ever since the Survey was established. A preliminary report of great economic and scientific value was issued as part of volume VI, in the year 1897. The collection and classification of data have been continued without interruption since that report on water resources was published. The amount of material in hand is large and it is of the greatest importance. The Survey contemplates the early publication of a volume which will place before the people of the state full and trustworthy information on a subject of the utmost importance to their welfare. The gypsum deposits of Iowa have Fort Dodge as their center. Though limited to a small area, which probably does not exceed fifty square miles, these deposits have become the basis of a manufacturing industry of large propor- tions. The geology of the region was studied by Keyes, and later, in more minute detail, by Wilder. In his report on the geology of Webster county Wilder presents the results of very exhaustive investigation on the areal ex- tent, the thickness and the availability of the deposits as well as on the methods of mining, quarrying and manufacturing. He suggests additional uses for gypsum products and points out possible improvements in the methods of manufacture. The results of personal studies relating to the manufacture and uses of gypsum in France and Germany are incorporated in an Appendix to the Webster county report, and so there is placed before the manufacturers of lOWA ACADEMY OF SCIENCE 13 Iowa, in reliable form, a fund of useful information that should prove of the highest value in the further development of this important industry. The lead and zinc resources of the state have received deserved attention. Early in the history of the present Survey a full report on the mining industry around Dubuque was prepared by Leonard on the basis of extended investiga- tions made in the field, and was published in volume VI. Later, the subject was reinvestigated, and in greater detail, by Bain, and the results of this later work constitute the greater and the more important part of the report on the Geology of Dubuque county, which appears in volume X. The oldest of the rock formations native to Iowa, and the only deposit of pre-Cambrian age in the state, is the Sioux quartzite. This is limited to a small area in the extreme northwest corner . of Lyon county, but it is quite extensively developed northward and westward in Minnesota and South Dakota. This unique formation was deemed worthy of a special report, vs^hich, after careful field study, was prepared by Dr. Beyer. In spite of all that can be said and done, there are people in enlightened Iowa who persist in the erroneous notion that it is necessary only to bore deep enough to get supplies of petroleum and natural gas in any desired quantities in any locality. Many thousands of dollars have been uselessly expended in the search for these products in regions that had previously been explored with the drill in efforts to get supplies of water. The records of these drill holes were available, but the parties interested seem to have been possessed, or obsessed, by the curious notion that wells drilled through the geological forma- tions to get water prove nothing as to the presence of gas or oil. When you want water, drill for water; and when you want gas or oil, drill for gas or oil; as if the intent of the driller exercised some mysterious influence on the nature of the products to be obtained from the deeper-lying strata. The Survey has told the people the truth in all such cases and has conscientiously tried to get them to see it, but the truth has proved in most instances to be exceedingly unwelcome. Some have tried to ward off the unwelcome facts and compel the rocks of Iowa to yield products they do not possess by indulging in coarse abuse of the Survey and its officers, but the result has not been a pronounced success. The position of the Survey has been sustained in every case; it has nothing to apologize for, nothing to recant; it may be worthy of note, though in no way unexpected, that the loudest and coarsest of the vilifiers have never offered a single word of manly apology. The small amounts of gas from deposits of sand and gravel in the drift have been recognized since before the Survey began, and it is hoped that many more of these reservoirs may be found. Letts and Herndon are the best known localities .i^mong those where Pleistocene gas is known to exist. The deep wells, so widely distributed, have in general settled the question of oil or gas from the older geological horizons, but there yet remain a few unexplored areas that may some time surprise us by becoming productive. The work of the Survey is now far enough advanced to make it possible to construct a detailed section of the rocks of Iowa, fairly correct. Thin zonesr of economic or scientific importance have been determined and recognized, in some instances over hundred of square miles. For example, the non-mag- nesian, lithographic limestone which is the principal basis of the Portland cement industry at Mason City, has been traced from Iowa City to Howard and Mitchell counties and across the line into Minnesota. A reef of stromatoporoid 14 lOVv^A ACADEMY OF SCIENCE Morals, intimately related stratigrapliically to the lithographic beds, and of no small economic importance, has a geographic distribution equally extensive. Other well defined zones of the Devonian system are easily recognizable. To Norton we are indebted for the recognition and definition of the lower members of the Devonian, the Otis and the Coggan beds, which, however, are found only in the southern part of the Devonian area. Similar zones, definite and con- stant as to position and having great geological significance, have been deter- mined for the Niagaran limestones, for the various members of the Ordovician, for all of our geologic systems ranging from the Cambrian to the Upper Crea- taceous. The Iowa Geological Survey may be credited with some of the most important contributions yet made to our knowledge of Pleistocene geology. Before the Survey came into existence Chamberlin, Salisbury and McGee, by a series of masterly investigations, had determined the criteria which might be used in the differentiation of successive drift sheets and had pointed the way to the correct solution of Pleistocene problems. Three episodes of glaciation were recognized in a general way, and had been named by Chamberlin the Kansan, Iowan and Wisconsin, but the limits of these were only vaguely known. Bain, at that time Assistant State Geologist, demonstrated that the gravel beds at Afton Junction lay beneath the Kansan of Chamberlin, and that, below the gravels, there was an older drift sheet whose true geological position had been misunderstood. In this way a fourth glacial deposit took its true place in the Pleistocene series. This, although the fourth in the order of recognition, was in reality, so far as now known, the first in the order of time. It has not yet received its proper distinguishing geographic name, but is simply known as the pre-Kansan or sub-Aftonian. It has been exposed by the erosion of the stream in the valley of the Grand river a mile or two below Afton Junction, in the valley of the Little Sioux in the northern part of Harrison county, at the base of the Missouri river bluffs in Fremont and Mills counties and at other points in the southwestern part of the state; while eastward it shows in the Mississippi bluffs and lateral ravines near Muscatine. It has been seen in arti- ficial excavations as in the great Oelwein cut in Payette county; it is known to occur in many well sections; but there is no locality at present known where it is found as the surface drift. At all its exposures we see only the edge of the deposit, everywhere it is overlain by younger formations. We are indebted to Leverett for the last of the drift sheets to be recognized, the Illinoian. This, the fifth in order of recognition, is the third in order of chronological suces- sion. The Iowa Survey has worked out the margins of the several drift sheets, so far as the margins fall within the borders of the state; it has studied and described the differential structural Characters of the deposits ; it has noted and recorded the relative amounts of erosion, weathering and general altera- tion in the surface of the Kansan, Illinoian, Iowan and Wisconsin respectively, and, with proper caution, has used these as indices of the relative age of the formations; it has studied the interglacial deposits and has drawn conclusions concerning the interglacial faunas, floras and climates. The soils of Iowa con- stitute her most valuable geological endowment; over extended areas the fer- tility and adaptability of the soil varies with the nature of the underlying drift; there are alluvial soils, lacustrine soils, loess soils as well as soils of glacial origin; studies of the Pleistocene deposits are, in the highest sense, icontributions to Economic Geology. IOWA ACADEMY OF SCIENCE 15 Apart from the sheets of glacial drift, which constitute the most important of the Pleistocene deposits, whether viewed from the economic or the purely scientific side, the Survey has demonstrated the stratigraphic position and areal extent of interglacial and postglacial sands and gravels that may not he neglected. These are important not only as furnishing sands for use in build- ing, and gravels for the improvement of roads, hut with the multitudinous uses of cement in modern construction they attain an economic value not easily calculated. There are at least three well defined sand and gravel horizons in the Pleistocene; two are interglacial, one postglacial. Between the pre-Kansan and the Kansan drifts are extensive beds known as Aftonian, which, as recent work has demonstrated, are very extensively developed throughout southern, southwestern and western Iowa. Studies hy Shimek during the last field season have broadened our knowledge of the extent and distribution of these Aftonian beds, and when we remember that they occur in regions where there are few stone quarries and the modern streams fiow through mud fiats, without sand bars, the economic importance of the Aftonian sands and gravels may be appreciated. Great, however, as is their economic value, the purely scientific significance of the Aftonian beds is even greater. The Aftonian gravels, especially up and down the western slope, have been yielding remains of animals that flourished during the interglacial interval, while peat and soil beds of the same age are telling us of the forests and humbler plants that furnished shelter and food for the Aftonian fauna. The results of these Aftonian studies have not yet been published, but we are prepared to say that during Aftonian time Iowa supported three great elephants, ElepJias imperator, Elephas columdi and E. primigenius, one mastodon, Mammut americanum, at least one large camel, a large stag intermediate between the moose and the elk, and at least two species of horses. In addition to the bones and teeth of these great mammals the Af- tonian sands have furnished shells of river mollusks, identical, according to Shi- mek, with the species living in our modern streams. The Aftonian climate was not very different from that experienced by modern Iowa. The important and significant result of these discoveries in western Iowa lies in the fact that for the first time, the exact horizons of the Equus and ElepJias imperator beds has been definitely fixed. These same great mammals have been found in Pleistocene deposits in western Nebraska, in Texas, in Oklahoma, and in other regions which were not covered v/ith glacial drift; but the precise position of the beds, stratigraphically, could not be determined. The work in Iowa gives us an un- doubted, definite horizon. The studies in Iowa further demonstrate that the Aftonian was a real interglacial interval, that its deposits do not represent a mere “fluctuation and temporary local withdrawal of the pre-Kansan ice” as some with meager and partial, knowledge of the subject are disposed to insist. The Aftonian, as w^e now see it, was a time when extensive grassy plains alternated with luxuriant forests, a time when soils were developed, when?, great peat beds accumulated, when heavy rains fell and swollen rivers fre- quently overflowed their flood plains, when this latitude had a climate whichi permitted the modern types of mollusks to occupy the streams and when great herbivores found an abundance of food on the open plains, in the warmer river valleys, or over the thinly wooded slopes. There is another interglacial interval between the Kansan and the Illinoian stages of ice invasion, the records of which have been determined by Leverett 16 IOWA ACADEMY OF SCIENCE of the United States Geological Survey. Near Yarmouth in Des Moines county, soil and peat belonging to this horizon are well developed, and these have furnished remains of at least two types belonging to the recent fauna, the wood rabbit and the skunk. Between the Aftonian and the Yarmouth changes in the life of the continent had taken place, hut our knowledge of the Yarmouth deposits and the fossil mammals they contain is as yet too meager to enable us to say how great the changes were. Extensive beds of gravel, ' probably representing the beginning of the Yar- mouth interval, were deposited by floods at the time the Kansan ice was melt- ing. These have been called the Buchanan gravels. They attain their best development in the northeastern counties of the. state, but they are known as far south as Iowa City, and they have furnished enormous quantities of rail- way ballast near Leroy in Minnesota. For railway ballast, for the improvement of village streets and country roads, for all grades and phases of cement con- struction, for ordinary building sands, the Buchanan gravels so generally dis- tributed in Delaware, Buchanan and other northeastern counties as to be con- veniently available in almost every neighborhood, furnish ideal materials prac- tically inexhaustible. For reasons easily understood and fully set out in some of the reports the Buchanan gravels occur on the uplands as well as in what were sags and valleys in the ice moulded surface of the Kansan drift, and it is to this fact that we owe their presence in almost every neighborhood, no matter where located. There are some beds of rather fine, stratified sand distributed along the stream valleys which originate in the Iowan plain, referable to the relatively meager floods which resulted from the melting of the Iowan ice. The deposits are unimportant commercially, but they help to illuminate and unify the com- plex history of the Pleistocene period, and every phase of this history is of the utmost importance to the inhabitants of Iowa. As the work of the Survey has conclusively demonstrated, the gravels depos- ited in connection with the melting of the Wisconsin ice, at the very dawn of postglacial time, are by far the most extensive of all the Pleistocene deposits of similar character and origin. In the north-central counties of the state great sheets of gravel cover areas equal to entire townships, while gravel kames and eskers are distributed as conspicuous knobs and ridges over much of the sur- face embraced in the Wisconsin area. These gravel ridges culminate in Ochey- edan Mound in Osceola county, a great kame rising 100 feet above the surround- ing prairie, keeping watch over a radius of twenty-five miles or more, its summit well worthy of the distinction which it reputedly holds of being the highest point of land in Iowa. For detailed studies of the Wisconsin drift, of the associated sheets and ridges of gravel, and of the characteristics and geographic position of the Altamont moraine on the western side of the Wisconsin lobe, the Survey is indebted to the painstaking work of Professor Macbride. Iowa is rich in its possessions of another Pleistocene deposit of incalculable economic importance, the Loess. No subject has been more misunderstood, no subject has given rise to more uselss and meaningless controversy, no subject has been responsible for more grotesque and untenable hypotheses as to its origin and original distribution, than the Loess. Iowa offers unsurpassed op- portunities for the study of this remarkable geological deposit, and an Iowan who has given some time in recent years to Survey work, but who had critically ^studied thousands of loess sections years before the Survey was organized, has IOWA ACADEMY OF SCIENCE 17 marshalled the arguments and the facts in favor of the eolian origin of loess so convincingly that his views are now generally accepted by leading geologists everywhere. Professor Shimek was attracted to the loess by his interest in the life, habits and distribution of land snails which he had studied more patiently and exhaustively than probably any other living naturalist. The loess is very generally fossiliferous, and practically all of its fossils are shells of terristrial mollusks. These fossils bear conclusive evidence of having been buried where the creatures lived and died. Professor Shimek has driven home the argument that no theory of loess origin is tenable that does not satisfac- torily account for the presence and distribution of its fossil land snails. The loess fossils throw light on the humidity and temperature of the atmosphere and on the distribution of plants at the time the loess was forming. The loess and its fauna and all the economic, geologic, meteorologic and botanic problems connected with it will be the subject of a monograph, now in preparation by Shimek, which will soon appear as one of the volumes of the Iowa Geological Reports. Among the more distinctive contributions made by the Survey to pure science attention may be called to the discovery of the great Devonian fish bed in the State Quarry limestone near North Liberty. The fishes from the State Qdarry bed, together with other Devonian fishes from Iowa, have been studied by the scholarly master of this branch of Paleontology, Dr. Charles R. Eastman of Harvard, and his report has been recently published as volume XVIII of our current series. As shown by this report, the new fish bed has furnished a number of genera and 'species at present unknown elsewhere in the world. Some of these new forms illuminate in interesting ways the history of fish development and bring to our knowledge ancestral phases of certain groups which have long been known to students of science. Among other contributions to pure science we may note that the Survey has brought order out of the apparently hopeless confusion which previously existed relative to the limits, distribution and characteristics of the Galena and so- called Trenton limestones; it has shown that no representatives of the lower Devonian occur in our geological column, only late Middle, and part of the Upper Devonian being present; it has proved the great overlap and unconform- ity in the northern part of the state whereby comparatively late Devonian has been brought to rest on eroded Ordovician, with the consequent apparent thinning and complete disappearance of the Niagara in that direction; the definite life zones of the various rock systems from Cambrian to Carboniferous have been worked out with a fair degree of thoroughness; the true correlation of the Iowa Cretaceous has been ascertained; and the characteristics, thickness and distribution of the earlier beds underneath younger formations have been studied, and mapped in connection with Norton’s work on deep wells. Precise and definite knowledge of every sort and kind has a value that it is difficult to express in the standard units making up the currency of commerce. It has been the aim of the Survey to collect and furnish trustworthy informa- tion, the fullest possible, relative to the geologic structure and geologic re- sources of Iowa; but while the purely economic side of the subject has neces- sarily been emphasized more or less in all the work so far done, any facts that could make knowledge clearer, broader, more definite, have not been neglected. 2 18 IOWA ACADEMY OF SCIENCE Facts that seem at first to he in no way related to commercial or industrial ac- tivities, may be the germs from v/hich will spring some great body of knowl- edge of the utmost importance to the well being of mankind. The oft quoted example of the twitching of the muscles in the legs of a frog under an elec- trical stimulus seemed as far removed as possible from anything that might contribute to the accumulation of wealth or the promotion of human comfort, and yet that simple fact was the starting point from which have developed the marvelous uses and applications of electricity which are of such stupendous and daily growing importance in modern human life. The pure science of today becomes the basis of the applied science of to-morrow, and enlightened states, the world over, realize that money expended for the prosecution and encouragement of scientific research, is money well invested. By the substitu- tion of definite knowledge for vague uncertainty relative to water supplies, coal, lead and zinc ores, oil, gas, Portland cement materials, clays and all other natural products, the Survey has saved to the citizens of Iowa, many times over, all that the Survey has cost. As an aid to public education, helping the people to see and appreciate and correctly interpret the geological phenomena which lie all about them, helping them to view the world in which they live understandingly, instead of looking at it with the vague, dull, comprehensionless mental attitude of the unlearned savage, the Iowa Geological Survey has earned its place as an important factor in contributing to the general intelligence of this most beautiful, most pros- perous, most intelligent state. THE POLYPORACEAE OP PAYETTE, IOWA. BY GUY WEST WILSON. The Polyporaceae are a group of most interesting fungi which have of recent years assumed a position of prime economic importance as it has been demon- strated that many of them cause the decay of timber trees which formerly they were supposed to follow. The parasitic nature of these fungi has added a new incentive to their careful study. Some species are found only on the diseased portion of living trees, while others appear to inhabit only dead timber. Of these it is not improbable that a considerable number may be able to infect living timber and later to maintain themselves on the wood as long as those portions remain which furnish them with their food. ' The present paper embodies the field observations upon species of this family in the vicinity of Payette. Whilst the list can lay no claim to be other than a preliminary paper, several species are recorded as parasites which are not so indicated by Dr. Murrill in his monograph of the family,* while others are of interest because of the extension of their range. The majority of the ‘species have been sent to Dr. Murrill for verification. The nomenclature of his monograph, which is .the only comprehensive treatment of the American species, has been followed and such synonyms added as were necessary to cor- relate the list with other publications on Iowa Polyporaceae. 1. Hydnopoeia euscescens (Schw.) Murrill. {Irpex cinnamomeus Pries.) This species, which at maturity has the appearance of a resupinate Hydnum, is very common on various oaks. If the tree is still upright the entire surface may be covered; but on fallen branches only the lower portion is affected, giv- ing quite a varied appearance to the fungus. -2. PoMiTiPOEiA OBLiQuiFOEMis Murrill. The present species was described from material collected on hard wood logs near Cincinnati, Ohio, and is also recorded from Pennsylvania. In our territory it occurs both as a parasite and a saprophyte. It has been collected several times from wounds on oak and Mr. Learn has found it on Populus grandidentata in the northern portion of the ^county. 3. Iepicipoeus lacteus (Pries) Murrill. {Irpex TuUpiferae (Schw.) Pries.) Common on dead and living wood of various species. While usually con- sidered a saprophyte this species is a true parasite on various species of wild and cultivated Prunaceae. Several cherry orchards in the vicinity, and numer- ous examples of the wild cherry have been noted as having succumbed to the ravages of this species. One orchard in particular was noted which has been almost depleted by the present species in company with Coriolus proUflcans *N. Am. Flora, Vol. pts. 1 and 2. (19) 20 IOWA ACADEMY OF SCIENCE and Hapalopilus gilvus. The additional hosts noted locally are Rhus glabra, Populus grandidentata and. various oaks. 4. PoEONiDULus coNCHiFER (Schw.) Murrill. (Polyporus conchifer Schw., Polystictus conchifer Schw.) Common on fallen twigs of the elm. (Ulmus americana). 5. CoRiOLus VERSICOLOR (L.) Quel. {Polyporus versicolor (L.) Fries), Poly- stictus versicolor (Fries.) This beautiful species is common on almost all our forest trees and shrubs. It is one of our worst forest pests and often invades the orchard and ornamental plantations. It causes a serious disease of the lilac and affects the wild grape. 6. CoRioLus NOGROMARGiNATus (Schw.) Murrill. {Polyporus hirsutus Fries, Polystictus pergamiuus Fries.) Common and variable, on numerous species of dead wood. 7. CoRioLus PROLiFiCANS (Fries) Murrill. {Polyporus pergamenus Fries, Polystictus pergaminus Fries.) Very common both as a parasite and saprophyte on Quercus, Betula, Populus, and less frequently on other trees. 8. CoRioLELLus SEPiuM (Berk.) Murrill. {Trametes sepium Berk.) Not common, on dead oak both in the forest and in structural work. 9. Tyromyces semipeliatus (Peck) Murrill. {Polypurus semipeliatus Peck.) Rare on Salix, upon which it is a wound parasite, gaining entrance through dead branches. 10. Spongipellis unicoloe (Schw.) Murrill. {Polyporus obtusus Berk.) This handsome species is not uncommon on oak saplings throughout the. county. It is a wound parasite. 11. Spongipellis occidentalis Murrill. This species, originally described from specimens collected on beech {Fagus), has been previously reported only from New York. A fine specimen was found on a wound of a trunk of Ulmus americana in Fayette. The species is quite distinct from the preceding, which it resembles in being a wound parasite. The denser pelius, smaller pores, and the brittleness of the later upon drying easily separate it from the former species. 12. Bjerkandera adusta (Wind.) Karst. {Polyporus adustus Fries.) A common and variable species which may be either a true parasite or a saprophyte. The light colored, imbricate pelius and smoke colored hymenium easily separate this species. I have found it on erect trunks grading into a pseudo resupinate form which at first would never be taken for this species. Common on oak, basswood, birch, etc. 13. Bjerkandera fumosa (Pers.) Karst. {Polyporus fumusus Fries). Much larger and with a lighter colored .hymenium than the preceding species. A single collection was made near Fayette on an old elm log. 14. Hexagonia alveolaris (DC.) Murrill. {Favolus europeaeus Fries). Very common on fallen branches and dead twigs of various trees. 15. Polyporus arcularius (Batch) Fries. Common on fallen twigs, buried roots, and stumps of deciduous trees. The species is quite variable, although easily recognized by the alveolar pores, ciliated margin and palid pelius, a combination of characters unique among the northern species of the genus. IOWA ACADEMY OF SCIENCE 21 16. Polyporus fissus Berk. A very large and conspicuous species which has been collected but once in the vicinity of Payette. The specimens were growing on a badly decayed log, probably elm. 17. Geieola frondosa (Dicks.) S. P. Gray. {Polyporus frondosus Fries). A very beautiful species which has been collected once in humis at the base of an oak, near Payette. 18. Pycnoporus cinnabaeinus (Jacq.) Karst. {Trametes cinnabarina Fries, Polystictus cinnabarinus Pries). A very conspicuous species easily recognized by its bright color. Fairly abundant on fallen wild cherry. 19. Laetipoeus speciosus (Batt.) Murrill-. {Polyporus sulphurous Fries, P. cincinnatus Morgan). Quite common on various living and dead trees, especially oak, ash, and wild cherry. This is the only edible species of the family, at least in so far as local flora is concerned. 20. Fun ALIA stuppea (Berk.) Murrill. {Trametes PecTcii Klachb). A very distinct species, easily recognized by its hirsute pileus and large very irregular pores. Not uncommon on poplar. 21. Hapalopilus gilvus (Schw.) Murrill. {Polyporus gilvus Schw). A very common and rather constant species which is easily recognized by its Arm sporophore which is of a yellovv^ish or brownish tint. The individual sporophores are either scattered or imbricate and are produced in great abundance, much to the injury of our forests. The worst sufferer from its depridations is the oak. Various other trees are infected to a certain extent, among these being the cultivated cherry. 22. Ischnodeema fulginosus (Scop.) Murrill. {Polyporus resinosus Pries). Common on dead wood, especially of the linden and red maple. 23. Pomes roseus (Alb. &. Schw.) Cooke. On structural pine, Clermont, (C. D. Learn.) The rose colored sporophore easily distinguishes this from our other species. 24. Pomes feaxineus (Bull.) Cooke. Not common on Fraxinus. Collected at Clermont and Fayette by C. D. Learn. 25. POMES’ ohiensis (Berk.) Murrill. {Trametes ohiensis Berk). Rare on oak posts. 26. Pomes populinus (Schum.) Cooke. This species does not appear to be very common as it has been collected only two or three times. It is parasitic on Acer skccharinum and A. saccharum. 27. Pyropolyporus ignarius (L.) Murrill. {Pomes ignarius Gill., F. nigri- cans Gill). This is one of our commonest and most variable species of pasitic polypores. It causes no end of damage to certain of our forest trees. Two forms are recognizable; the first, or typical form, has the hymenium brown, the surface less rimose than in the second, and is more broadly shelving in habit; the other form being narrower and more nearly hoof-shaped, with a bluish hyme- nium. This is Fomes nigricans, which upon first acquaintance appears distinct enough to warrant its recognition as a distinct species. A collection made by 22 IOWA ACADEMY OP SCIENCE Mr. Learn near Clermont makes this treatment of the forms impossible as the habit is that of F. nigricans; but with the brown hymenium of the typical form. At most these can be ranked only as varieties. The typical form is a wound parasite on Juglans cinerea and Ostrya virginica, while the other form is confined to PopuUis. 28. Pysopoluporus fulvus (Scop.) Murrill. {Femes fulvus Gill). Very common on the wild plum, destroying entire thickets, and sparingly on cultivated plums of American and European varieties. 29. Pyeopolyporus Everhabtii (Ellis & Gall.) Burrill. {Mucorniporus Everhartii Ellis & Gall., Femes rimesus and F. ignarius Aut. p. p.) This is a very common parasitic species, often reaching a large size. It is parasitic on various species of Quercus. 30. Pyeopolyporus conchatus (Pors.) Murrill. Very common about Payette. This is a very variable species, either peliate or resupinate, and in peliate forms often moss covered. The velvety fawn or light brown margin is quite characteristic. Very common as a parasite on Grategus, wild grape, ash, and as a saprophyte upon various species of deciduous wood. 31. Elfvingia fomentaria (L.) Murrill. {Femes fementarius Gill). A specimen from Betula papyrifera is in the collection of Upper Iowa Uni- versity. 32. Elfvingia lobata (Schw.) Murrill. {Femes renifermis Morgan). Not rare on dead deciduous wood. This species is an annual, the pelei becom- ing imbricate. It is easily distinguished from the following by this character and its smaller size. 33. Elfvingia megaloma (Lev.) Murrill. {Femes applanatus of American authors). Very common both as a parasitic and saprophyte on various deciduous trees. 34. Cereena unicoloe (Bull.) Murrill. {Daedalea nniceler Pries). A very common saprophyte on various species of deciduous wood. It is easily mistaken for a Cerielus from which it differs in the daedaleoid pores. 35. Daedalea confeagosa (Bolt.) Pers. Very common both as a parasite and saprophyte on Salix and Grategus. 36. Lenzites betulins (L.) Pries. Very common on oak and rare on birch. 37. Lenzites odora “Aut.” A poorly understood species of uncertain affinities. Common on railroad ties and structural timber. 38. Gleophyllum trabeum (Pers.) Murrill. Common oh fallen timber. SOME PARASITIC POLYPORACEAE. BY CLARENCE D. LEARN. Up to within the past eight or ten years, very little attention had been paid in America to the study of those forms of fungi causing forest diseases. The reasons are obvious. Previously, the occurrence of a few diseased trees was practically unnoticed, due to the vast area of our forests. But, with the ad- vance of the lumberman in the last decade, the situation has changed, and a demand has arisen among all classes of people for a more economical and rational treatment of the existing forest lands. The diseased trees of the primeval forest were ignored, as they were so few in comparison with the sound ones. While now the marked appreciation in the value of timber, cause the timber destroying agencies to become of immediate interest. These silent enemies of the forest are working here and there, not 'attracting the attention of the casual observer as do the careless habits of the lumberman and the forest fires. The polypores were formerly supposed not to be of a parasitic nature, and the papers published upon them dealt only with the fruiting portion. While now their parasitic nature is established. The effect brought about through the growth of the fungus, is the important economic question which is con- sidered in the present paper. The field for work on forest diseases is a large one, and its possibilities are just becoming apparent. Compared with other fields of activity, there are but a few workers, among the more prominent of whom we might name Drs. von Schrenk, Spaulding, Metcalf, Hedgecock, and Professor Atkinson. The govern- ment is just beginning to take cognizance of these fungi as producing diseases of forest, nut, and shade trees as is shown by Orton and Ames in Plant Diseases in 1907, where mention of them is made forty-eight times. In the present paper, I shall present a study of some of the higher fungi of the family Polyporaceae, and describe the characteristic changes which their mycelia induce in the wood of the trees in which they grow. These fungi were observed in the field causing the decay ascribed to them. The relation of the fungus to its host is a definite one. The question of the spore gaining its entrance is somewhat problematic. That any here studied gained entrance unaided, I believe is not safe to assert. Few of the fungi can gain an entrance unaided through the living layer of cambium tissue, which envelopes the entire tree, and while uninjured, serves as an effectual barrier against many of these enemies. For their entrance, fungi are usually de- pendent upon some agencies, usually gaining entrance through mechanical injuries to the host. There must be some condition conducive to infection, either a broken branch, a wound, or lack of vitality. When a tree once be- comes diseased, the mycelial threads spread rapidly, filling the heart wood with (23) 24 IOWA ACADEMY OF SCIENCE holes or changing it to a brittle substance having none of the properties of wood. These changes weaken the trunk, and now it is only a question of time until the tree is broken by the wind. That some fungi possess great adaptability is shown by Elfvingia megaloma, which attacks both living and dead trees, as well as stumps and logs, showing it to be both parasitic and saprophytic. Pyropolyporus conchatus also has this dual nature. The greater majority of parasitic diseases, however, is induced by a wound. As stated before, in most instances there must be some means for the spore to gain access other than directly through the cambium layer. Hence if it be true that injury is necessary for infection, we might decrease the pos^ sibility of attack by care in handling trees to be transplanted, in pruning, and also in protection. The true parasite is not to be found among the specimens under consideration in this paper. Very few wood rotting fungi are capable of entering an uninjured tree. Nearly all gain lodgement in wounds, grow in from these, and rot the wood. The effect of parasite on the host may remain unnoticed for some time, as the growth is very slow. The first noticeable indication of . the presence of a fungus disease is the sporophore. As the age of the fungus increases the greater is the number of sporophores, of which I have seen as many as twenty- five on a single host. When this stage is reached, the effect may be noticed in the dead branches at the top, and pale color of foliage. When the host becomes thus infected it succumbs to the wind by either being broken off or up-rooted. A microscopic examination of some of these diseases shows that the wood tissues are penetrated by tiny mycelial threads. These threads are seen to attach themselves to the cell walls, and to pierce it in all directions. Thus these tiny threads form a network in the wood, and as they increase in number, they dissolve the walls of the wood cells converting them into food for their own consumption. In some cases it is the woody cell wall alone that is attacked; in other cases they consume the starch found in the cells; but in all cases of decay we find these mycelial threads are responsible for the mischief. These fine threads are the vegetative body of the fungus, the little shelf its fruiting body, on which it produces myriads of tiny spores. The economic side of the problem is also worthy of our consideration. We find that there are but a very few kind of trees, if any at all, that are not sub- ject to fungus diseases; and that both dead and living trees are attacked. A tree does not lie on the ground any time until it is nearly covered with fungus growth. If one is to realize any value from diseased trees they must be used before they reach the last stage, or before they fall. Some of these diseases affect the heart wood, rendering it useless for lumber, and . of little value as fuel. That this problem is of the greatest importance is evidenced by the attitude of the government in studying its character, and trying to determine some means of prevention. The species discussed in this paper are the most characteristic and common of this region, infesting our chief forest trees. They are Pyropolyporus ignior rius (L.) Murrill; Pyropolyporus Everhartii (Ellii & Gall.) Murrill; Pyropoly- porus fulvus (Scop.) Murrill; and Elfvingia megaloma (Lev.) Murrill. Pyropolyporus igniarius: The sporophores of this fungus are among the commonest and best known of the largest fungi. The hoof-like shelves of this fungus occur widely distributed throughout the United States on the apple, oak, alder, beech, birch, maple and other species of broad leaved trees. In Plant IOWA ACADEMY OP SCIENCE 25 Diseases of 1907 by Orton and Ames, it is reported from eight different states from Maine to Montana. The fruit bodies are somewhat hoof-shaped, very hard, the upper surface black, while the fruiting surface is cinnamon brown. They are 4 — 8 inches long, 2 — 4 inches broad, — 5 inches thick, and alv/ays occur singly. The hymenium is made up of rounded pores. The upper surface is marked by concentric furrows and ridges which mark off the annual layers. Thus the fungus is perennial. The location of the sporophore on its host leads us to the question of the conditions favoring the entrance of the fungus. Since the mycelium cannot enter through the living cambium layer of the tree, some means of infection must be provided. These infection areas are provided in a variety of ways. From, the location of the sporophore on the poplar at the knot-holes, we con- clude th«,t it gains entrance through the dying away of the lower limbs, and nature failing to heal the wound formed. The sporophores found upon butter- nut, iron-wood, and the apple were each located at a wound. Hence we con- clude that the fungus must be a wound parasite. The microscopic spores found lodgement in the wounded area, and when proper moisture was obtained it germinated, sending its hyphae into the heart wood. After it had received the proper nourishment, a sporophore was formed, and spores produced. The number of sporophores on a host varies from one to twenty-five. Cross sections of a poplar tree present a very characteristic marking of the wood due to the different stages of decay and the coloration of the wood. The more advanced stages of decay lie at the center, the less advanced at the outer edge. It changes the heart wood to a light yellow color, and a very dark line separates it from the outer area which is a dark brown color from the knot- holes to the center there is the same condition, showing its entrance. Atkin- son (3) stated, “that the peculiar discoloration of the wood accompanied the mycelium of this specie of fungus, and might be sufficient to identify the species even where no fruit forms of the fungus were present.” Pyropolyporus igniarius was found in greatest abundance infecting the pop- lar (Populus grandidentata), in fact, only one specimen was found on each of the apple and iron-wood, while several were found on the butter-nut. The fungus appeared to effect the black poplar more than it did the white; and it appeared to attack no trees less than five inches in diameter. In some groves of poplar the greater per cent of them were infected, while in others it was not so prominent. The effects are easily to be seen in some localities where a greater number of the trees lie on the ground. From this we might conclude that it effects the tree as a whole, causing its decay and finally its fall. To estimate the pos- sible loss is a difficult task; but as these trees are somewhat limited in quan- tity in localities we can readily see that the damage is great. If the tree is not used before it falls, the wood is of but little value, and, as far as lumber purposes is concerned it is of no value whatever. This fungus is' not so serious as a hard wood disease, for it effects only our less important forest trees. Poropolyporus Everhartii: This fungus is found to infest the broad leaved woods of this region, the hardiest and best of our timber, the red and white oak. We find this fungus is not as widely distributed over the United States as the former, and is only known on the oak and occasionally on the beech. In Plant Diseases of 1907 it is not reported. 26 IOWA ACADEMY OF SCIENCE The sporophores are hoof-shaped, very hard, the upper surface a very dark brown, while the fruiting surface is a cinnamon brown. They are — 12 inches long, 2 — 6 inches broad, by 1 — 6 inches thick and always occur singly. The hymenium is composed of rounded pores. The upper surface is marked by concentric ridges, which correspond to the annual growth. Thus the fungus is perennial, and attains to such an age that the upper surface may be covered with tiny moss plants, also deeply checked. If a sporophore is cut open, each year’s growth is definitely marked by a lighter band separating them. This is quite distinct to about half its age, when the remainder is made up of lighter mycelial threads. The condition favoring the entrance of the spores are through wounds, knot- holes, and cavities made by boring insects. It is from the location of the sporo- phore on the host, that we are led to determine the means of infection. There is also a greater diversity in the size of hosts of this fungus. It has been found frequently on red oaks of but three inches diameter; and not in connec- tion with a wound or knot, and in most cases the host has been dead. But in the case of the larger trees it has never failed to be located at some wound or knot. In making a cross section of a tree containing one of these sporophores, I found a cavity which had been formed by some boring insect. The fungus being located at this cavity leads us to conclude that it either entered or grew out through this opening. In the light of the paper by Hopkins (8) on the relation of fungi and insect burrows, we must conclude that this species is a wound parasite. Due to these exposed areas the spore gained access through the cambium layer, and germinated, penetrating the heart wood of the tree. After the mycelium had penetrated the host gathering nourishment, a sporo- phore was formed, which is the only outward sign of disease. The location of these punks on the host varies. It is found on small trees near the ground, while on the larger trees it is observed higher up near a broken limb or wound. It is very seldom there is more than one specimen found on a tree. A study of a cross section of an oak near one of these sporophores shows that the fungus has destroyed a definite portion of the entire heart wood, changing it to a light brown, pulpish mass. The light and dark wood is not separated by a darker area as in the former, but they are inter-mixed. One noticeable effect is that the medullary rays stand out very firm while the sur- rounding area is broken up. The greater abundance of this fungus was found on the red oak, but it is not as common as the former studied. Still I have noticed that it is found but very little among the healthy timber, while among the dwarfed, scrubby jack oaks and the stunted burr-oaks of wind swept hillsides, it is more numerous. From this might we not conclude that the vitality of the tree gave a means of infection. The proportion of trees diseased to those not is very small, in fact much less than in Pyropolyporus igniarius. The effect, economically, of this fungus is rather difficult to judge, as the extent of the disease is not very great. Although we find it scattered in different localities, yet there is no extensive tracts affected. But as its host is one of our most desirable kinds of woods, the result will be more noticeable later, if its spread is not checked. For each year a sporophore discharges myriads of spores, and some of these are sure of finding access in some tree, consequently the infected areas are increased each year. As no study has been made of a large diseased tree, we only form a conjecture as to its probable condition; Plate I. — Fig. 1. Section of living red oak tree (Quercus rubra) near a sporophore of Pyropolyporus Everhartii, showing the decay ; also the cavity formed by a boring insect. ■ Fig. 2. Section of the same tree, six feet above the sporophore, showing the pres- ence of the mycelium also the cavity. Fig-. 2. Fruiting body of Pyropolyporus Everliartii showing the hymenial surface. IOWA 'ACADEMY OP SCIENCE 27 but from our knowledge of the effect on small trees, we may conclude that the lumber quality is destroyed, hence an economic loss, as it is being used very extensively for building purposes. For this reason this fungus is one of the most important economically of any of the species under consideration. Pyropolyporus fulvus: This fungus affects only the diseased trunks of various species of Prunus and is widely distributed over North America and Europe. In Plant Diseases in 1907 it is not mentioned. The fruiting bodies of this polypore vary in size from 1 — 6 inches long, ^2 — ^2 inches broad, by 14 — 11^ inches thick. They form large masses when a large number are joined, as in some instances several limbs or main branches are covered with sporophores. The fruit bodies are elongated usually resupi- nate, very hard, edges nearly black, while the fruiting surface is a dark brown. This fungus does not grow in shelf form, but horizontal to the tree, leaving the concentric ridges only visible at the very edge of the sporophore; and frequently as resupinate forms coalescing in a series. The hymenium consists of regular pores of rounded minute openings. It is a perennial growth, hence tiny moss plants may be found growing upon it. The condition favoring spore entrance is a wounded area. It has been ob- served that the sporophores are more common on the branches than on the trunk, and it has the appearance of working from the top downwards. Upon removing one of these sporophores no wounded' area is visible, yet there are some located near a broken limb. Hence we conclude that it was through this broken limb that entrance was gained. A cross section of a diseased branch shows that it is thoroughly infected, rendering it very brittle, while normally it is tough. Again the alternate area of light and dark wood prevails too near the sap wood. Prom these noticeable features . it appears to attack only definite tissues or else follow the annual growth. Its favorite host is the wild plum, and a few specimens have been observed on cultivated trees when pruned. One wild grove in particular where speci- mens were gathered, there was not a tree unaffected and most of them were dead. It appeared also that the cluster in the timber is much more subject to attack than those in the open, which might be explained by the former being more conducive to infection due to more moisture. Also the question arises if the fungus is strictly parasitic, for I believe specimens were gathered on dead hosts. If it be true mat a plum supports this fungus long after its destruc- tion, it is more tenacious of life than Pyropolyporus igniarius as the sporophore ceases to grow at the death of the host. Among the plums there is a greater proportion of diseased trees than any other yet studied. The economic importance of this parasitic disease lies not in the fact of the commercial value of the wild plum, but in the tendency to infect the tame ones. Then it would have an economic importance for the fruit growers. Elfvingia megaloma: The last fungus for consideration is Elfvingia mega- loma, which is widely distributed over the United States and Canada. It is reported from Nebraska by Dr. Heald as parasitic upon cotton wood; like- wise by D’Allemend from the same state under the name of Fomes appTanatus parasitic upon cottonwood. As a parasite it attacks the red oaks in this region, but has not been found on the cottonwood; as a saprophyte it is found on dead trees, stumps and logs. 28 IOWA ACADEMY OP SCIENCE This fungus is of the bracket form with sporophores varying in size from 2 — 14 inches long, 1 — 8 inches wide, by % — 2 inches thick; it is somewhat hoof- shaped or elongated, very hard, the upper surface dark colored and encrusted, while the fruiting surface is nearly white. The under surface is marked along the edge by an encrusted ridge, and the upper surface is marked by concentric ridges showing that it is perennial. In the popular mind it is associated with etching, because its hymenium changes to a darker color when bruised. As a parasitic fungus on the red oak its sporophore is found near the ground. The means of infection is not very easily determined, as no wounds have been observed; but as the sporophores are located so near the ground we may conclude that infection is brought about through the roots, or at the base of the trunk near the ground line. This seems quite probable as sufficient moisture is one of the requisites for germination. The fact that it does not attack young trees, but becomes parasitic upon older trees in which the vitality has been lowered leads us to conclude that lack of vitality may be a means of infection. The mycelium spreads upward through the entire wood, and the trunk becomes thoroughly infested before the fungus attains sufficient vigor to produce its external fruiting bodies. The wood is rendered very brittle, and the tree is poorly fitted to withstand the force of wind in severe storms. The trees affected have always been large, probably more than thirty years old. The only evidence of the disease is the presence of a sporophore. As a parasitic fungus this one is the least numerous of any yet studied. Only two specimens have been found on living trees. But as a saprophyte it is very common, being found on any dead tree, log or stump. But I believe that the log or stump of maple was more infected by it than any other. Dr. Heald (7) says, “Any logs or woods affected with this fungus should be burned as the fungus continues its growth. It seems quite probable that the vegetative mycelium is often the means of infection, rather than the spore direct.” BIBLIOGRAPHY. 1. Atkinson, G. P. Some wood destroying Fungi. Rep. Louisiana Geol. Surv., 1899: 332- 338. pi. 56-62. F. 1900. 2. Atkinson, G. F. Studies of some shade tree and timber destroying Fungi. Bull. Cornell Agr. Exp. Sta. 193: 199-235. F. 56-94. Te. 1901. 3. Atkinson, G. F, Studies of some tree destroying Fungi. Trans, Mass. Hort. Soc. 109-130. 1902. 4. D’Allemand, B. R. A. The disease of the cottonwood and the lombardy poplar. Ann. Rep. Nebr. Hort. Soc. 190^: 189-193. 1904. 5. Galloway, B. T., & Woods, A. F. Disease of shade and ornamental trees. Year- book U. S. Dept. Agric. 1896: 237-254. F. 53-57. 1897. 6. Hard, M. E. Mushrooms, edible and otherwise, p. xi & 609, F. SOlf.. 1908. 7. Heald, F. D. A disease of the cottonwood due to Elfvingia megaloma. Ann. Rep., Nebraska Agric. Exp. Sta. 19: 92-100. pi. l-J/. 1906. 8. Hopkins, A. D. Insect in.1uries to hard wood forest trees. Yearbook U. S. Dept. Agric. 1903: 313-328. pi. 39 t£ F. 27-J,3. 1904. 9. Marshall, N. L. The mushroom book, xxviii & 170. illust. 1905. 10. Metcalf, H. Disease of ornamental trees. Yearbook. U. S. Dept. Agric. 1907: 483- 494. pi. 58-60 d Fig. 52. 1908. 11. Murrill, W. A. Polyporacea. N. Am. Flora 9: 1-131. 1907-08. 12. Orton, W. A. & Ames, A, Plant diseases in 1907. Yearbook U, S, Dept. Agric. 1907: 577-589. 1908. 13. Schrenk, H. von. Two diseases of red cedar, caused by Polyporus juniperinus n. sp. and Polyporus carneus Nees. Bull. U. S. Dept. Agric. Veg, Path. 21: 1-22. pi. 1-7 & Fig. 1-3.. 1900. Plate III. — Fig. 1. Section of living plum tree (Prunus) showing the decay caused by Pyropolyporus fulvus and also the resupinate form of the fungus. Fig. 2, 11^ Shelving foi'ms of Pyropolyporus fulvus as found on a limb. IOWA ACADEMY OP SCIENCE 29 14. Shrenk, H. von. Some disease of New England conifers. Bull. U. S. Dept. Agric. Veg. Path. 25: 1-56. pi 1-15 d F. 1-3. 1900. 15. Schrenk, H. von. Fungous disease of forest trees. Yearbook U. S, Dept. Agric. 1900: 199-210. pi. 21-25. 1901. 16. Schrenk, H. von. A disease of the black locust (Robinia pseudacacia. L. ) Ann. Rep. Missouri Bot. Gard. 12 : 21-31. pi. 1-3. 1902. 17. Schrenk, H. von. A disease of the white ash caused by Polyporus fraxinophilus. Bull. U. S. Dept. Agric. Plant Indust. 32: 1-20. pi. 15 d fig.. 1903. 18. Schrenk, H. von. The' “bluing” and the “red rot” of the western yellow pine, with special reference to the Black Hill Forest Reserve. Bull U. S. Dept. Agric. Plant Indust. 37: 1-40. pL l-ll 1903. 19. Schrenk H. von. Sap rot and other diseases of the red gum. Bull. U. S. Dept. Agric. Plant Indust. lU: 1-34. pi, 1-8. 5D 1907. 20. S'iecke, E. O. The disease of the oak. Ann. Rep. Nebraska Hort. Soc. 1901^- 233-236. 1905. 21. Spaulding, P. Two fungi growing in holes made by wood boring insects. Ann. Rep. Missorui Bot, Gard. 15. 73-77. pi. 25-:27. 1904. 22. Spaulding, P. A disease of black oaks caused by polyporus obtusus Berk. Ann. Rep. Missouri Bot. Gard. 16: 109-116. pi. 13-19 d fig. 1905. 23. Spaulding, P. Heart rot of Sassafras sassafras caused by Pomes ribis. Science ii. 26: 479-480. 11 O 1907. 24. Williams, P. Disease of the apple. Ann. Rep. Nebraska Hort. Soc. lOO’,: 178-186. 1904. THE UNDERGROUND ORGANS OF A PEW WEEDS. BY L. H, PAMMEL AND ESTELLE D. EOGEL. A study of some of the troublesome perennial weeds and their methods of extermination has led the authors to look up the botanical descriptions of the underground portions and manner of propagation. Some writers have called all underground organs by which the plants in question propagate, rootstocks; others have cautiously said nothing about them and a few have called them roots and rootstock. It was this disagree- ment of authorities, in part, that made it seem desirable to make a more definite study to ascertain exactly how much of the underground portions are roots and how much are stems. This can be done only by a study of cross sections. Very little, so far as we know, has been published in English on the minute anatomy of the plants under discussion. The plants in which we have been especially interested are Quack Grass, Canada Thistle, Horse Nettle, Wild Morning Glory, Bindweed, and Milkweed. The present paper gives the result of our study after making stained mounts of all underground portions. Illustrations of the sections were made with the camera lucida and the photomicrograph. Some Morphological Views. The text-books on General Morphology consulted were Gray\ Robinson and Fernald^ Britton^ and Van Tieghem^ The special papers and bulletins were Hitchcock and Clothier^ Crozier®, Dewey^ Goff and Mayne®, and Hitchcock®. Hitchcock and Clothier state that the European iviornihg Glory (Convolvulus arvensis) propagates by horizontal roots. The same authors also state that the Wild Morning Glory (C. sepium) propagates by slender underground stems. The section of Convolvulus in which C. sepium occurs, Calystegia, is char- acterized by Dr. Gray^® as having creeping filiform rootstocks. The Milkweed, according to Hitchcock and Clothier, propagates by a creeping root on which adventitious buds appear, although Dewey states that the Milkweed and Euro- pean Morning Glory propagate by rootstocks. Dewey“ also states that the ^Structural Botany, also Manual of Bot. ofv Northern U. S. (Ed. 1) 1848. XIV. 244. -Gray’s New Manual of Bot. (Ed. 7). 882, 858. 1908. ^’Manual of the Flora of the Northern States and Canada. ^Traite de Botanique. 686. .sBull. Kan. Agr. Exp. Sta. 76: 1-23. «Rep. U. S. Dept. Agr. 1886: 85. ^Far. Bull. U. S. Dept. Agr. 28:14. ^First Principles of Agriculture. 107. “The Subterranea.n Organs of Compositse. Trans. Acad. Sci. St. Louis. 9: 1, Ipl. i“Syn. FI. of N. A. 2:215. iil.c.:14. (31) 32 IOWA ACADEMY OP SCIENCE Horse Nettle is abundantly propagated by slender perennial rootstocks, while others state that it propagates by roots. With reference to the Canada Thistle, Vasey and CrozieP% Goff and Mayne^'^ and Dr. Gray state that the plant has creeping rootstocks which spread in every direction. Besides one of the present authors^®, many other writers have accepted and made similar statements without giving the subject much attention. Anatomical Structure. Since the general characters will not always enable one to determine the nature of the underground organ, a microscopical study was made. In this way, we were able to determine definitely the extent of the root and stem. The microscopic structure of roots and their origin is sufficiently indicated in many special treatises on this subject, especially by such writers as De Bary^®, Vesque^^ Marie^®, Jeffrey^®, Costantin^® Gerard^\ WorsdelP^ SargenP®, Van Tieghem-^ Strasburger, Noll, Schenck, and Karsten^®, Solreder^ Holm-\ Andersson^®, DodeP®, Goldsmith®®, and Van Tieghem®^. Girsium arvense (L.) Scop. Canada Thistle. Root. The root is usually horizontal or occupies a vertical or oblique posi- tion in the soil, frequently strongly contorted; whitish or light brown with a strong odor; the small roots occur on the stem without definite order; when immersed in water a blackish extractive matter is removed. The thicker roots produce numerous adventitious buds along their course. The depth in the soil iq.c. :85. i3Lc. :109. i^Syn. FI. of N. A. i:393. ^^Pammel. Bull. la. Agr. Exp. S'ta. 70 :324. i®Comparative Anatomy of the Vegetative Organs, of the Phanerogams and Ferns. English Translation by Bower and Scott. Oxford. 1886. i^De’l Anatomie des tissus appliquee a la Classification des plants. Nouv. Arch, la Mus. d’ Hist. Nat. II. 5:291. i®Recherches sur la structure des Renonculacees. Ann. d. Sci. Nat. Bot. VI. 20: 1-180. 8 pi. ^®Coulter and Chamberlain, Morphology of Angiosperms. 311. The Morphology of the Central Cylinder in the Angiosperms. Trans. Can. Inst. 40. pi. 7-11. -®Costantin. Etude comparee des tiges aeriennes et souterraines des Dicotyledones. Ann. Sci. Nat. Bot. VI. 16:1-176. pi. 1-8. 2iRecherches sur le passage de la Racine a la Tige. Ann. Sci. Nat. Bot. VI. 11:279- 430. pi. 1-18. 22A study of the Vascular System in certain orders of the Ranales. Ann. Bot. 22 : 651-628. pi. S2, S3, 5of. 2®A Theory of the Origin of Monocotyledons founded on the Structure of their Seed- lings. Ann. of Bot. 77:1. 7 pZ. 10 f. -^Recherches sur la symetrie de structure des plantes vasculaires. Ann. Sci. Nat. V. 78:185. 2®A text-book of Botany. Eng. Trans., Lang. 128, 142, 154. 1908. 2®Syst. Anat. d. Dicotyledonen, 1899. 27Am. Jour. Sci. y/:298. (1897); 9:355. (1908). 9:355. (1900) 7:5. 1899. 28Ueber die Entwickelung der primaren Gefassbundelstrange der Monokotyledonen. Bot. Centrbl. 87:586. 29Der Uebergang des Dicotyledonen Stangels in die Pfahl Wurzel-Pringsheim Jahrb. 8:149-193. pi 11-18. soBeitrage zur Entwickelungsgeschichte in Stengel und in der Hauptwuzel der Dico- tyledonen— Dissertation. 1876. siTraite de Botanique. 686, 750. IOWA ACADEMY OP SCIENCE 33 at which these huds occur varies from a few inches to more than two feet from the surface of the ground. It is not unusual for others among our common thistles to produce adventitious huds. This is indicated hy Hitchcock and Clothier^- for Cirsium undulatum. It is also true for Girsium canescens^^ which spreads much like Canada Thistle. Dr. Bessey writes us that he observed this many years ago for this species. The secondary structure is comparatively simple. The epidermis is per- sistent. The cortial parenchyma consists of twenty or more layers of thin- walled, somewhat irregular cells, and small intercellul'ar spaces. These paren- chyma cells are filled with small starch grains. The cells of the endodermis do not differ materially from the cells of the cortex. Projecting into the vas- cular region and lying between the phloem and xylem plates, are other broad, primary, medullary rays much wider in the region of the sheath, gradually tapering to a point, toward the center. The phloem elements occur in arched area between the medullary rays. The cambial elements lie between the xylem and arched phloem. The elements of the xylem consist of scalariform ducts and parenchyma cells which are thin walled. Stem. In numerous specimens examined by us the shoots coming from the roots had small scales and buds along the sides; these for the most part do not develop but can do so when the strong terminal bud is cut off or injured. The microscopic structure consists of an epidermis of a single layer of cells, slightly longer than wide with the outer wall thicker than the lateral walls and carrying a brownish pigment. This is followed by the cortex consisting of many layers of thin walled irregular cells, in which starch and other reserve food products occur. The intercellular spaces are small. The fibrovascular bundles are arranged in a circle and are of the collateral type. The scleren- chyma elements are arranged across the outer and inner portions of the bundle. The phloem is situated between the sclerenchyma and the intrafascicular cam- bium. The tracheary elements vary with the size of the bundle. These ele- ments consist of spiral, scalariform, and ringed ducts. 'Conclusion. The most important method of propagation in the Canada Thistle is by means of the large roots by which the plant spreads through the ground. Such stems as do .not occur in the ground come from the adventitious buds on the roots. The seminal roots descend into the soil and later form these adventitious buds. Under some conditions, especially when the plant is injured or when a new shoot is produced in the spring, adventitious buds may be found on the stem. Solanum carolinense L. Horse Nettle. The roots and stems of some species of the Solanacese have been studied by Gerard^^, also by Costantin®^. Stem. The twisted woody stem with its numerous lateral roots resembles the root in a very striking manner; in fact it is difficult to distinguish root from underground stem except by microscopical examination. During the winter it dies back near to its origin in the root. The thick walled epidermis 32L.c:13. ^^Con. Bot. Dept. la. St. Coll. Agr. and Mech. Arts. 16. 3^1.c. 375, pi. 18 f. 53-61 st^l.c. 132. 3 34 IOWA ACADEMY OF SCIENCE surrounds the cortical parenchyma, also thick walled in which are stored large, eccentric starch grains which resemble those found in the potato tuber. The fibroyascular bundles are of the open collateral type, with sieve elements next to the cortex, the xylem next to the pith and separated from the phloem, by the cambium. The medullary rays extend from the cortex to the pith and contain a few starch grains. The parenchyma cells of xylem are thick walled. Root. The tortuous roots vary a great deal. In younger specimens they are somewhat slender, becoming thick and hard with ages, lightly brown in color with strong odor. They extend vertically into the soil from one to four feet or even five feet. Numerous adventitious buds are produced along the course. A microscopical study shows that the organs which produce the buds are roots; these are the usual radial bundles, but the medullary rays secondary and primary are small and lie between the xylem elements. In the secondary structure a few layers of cork cells are developed and underneath a large num- ber of parenchyma cells with walls somewhat thicker than those of the cork cells. These are abundantly filled with large starch grains and a considerable quantity of protein matter. The bulk of the root consists of the cortex. The xylem is separated from the cortex by a well defined area consisting of the endodermis a few layers of very thin walled cells. The medullary rays are harrow and extend into the xylem area between the bundles. These cells also contain starch grains. The xylem elements consist of scalariform and pitted ducts. Asclepias syriaca L. Milkweed. Roots. The roots of Milkweed have been traced in the soil for fourteen feet. They are generally horizontal though occasionally vertical. A single root removed from the soil and placed in a moist place at once produced adven- titious buds along its surface. At very short intervals several dozen of these buds' could be made out with the naked eye; many more could be made out when sectioned. The roots are whitish and much thickened. Microscopically the roots show that the bundles are of the radial type. The structure in an older root shows thin walled epidermal cells nearly isodiametric although in some cases longer than wide. Underneath the epidermis there are two or three layers of thin hypodermal cells. The cortex is differentiated into two parts, the outer por- tion of large irregular thin walled cells and small intercellular spaces and the inner cortical region of cells which become smaller toward the endodermis. The cells of the cortex contain a large number of small starch grains and compound calcium oxalate crystals. In secondary growth the xylem consists of bundles of scalariform ducts varying in number from one to five, which are scattered throughout the parenchymatous tissue of the vascular region. Starch grains and calcium oxalate crystals are also found in this parenchymatous tissue. Stem. The difference in the origin of lateral roots and that of adventi- tious buds on the root was studied somewhat at detail in the Milkweed. Lateral roots originate endogenously within the vascular bundles and with a well defined protoxylem push through the cortex. On the other hand stems originate possibly from a single cortical cell just underneath the epidermis. This cell becomes actively meristematic and soon involves other cells which differentiate definitely into plerome and periblem. The epidermis lying just IOWA ACADEMY OF SCIENCE 35 above organizes the dermatogen. Just back of the meristem appears the pro- toxylem which for some time is entirely separated from the vascular tissue of the root; the tissues of the cortex remain undisturbed for some time. How- ever, the oldest buds which we have sectioned show signs of the vascular region of the stem extending down to the one in the root. Convolvulus sepium L. Common Morning Glory. Roots. The small whitish roots usually spring in pairs from the base of the scales. The roots like the rhizomes are extremely fragile. The number and character of the secondary roots differ in different plants. Stem. The plant propagates freely by its underground stem. The rhizomes are fleshy, dirty white in color, and very fragile. They extend horizontal, verti- cal, oblique, ascending, or descending from a few inches to two or three feet into the ground. The nodes occur at short intervals. The small roots usually occur in pairs, a point noted by Hitchcock and Clothier. One or more aerial stems spring from the upper nodes. The anatomy of the stem has been studied by Gerard^® and Costantin®^ the latter giving a careful description of the anatomical structure. The root stock is essentially a storage reservoir for food, every part but the vascular tissues being fllled with starch, a comparatively small part being occupied by the vas- cular elements. The epidermis consists of somewhat elongated thin walled epidermal cells, underneath which are small hypodermal cells, and small inter- cellular spaces. The cells vary somewhat in size. The inner layer of the parenchyma cells forms the endodermis. The vascular elements form a ring connected by the cambium. There are four large bundles with a few inter- vening very small bundles. The bundles belong to the bicollateral type with sieve elements and cambial layers between the endodermis and pith paren- chyma. The sieve elements towards the pith form irregular areas. The xylem elements consist of scalariform ducts. The pith parenchyma is sharply differ- entiated from the cambium. Convolvulus arvensis L. Bindweed. Roots. Convolvulus arvensis propagates by means of small creeping horizon- tal roots. The younger ones are whitish, becoming much darker in color with age. Small branches appear at irregular intervals. The anatomical structure consists of the following parts, an epidermial layer of rather large cells, a deeply staining hypodermal layer, followed by two layers of cells somewhat longer than wide. The remaining eells of the cortex are large, gradually becoming smaller toward the vascular region. The cells contain a small amount of protein, iSie starch grains having disappeared at the time of examination in the spring. Some of the cells contain crystals of cal- cium oxalate. A conspicuous nucleus and nucleolus is present in most of the cells. The xylem consists of large ducts and thick walled cells, arranged radially with the phloem. The medullary rays extend from the cambium in toward the center of the root which consists of five rays projecting into the xylem. The root produces adventitious buds. These give rise to short vertical stems which often give rise to other new stems. 361. C. c.. 36 IOWA ACADEMY OF SCIENCE Agrovyron repens L. Quack Grass. The vegetative reproductive organs are commonly called roots by the laity, but are universally regarded as rhizomes by botanists. A study of the general morphology and histology leaves no doubt as to their stem characters. Roots. The whitish fragile roots of the rootstock vary in number and they spring from below the scale. Rhizome. The rhizomes are generally horizontal except where the stems grow toward the surface of the soil, occuring from one inch to 4-5 inches below the surface of the soil. The greater majority, however, are found not more than three inches from the surface. The creeping rhizomes are from 1 — 3 feet long nearly terete, divided into nodes which are from an inch to two inches apart; at the nodes numerous small roots and buds spring from beneath the scales. The histological structure of the rhizome is as follows: The epidermal layer consists of thick walled small epidermal cells. Underneath it is the hypoderm, of two or three layers of cells, also thick walled. Between the vascular ring and hypodermal layer are the large cortical parenchyma cells and the endodermis very much thickened toward the vascular bundles. A short account of the histology of the rhizome is given by Fluckiger^®. Sayre^^^’ figured the stem, giving no description, while Greenish^® gives a short description, and a small, unsatisfactory figure. The fibrovascular bundle is of the closed col- lateral type, consisting of two or three, sometimes four, large tracheae and the small phloem patch between and a little above the tracheae. To Dr. Trelease of the Missouri Botanical Garden, to Dr. Beal of Lansing, Mich., and to Mr. R. I. Cratty of Armstrong, Iowa, we are indebted for aid in securing some of the material used in this paper, and to Miss King for some drawings. •■**^Pharmacog:raphia. A History of the Principal Drugs of Vegetable Origin met with in Great Britain and British India. 729. 39A Manual of Organic Materia Medica and Pharmacognosy. (Ed. 2.) 440. f. 298. ^oAn Introduction to the Study of Materia Medica. 310. f. 151. IOWA ACADEMY OP SCIENCE 37 DESCRIPTION OP PLATES. PLATE I. Fig. I. Rhizome of Lycoims ruhellus, showing scales and roots. Fig. II and III. Root and rhizomes of Canada Thistle {Cirsium arvense). Fig. II, st underground stem, r root, b buds from stems and roots, the stem from an adventitious bud at r; lateral roots along the stem. Fig. III. sc scales on stem, r root, b young stem from root. Pig. IV. European Bindweed or Morning Glory {Convolvulus arvensis). r root, b adventitious bud, st underground stem. Fig. V. Bindweed or Morning Glory {Con- volvulus sepium). Underground stem with scales at sc^ and buds at the nodes, also a pair of roots below the scales at r. Fig. VI. Wooly Thistle {Cirsium canescens) r thickened root with stems s and y from adventitious buds. All figures drawn by Charlotte M. King. PLATE II. Upper figure, cross section of the root of Canada Thistle {Cirsium arvense) showing the broad cortical parenchyma between the epidermis and the endodermis ; inner poi’tion showing radial bundles, the medullary rays extending into the vascular region. Lower figure, cross section of the rhizome of Canada Thistle {Cirsium arvense) showing ar- rangement of bundles. Micro-photograph by Colburn. PLATE III. Upper figure. Cross section of root of Milkweed {Asclepia^ syriaca). The vascular cylinder and the cortical parenchyma from which an adventitious bud has sprung. Lower figure. Cross section of the root of Horse Nettle {Solanum carolinense) . Radial bundles in center ; large cortical parenchyma cells densely filled with starch grains. Microphotographs by Colbuim. PLATE IV. Pig. I, Cross-section of old root of Common Milkweed {Asclepsias syriaca). ep epi- dermis, cor cortical parenchyma containing crystal receptacles of calcium oxalate cr, c cambium, xy duct, jjp parenchyma among the xylem elements. Fig. II, the woody root of Horse Nettle {Solanum carolinense). x ducts, pw woody parenchyma, p parenchyma. Fig. HI. General view of bundle root of Horse Nettle showing the ducts at X and the surrounding parenchyma, less magnified than in Fig. H. Pig. IV. Cross section of outer portion of stem of Convolvulus sepium. e epidermis, p paren- chyma cells with starch, a simple and compound starch grains, higher magnification than at p. Fig. V. Portion of root of Canada Thistle {Cirsium arvense). Cor cortex, par parenchyma cells of the cortex, m medullary rays, x ducts, p parenchyma, c cambium. PLATE V. Pig. I. Cross section of root of Bindweed {Convolvulus arvensis). e epidermis, h hypodermal layer, c cortex, n nucleus, granular cytoplasm evident, c’ cells of lower portion of cortical parenchyma, cam cambium, p parenchyma cells surrounding the ducts at X. Pig. 11. Cross-section of inner portion of root of Bindweed {Convolvulus arvensis), showing bundle region, parenchyma cells and five rays. Drawn by Charlotte M. King. Fig. HI. Portion of root of Canada Thistle, showing two large ducts and surrounding parenchj^ma cells. Pig. IV. Cross-section through rhizome of Quack Grass, e epidermis with thick walls underneath, sc sclerenchyma, par underlying thin walled parenchyma, end endodermis, xy ducts with thick walled sclerenchyma between pJi phloem. Pig. V and VI. Root of Horse Nettle {Solanum carolinense). Fig. V. Cork, cork cells and underneath parenchyma cells and starch grains. Fig. VI. Cortical parenchyma cells with starch grains. 38 IOWA ACADEMY OF SCIENCE Roots and rhizomes of I Lycopus ruhellus, II and III Cirsium arvense, IV Convolvulus arvensiSj V C. sepium, VI Cirsium canescons. ♦ Plate II. Upper figure, stem, lower, root of cirsium arvense. Plate III. Upper figure, root of asclepsias syriaca: lower figure, root of solanum carolinense . Plate IV — I root of Asclepias syriaca, II and III root of Solanum caroUnense. IV stem of convolvutus septum. V root of cirsium arvense. 40 IOWA ACADEMY OF SCIENCE I>late Y—1 and II Root of Convolvulus arvensis. Ill Root of Cirsium arvense. IV Quack grass stem. V and VI Root of Solctnuni carolinense. NOTES' ON FACTORS IN FUNGUS DISEASES OP PLANTS, WITH RECORDS OP OCCURRENCES OP PLANT DISEASES AT AMES FOR A PERIOD OP TWENTY-FIVE YEARS. BY L. H. PAMMEL AND CHAELOTTE M. KING. STATEMENT OF THE PROBLEM. Literature. Nature of Disease. Two Kinds of Disease. Factors of Environment in Plant Disease. The Plant an Organism Responsive to Outside Conditions. Influence of Soil and Air in Plant Disease. * Influence of Soil and Moisture. Influence of Lig-lit. Influence of Acclimatization. Fungi as the Cause of Disease. Two Kinds of Parasitic Fungi. How Fungi are Spread. Wind an Agent of Infection. Water an Agent of Infection. Carrying of Fungi by- insects. Other Animals as Means of In- fection. Fungi Scattered by Explosive Properties. Fungi Scattered by Farm Tools. Soil Moisture and Fungus Diseases. Asparagus Rust. Celery-root Rot. Grain Rust. Weather and Fungus Diseases. Exoasceae, Rust. Peronosporeae. Monilia Disease. Apple Scab. Some Epidemics of Fungus Diseases. Mildews. Rusts. Downy Mildews. Apple Blight. Clasterosporium, Immunity and Disease — resistant varie- ties, Acclimatization. Some resistant varieties. Immunity from one disease on ac- count of the presence of an- other. Susceptibility of transplanted plants. Immunity through fertilizers. Immunity by presence of toxin. Biologic Species. It is important in a study of plant diseases to understand the causes of wide-spread epidemics; notes on the prevalence of diseases, and their seasonal and geographical distribution, are an aid to this knowledge. LITEEATUEE ON THE SUBJECT OE PLANT DISEASES. Some Iowa Puhlications. In 1882 was begun by L. H. Pammel a series of notes on fungi common in Iowa, especially in the vicinity of Ames. These notes have been presented in various publications as follows: The Asparagus Rust in Iowa. Bull. la. Agr. Exp. Sta. 53 : 60-67. Bacteriosis of Rutabaga. Bull. la. Agr. Exp. Sta. 27:130-134. Corn Molds and disease. Bull. la. Agr. Exp. Sta. 54 :250. Corn Smut. Proc. la. Acad. Sci. i:95-96. Diseases of ‘plants at Ames, 1894. Proc. la. Acad. Sci. 2:201-208. 1894. Experiments with fungicides. Bull. la. Agr. Exp. Sta. 16 :316-329. Fungus diseases of grasses. Bull. la. Geol. Survey. 1:185-292. Fungus diseases of grasses. Bull. la. Agr. Exp. Sta. 54:250-344. Fungus diseases of plants and their remedies. Rept. la. Hort. Soc. 3 :440-444. The most important factor in the development of rust. Agr. Sci. 8:287^291. New Fungus diseases in Iowa. Jour. Mycology 7:95-103. Notes on some fungi common during the season of 1892 at Ames, Iowa, Agr. Sci. 7:20-27. Potato-rot and its prevention. Bull la. Agr. Exp. Sta. 27:120-130. The potatO-rot fungus. Press Bull. la. Agr. Exp. Sta. July, 1903. (41) 42 IOWA ACADEMY OF SCIENCE Prevention of corn and oats smut. Bull. la. Agr. Exp. Sta. 20: 721-728. The Apple Rust and Cedar Apple fungi in Iowa. Bull. la. Agr. Exp. Sta. 84 :2-55 Some diseases of plants common to Iowa cereals. Bull. la. Agr. Exp. Sta. 18 : 488-505. Some fungus diseases in Iowa forage plants. Proc. la. Acad. Sci. 1:93. Some unusual fungus diseases of Iowa during the summer of 1903. Treatment of fungus diseases 1892. Bull. la. Agr. Exp. Sta. 20:711-712. Treatment of spot diseases of the cherry and currants, and potato blight. Bull la Agr. Exp. 20:716-720. Treatment of some fungus diseases. Bull. la. Agr. Exp. Sta. 17 : 419-443. By Pammel and Carver. Proc. la. Acad. Sci. 2:201-208. Some years ago, Dr. C. E. Bessey^ published occasional notes on the abun- dance of fungi in Iowa. -Dr. Halsted® also published notes on the abundance of certain species of fungi in the vicinity of Ames. Notes dealing with the abundance of American Fungi have been reported by many other investiga- tors^ Dr. Erwin F . Smith, in a paper on the peach curP, calls attention to the climatic conditions favoring the spread of peach curl, and Dr. Halsted® kept a record of the abundance of certain fungi in New Jersey. F. C. Stewart^ has made a series of experiments in the control of potato diseases of New York, giving notes on abundance. GENERAL PUBLICATION NOTES.* For a number of years, Mr. Orton of the United States Department of Agri- culture, Bureau of Plant Industry, has kept a record of the important diseases occurring in different parts of the United States. These records are based upon information received through assistance of Bolley, Carleton, Heald and other botanists in different states. Dr. Salmon® has, for a number of years, called attention in Gardener's Chronicle, to the spread of Powdery Mildew of the gooseberry. In Europe records have been kept by many investigators®. THE NATURE OF DISEASE. Prof. Marshall Ward says^®, “Disease, therefore, may be said to be a varia- tion of functions in directions or to extents, which threaten the life of a plant, the normal in all cases being the state of the plant characteristic of the * Stewart, Eustnce & Sirrine. Potato Spraying Experiments in 1902. Bull. N. T. Gen. Agr. Exp. Sta. 221: 236-261. Stewart, Eustace & Sirrine. Potato Spraying Experiments in 1903. Bull N. Y. Gen. Agr. Exp. Sta. 2^1:251-292. Stewart, Eustace & Sirrine. Potato Spraying Experiments in 1904. Bull. N. Y. Gen. Exp. Sta. 26^:95-204. Stewart, Eustace & Sirrine. Gen. Exp. Sta. 279:1-16. Stewart, Eustace & Sirrine. Gen. Exp. Sta. 299:238-321. Stewart, French & Sirrine. Gen. Exp. Sta. 697:439-463. 2^merican Naturalist. 29:806; 21:666. 3The Ash-leaf Rust. Bull. Dept. Bot. la. St. Coll. Agr. and Mech. Arts. 1886:55. Potato Spraying Experiments in 1905. Bull. N. Y. Potato Spraying Experiments in 1906. Bull. N. Y. Potato Spraying Experiments in 1907. Bull. N. Y. ^Jones and Morse, Potato Diseases and Their Remedies. Ann. Rep. Vt. Agr. Exp. Sta. 1904-1905: 272-291; 1903-1904: 336-402 ; 1902-1903: 155-156.. Uour. Mycology. 6:107-110. ®Notes upon Peronosporeae for 1892. Rep. N. J" Agr. Exp. Sta. 1898: 276; 1997: 440. ■^Potato Diseases of Long Island in the Season of 1895. Bull. N. Y. Agr. Exp. Sta. 101: 70-86. 8A Monograph of the Erysiphaceae. Memoirs of ■ the Torrey Botanical Club. Vol. 9:71. ®P. Magnus. Verzeichniss der von 11 August bis September in Bayern gesammelten meist parasitischen Pilze. Separat. Berichte d. Bayrischen Bot. Gesellsch. zur Erfor- schung der Heimischen Flora. lODisease in Plants: 91, 93. De Bary. Comparative Morphology and Biology of Fungi, Mycetozoa and Bacteria. IOWA ACADEMY OF SCIENCE 43 species. Clearly then the idea of disease implies danger of premature death, and probably this is as near as we shall get to a satisfactory definition.” “If we agree that a living plant in a state of health is not a fixed and un- altering thing, hut is ever varying and undergoing changes as its life works out its labyrinthine course through the vicissitudes of the ever-varying en- vironment, then we cannot escape the conviction that a diseased plant, so long as it lives,' is also varying in response to the environipent. The principal difference between the two cases is, that whereas the normal healthy plant varies more or less regularly and rhythmically about a mean, the diseased one is tending to vary too sudenly or too far in some particular direction from the mean; the healthy plant may, for our present purposes, be roughly likened to a properly balanced top spinning regularly and well, whereas the diseased one is lurching here, or wobbling there, to the great danger of its stability. For we must recognize at the outset that disease is but variation in directions dangerous to the life of the plant. Health consists in variation also, but not in such dangerous grooves. That the passage from health to disease is gradual and ill-defined in many cases will readily be seen.” “Now take the case where the roots are maintaining their maximum func- tional activity, but the leaves — owing to want of light, too much moisture or too low a temperature of the air — are functionally depressed. Here we get a state of oversaturation with water set up, the tissues are turgid to bursting point, what supplies do traverse the sieve-tubes, cortex, etc., do so slowly and are excessively diluted, and the cambium again forms less wood, but the lumina of the vessels are larger and the lignification less complete. Growth in length is excessive, but more leaves are formed, though they are apt to be abnormally thin and may be small. Little or no reserves are stored anywhere, and the watery tissues contain dangerously diffusible substances which may render them an easy prey to parasitic fungi. Here again, however, if the disturbance of equilibrium has not gone too far, and if the season permits, the new leaves may come into full activity and the situation be saved by transpiration and assimilation gradually increasing and restoring the equilibrium. But, as be- fore, the plant has suffered, and shows the effect in its weak shoots, retarded fiowering, and other ways.” “Such plight as is here described may actually be attained in greenhouses where over-watering is the fault, and even in the open it is not uncommon in rainy summers, or in plantations where dominant trees get the upper hand and partially shade more slowly growing species, or in fields where rank grass is allowed to overwhelm crops of lower stature.” Plants like animals are sensitive, and the maintenance of health is dependent on its sensitiveness. The healthy plant therefore manifests this in the greatest degree. Health, therefore, is a condition in which the reaction between the organism and the surroundings are perfect. The condition, as J. Reynolds Green^®^ says in which the relationship to each of these factors (light, temperor ture and moisture) is satisfactory is generally spoken of as one of tone, and the influence which each exerts when it affects the plant uniformly is spoken of as a tonic influence.” lOaAn Introduction to Vegetable Physiology, 358, 44 IOWA ACADEMY OF SCIENCE TWO KINDS OF DISEASES, Diseases of plants may be grouped under the following main heads; (1) so- called physiological diseases, due to the action of the non-living environment, such as the soil, atmosphere, temperature and light, (2) those produced by living plants and animals. FACTORS OF ENVIRONMENT IN PLANT DISEASE. THE PLANT AN ORGANISM RESPONSIVE TO OUTSIDE CONDITIONS. A new era is approaching in vegetable pathology, in which the plant is the center. The lamented H. Marshall Ward^^ has well put it in the following words, “Until comparatively recent times it was the habit of farmers, foresters, planters and gardeners, all the world over, to look upon the plant as a mere item or as a mystery of Importance in their calculations, and to regard the soil as the ‘chief factor in their studies. Now all is changing, and the world is gradually awmkening to the recognition of the truth that the soil and the clouds and the atmosphere are merely reservoirs of more or less inert materials, from which the living plant draws its supplies, and works them up by means of energy focussed from the sun, into new plant substance.” The life processes of all plants are essentially similar. The green plant constructs its material from carbon dioxide and water, but carbon dioxide is not food for higher plants any more than it is for the fungus. The higher plant as well as the fungus feeds on the carbohydrates, made by the green plastids called the chlorophyll grains. The plant then is a living machine making food out of raw material, breaking up the carbohydrates and making the living protoplasm, a highly complex substance, thus utilizing the energy of the sun, and storing the material made for future use. This stored ma- terial is used to build and construct new protoplasm, cells, and to repair waste. The activities of the plant will depend on conditions from without. Every living plant is therefore influenced by certain factors; these may be grouped under soil, heat, light, moisture, air and living organisms. In order therefore to protect plant life from the invasion of fungus diseases, we must have accurate knowledge both of the diseases and the conditions which induce them. Soil and Air. The soil in which the root hairs of the plant occur, consists not merely of dead organic matter but of living organisms as well, which play an important part in the activities of the plant. These organisms not only require organic materials, but oxygen, to carry on their work. Near the sur- face the decomposition of organic matter goes on much faster than in the subsoil, because there is more oxygen present, and the conditions for con- structive work are more favorable. A raw" prairie soil seems to be less favor-* able for decomposition of organic matter than a thoroughly tilled soil. This consideration is intimately connected with the diseases of plants, as will be shown under the heads of rust. Soil and Moisture. Another factor in connection with soils is the relation they bear to the solutions they yield when in contact with water. Some salts are held, others pass. Some soils hold water more than others. This is a factor of utmost importance to the plant in health and disease. Light. Too much moisture may lead to disease, especially when there is not sufficient light, for it may make the tissues so delicate that the plant is ^iDisease in Plants. 1. IOWA ACADEMY OF SCIENCE 45 ready for the entrance of fungi. Especially is this true of the spores of rust fungi which under warm and humid conditions germinate and then readily enter the host plant. Acclimatization. Many plants of arid regions are affected with fungi, though of course never so seriously as in more humid regions. The plant itself for want of acclimatization may become subject to disease, as will he shown later. The whole subject of health and disease is a complicated one and involves a great many factors. For a discussion of some of these problems the works of Marshall Ward^^ Gallo way^^ Bolley^^ Sachs^% PfeffeF®, JosF^, Kuster^®, Tu- beuP, Sorauer^®, De Bary^\ Wolf and ZopF^ should be consulted. FUNGI AS THE CAUSE OF DISEASE. Many years ago the German chemist Liebig^® attached much importance to chemistry in a study of the diseases of plants. He argued that in the case of potato rot the plant is diseased and therefore yields lo the attacks of the potato- rot fungus. . It was long thought by the followers of Liebig that the analyses of dead plants or the soil which contained them would reveal the cause of disease. Later the studies of Boussingault changed the attitude of agriculture towards these problems, and the experiments of Sachs revolutionized the whole subject of plant physiology. De Bary^^ took a view of the matter different from that of Liebig because it had been conclusively shown that apparently healthy plants may be inoculated by a fungus and produce the characteristic disease. By the introduction of pure cultures of fungi and bacteria, a new era of investigation has been introduced which no longer leaves any doubt about the causal relationship of disease and the organism. For a study of parasitic fungus diseases the same rules should apply as in a study of bacterial diseases in animals and plants. THE KINDS OF PARASITIC FUNGI. The parasitic fungi have been grouped with regard to relationship to host under the following heads by Tubeuf: 1. Epiphytes: (a) with haustoria which only sink into the outer mem- branes of the host; (b) with haustoria penetrating into the cavity of the host- cells. 2. Endophytes: (a) with a mycelium which grows in the walls of the host- cell, and is generally nourished without the aid of haustoria; (b) with a i^Disease in Plants. ^^The Health of Plants in Greenhouses. Yearbook U. S. Dept. Agr. 1895:247. ^^Encyl. of Agr. 2:47-53. I'^Dectures on the Physiology of Plants. ^®Physiology of Plants. Pflanzen-Physiologie. i^Lectures in Plant Physiology, ispathologische Pflahzenatoniie. ^^Diseases of Plants. Engl, translation W. G. Smith. 2<’Handbuch der Pflanzenkrankheiten. 2iUntersuchungen uber die Brandpilze und die durch sie verursachten Krankheiten der Pflanzen. 22Krankheinten der landwirthschaftlichen Nutzpflanzen durch Schmarotzerpflanzen. 23Lectures in Agricultural Chemistry. 24De Bary. Comparative Morphology and Biology of Fungi, Mycetozoa and Bacteria. 46 IOWA ACADEMY OF SCIENCE mycelium which grows in the intercellular spaces only, and is nourished with or without haustoria; (c) with a mycelium which penetrates into the host- cells and becomes an intracellular mycelium; (d) lower fungi which live com- pletely in host-cells.” HOW FUNGI AEE SPEEAD. The mycoplasma theory of infection with the seed in view of recent re- searches is untenable. Dr. H. Klehahn^^ in discussion of the mycoplasma theory of Eriksson, cannot agree with Eriksson in regard to this kind of infection. The Puccinia gluma- rum did not appear when the sources of infection were absent. Puccinia sim- plex and R. graminis made their appearance only when the plants were placed in the open air. Seeds coming from plants that had been badly rusted the year before produced very little rust when sown. Infection according to this author is due largely to spores carried by animals and wind. It also appears that plants badly rusted in the fall and permitted to remain in the field produce very little rust in the succeeding summer. Agencies of Infection. The wind, dew, and rains, insects, snails, and other animals, as well as human agencies, are responsible for the spread of fungus diseases. The Wind an Agent. That the wind sometimes plays an important part in the spread of fungus diseases has been repeatedly observed. An interesting case is noted by Dr. Halsted^®. The particular field in ques- tion had been cut off earlier in the season so that a new growth made its appearance, and on September 6th the asparagus brush was about four or five feet high, but the rust was only on one side of each plant. The rusted side was at right angles to lines drawn from an old and very badly rusted patch of asparagus about forty rods away and the source of infection was undoubt- edly the old bed. Dr. Sturgis^^ calls attention to the infection of lima bean mildew" by the wind. Thus he observed the disease abundant on a farm for a distance of about one mile on a straight line from the Station but none were observed at this time, August 14th, on the Station vines. On the following day two mil- dewed pods were brought from the infected farm and the mildew rubbed upon the pod of a single healthy plant at the end of each row. The wind varied from northwest to northeast and within a week the mildew appeared abundantly from the two infected pods and from this plant swept on to the adjacent plants. Water as an Agent. Water sometimes helps to scatter fungi as in case of zoospores of the potato rot fungus which are motile. Moist leaves coming in contact with each other through the wind, must be a factor of some importance in the dissemination of such diseases as the Downy Mildews, where zoospores are formed. These diseases are always more important during warm years when rains are frequent and the atmosphere is humid. Fungi Spread hy Insects. We have seen many leaves of grapes affected by powdery mildews which showed the outlines of the movements of snails over the leaf, the disease appearing^® where the slimy body of the insect came in contact with the leaf. Who has not seen numerous flies feeding on the 25Zeit. Pflanzenk. 1898 : 321. 19 0 0 : 70. 26Torr. Bot. Club. 25:159. Gaz. 25:193. IOWA ACADEMY OF SCIENCE 47 ephacelial stage of ergot? These flies in favorable season like 1907 in Iowa, produce a wide-spread infection. The cabbage butterfly is largely responsible for conveying not only the cabbage rot {Pseudomonas campestris) but a bene- ficial bacterial disease destructive to the larvae of the same insect. Insects are also largely responsible for carrying the rust of the red cedar ( G^mnospomn- gium macropus) to the apple tree. The cedar apple fugus furnished a very attractive food for them. Bees, the hctive pollinators of the apple, also carry the bacteria of apple blight, which is found according to Waite in the nectar of the blossoms of the apple. Aside from this conveyance, flies feeding on the exudate on the stems affected by pear blight also convey the disease. Insects feeding on rust spores convey the same to neighboring plants. Plies and other insects aid in scattering spores of the spot disease of the cherry. These spores cling together in a sticky tendril-like mass; this material is said to have a sweet taste. Water also aids in dissemination of spores of cherry spot disease. The common Stinkhorn (Phallus impudicus) which frequently causes trouble in orchards and gardens because of the bad odor, is chiefly disseminated by flies that feed on the spores. Ergot (Glaviceps purpurea) is commonly carried from cultivated to wild rye and other grasses, by common flies which feed on the honey dew stage (Sphacelia) of the fungus. Gardiner^® describes how contrivances for assisting plants to maintain them- selves in the struggle for existence are found in fungi and algse; as in the case of Queensland fungus, Clathrus, which has orange red color, strong smelling spores, and is enveloped in a sweet mucilage, thus using the same advertisements, color, scent, and sweetness, employed in higher plants. The mildew of alder has hooked fruits, which are possibly carried about by tiny Acari. Spores are shot out with some force from the mycelial filaments of the fungus that attacks flies. The spores of Sclerotinia Vaecinii have an al- mond smell, and are gathered by bees with pollen, and conveyed from one plant to another. The influence of insects in carrying diseases is well illustrated in the com- mon lima bean mildew (Phytophthora phaseoli). Dr. Sturgis®® calls attention to the structure of the flower of the lima bean and its adaptation to cros^ pollination. The insects (bees) that pollinate the flowers are largely respon- sible for conveying the disease. Dr. Sturgis says: “Further investigation confirmed this view. I have called attention to the enclosed and protected position occupied by the pistil; this obtains until the flower is visited by an insect of considerable size, generally a honeybee. The projecting wing-petals offer a convenient landing place, and, as the bee alights on them, his weight deflects both wings and keel, the style is protruded from the keel, the bee’s abdomen brushes over it, and in his efforts to reach the bottom of the flower the petals are forced apart, the base of the ovary exposed and the bee’s head comes in contact with it. Thus cross-fertilization is secured, but if the bee has, by chance, touched a mildewed pod with either head or abdomen, fungous infection no less surely occurs. It will be noted that the only portions of the pistil touched by the bee are the base of the ovary and -®Miss Estelle D. Fogel Rep. la. State Hort. Soc. ^1:105. 1907. 2®Gardiner Abstr. in Nature. 41:91. soRot. Gaz. 25:192. 48 IOWA ACADEMY OF SCIENCE the style. An examination of scores of flowers showed that in the majority 0^ cases they were infected, and in these cases, without exception, the points of infection were identical with the spots touched by the bees.” Fungi Spread 'by Other Animals. The spores of many fungi pass uninjured through the digestive tract of animals. It is probable that some of the spores of corn smut may pass the digestive tract of herbivorous animal uninjured, just as corn and other cereal grains often do. Corn smut is more resistant to heat than corn is; it is probable that the digestive juices will not entirely destroy the spores of corn smut. The spores of many fungi are accidentally carried by insects by attaching themselves to the body of insects, birds, or other animals. Birds like woodpeckers may convey many wood fungi by opening holes in trees; the same is true of boring insects. In a disease of cotton studied by one of us in 1889, it was shown that mice and other rodents scattered the sterile mycelium of the Oozonium. Fungi Scattered by Explosive Properties. Many fungi have explosive prop- erties but there are few of these among our cultivated crops. The Morchella, or Morel, forcibly ejects its spores ; so too, the cup-fungus, or Peziza, from which the spores are ejected; the Polyporus and various wood-fungi, and the Agaricus and other mushrooms, scatter their spores iir the same manner. Fungi Spread by Farm Tools. The pruning knife may be the cause of the spread of many diseases like pear blight. A knife used for cuttings when in contact with a contaminated soil may frequently contaminate many cuttings as in the Botrytis disease of the House Geranium. Farm implements used to cultivate the soil may spread many root diseases as shown by one of us in connection with the root-rot of cotton and other root diseases of the orchard and garden. The number of instances of such diseases might be multiplied. SOIL MOISTUEE AND FUNGUS DISEASE. Asparagus Rust. Regarding infection Prof Ralph E. Smith^^ makes inter- esting observations. After the statement that the marked freedom from rust of two seasons was due to unusual rainfall, he says; “In the dry seasons dnd upon the drier soils lack of moisture unquestionably reduced the vitality of the asparagus plants. Consequently they become more susceptible to disease and suffered in inverse proportion to the amount of soil moisture available.” The observations of Mr. Sirrine®^ led to the conclusion that the relation of atmospheric moisture in the form of dew or fog is the most important factor of this nature in the development of asparagus rust. Stone and Smith®® found a difference in the prevalence of the disease accord- ing to the moisture retaining properties of the soil, the trouble being worse upon the drier soils. Celery Root Rot. Mr. J. N. Hook®^ found that a serious root rot of celery in Ohio was caused by a species of rhizoctonia. The disease appeared in soils in which celery had been grown for several years and the diseased spots seemed to occur where the ground was lower or not well drained and the soil condi- tion seemed to be largely responsible for it. siBot. Gaz. 38:19-43. Bull. Cal. Agr. Exp. Sta. 165:51-58. 32N. Y. Geneva Exp. Sta. Bull. 188. 33Bull. Mass. Hatch Exp. Sta. 61. Ann. Repts. Mass. Hatch Exp. Sta. 12, 1.), 15. 3^Cir. Ohio Agri. Exp. Sta. 72:6. IOWA ACADEMY OP SCIENCE 49 Grain Rust. There is every evidence that rusts, in particular Puccinia graminis and P. coronata are more common in very moist soils than in drier places. We have observed rust very severe in low fields, when on adjacent and higher ground there was less rust. The poorly drained fields always suffered more than the soils well drained. Mycological literature is abun- dant on this point. WEATHER AND FUNGUS DISEASES. The weather refers to the state of the atmosphere; it has reference to degrees of warmth, cold, moisture and drought. Certain conditions of weather are often responsible for wide spread epidemics of plant diseases. Where the organic matter of the soil undergoes rapid disintegration accompanied by humid, warm conditions the small grains are affected with rust. The warm humid conditions always lead to the attacks of downy mildews. Cool weather though accompanied by frequent rains is not conducive to the severe attacks of rust. Dr. Halsted^® reports that after an early spring of unusual cloudiness and precipitation in New Jersey in the year 1898, the hollyhock rust was very abundant and destructive; cedar apple fungus of great frequency; exoascus remarkably abundant; peach curl never before so wide-spread. The years 1891 and 1892 were dry ones in which there was no outbreak of fungous troubles; the year 1894 had a dry summer. The year was remarkable for a most widespread and destructive fire-blight. The month of May had unusual precipitation followed by a superheated period of ten days. Then came the blight, which seriously affected all pear orchards. In the same year cherry leaf spot disease are unusually abundant. The year 1896 was dry, with June and July rainy. During this time asparagus rust spread in Eastern United States to an alarming extent. Dr. Paul Sorauer®® in a discussion of the problems connected with the sensitiveness of plants with regard to parasitic fungi, notes that the attacks are due to the injuries of frost, etc., and that frost is one of the most potent factors in connection with the attacks of fungi. Plants that are variously colored or blanched are much more subject to diseases than the green plants. This writer considers that it is important to consider plant hygiene, to prevent disease by culture and to develop immunity. He states that in the winter of 1900-01, there was little frost in Germany, but from observations made by numerous persons in Germany it was found that where the eastern and the northern winds removed the snow that the plants on such places became more affected with rusts; furthermore that a heavy soil containing considerable moisture when grain was sown early was less subject to rust than other places. An experiment made with rye indicated that when the moisture is too great and the temperature too high that the plants were affected very much as with frost. Dr. A. B. Prank®^ in a paper on the subject of rusts gives as the character- istic influences of this disease the following; “That the spores of the rust ^^The Influence of Wet Weather upon Parasitic Fungi. Bull. Torr. Bot. Club. 26 : 381-389. 3®Mitt. d. Deut. Landw. Gesellsch. 1900 :185. ®^Nachrichten a. b. Klub d. Landw. 1898:388-389. 4 50 IOWA ACADEMY OF SCIENCE germinate readily only when they have been submitted to the atmosphere for the winter; that saltpeter fertilizer favors the development of rust. He cites- the experiments conducted in 1894 which was very favorable to rust, to show that varieties from American, Indian and other foreign sources, are parti- cularly subject to rust. The investigation carried on by the German Agricul- tural Society since 1892 shows that hybrids of the square head were a little subject to the disease and varieties like Dumel were comparatively free from rust. Eccoasceae Influenced hy Weather. Plum pocket (Exoascus pruni and E. communis), Peach curl {Exoascus deformans) are excellent illustrations of fungi influenced in their development by meterological conditions. Peach curl was destructive in Southern Iowa where peaches are grown; in 1907 many correspondents reported it as destructive. In 1908 there was little of it. Some trees in the vicinity of Ames showed much of it in 1907, the same trees in 1908 had none of the fungus. Puffed branches or plum pocket {E. communis) was abundant in 1907 in many parts of the state. It was also reported in 190& but not nearly as destructive. The curl on oak was also common in places in this state in 1907. The season of 1907 will show somewhat unusual conditions. May was unusually cool with late frosts. These conditions seem to be very favorable for the development of these fungi. The senior author of this paper during the present season has had unusual opportunities for studying several of the Exoasci in the Rocky Mountains, from Eastern Colorado to Utah. In all of these places the Exoasci were abun- dant. The leaves of the Rocky Mountain oak {Quercus undulata) were much diseased at all points visited, Colorado Springs, Palmer Lake, Placerville,, Colorado, Salt Lake City, and several other points in Utah. The Exoascus cerasi on Prunus Yirginiana and P. Pennsylvanica was also abundant in Colorado and Utah. Hundreds ®f leaves were puffed out. One of the most destructive parasites is the Exoascus on the hard Maple {Acer grandidentatum) ; near Logan every tree had nearly all of its leaves spotted from the effects of this fungus. The forests looked blighted. Another common fungus is an Exoascus on the Quaking Aspen, which was common in parts of Colorado. The conditions in the mountains are unusually favorable for the develop- ment of these fungi. The evenings are always cool and the spring backward. It is not unusual in spring and early sjimmer for frosts to occur. The disease appears earlier at lower elevations and later at higher altitudes. January February . March April May June July August — . September October November December , Temperature in degrees Precipitation in inches 1907 1908 Normal 1907 1908 Normal 27.9 24.4 23.5 1. .52 1.12 34.9 27.4 24.7 .84 .86 1.18 40.7 37.5 33. .97 .52 1.61 43. 44.2 44.2 1.99 .9 1.99 47.1 49.1 '52.9 2.37 2.19 1.86 58.1 59.1 61.4 1.16 .96 1.54 66.2 65.6 65.6 2.40 2.6 1.96 64.5 65.1 2.13 2.07 57.5 58.3 57.7 5.75 3.35 5.71 49.1 43.1 46.1 .89 5.97 1.16 33.4 34.3 .37 .57 25.9 25. 1.02. .95 IOWA ACADEMY OF SCIENCE 51 Mr. W. A. Orton speaking of the epidemic of wheat rust for the year 1904 says : “Wheat rust (Puccinia graminis) this year, 1904, caused very general damage over the whole country, due to the humidity of the atmosphere in the latter part of the growing season, and to lateness of the grain in maturing. In the spring-wheat states of the Northwest the loss from rust was 25,000,000 to 40,000,000 bushels, worth at least $25,000,000. In many instances the rusted fields were never touched hy the harvester, and over wide areas the yield was ■only four to five bushels per acre. The western winter-wheat states also suffered severely, and rust was bad as far east as Indiana and Ohio, though not severe in Maryland. The durum varieties introduced hy the department proved notably resistant, though the season brought out great variations in rust resistance even in this group. M. A. Carleton^*®, of this Department, has published further results of investigations into the life history of this and ..several other species of rust.” The weather conditions for 1904 are included in tables and maps accom- panying this paper. Mr. James Berry reports that the season of 1904 in the Upper Mississippi Valley to the Atlantic Coast was generally backward, although the average temperature for the month was generally in excess of the normal. Spring wheat seeding was well advanced over the southern part of the region, by the 7th and 8th of April. Severe rains and snow occurring. The next week, April 18th, was unseasonably cold and germination was retarded. There was considerable snow in the upper lake region during the latter part of the week and considerable frost occurred. Spring wheat seeding was nearly finished in Iowa, Nebraska, southern South Dakota. Little had been done in North Dakota and Minnesota. The week ending April 25th there was freezing temperature throughout the Central Valleys, lake region, New England, and the Middle States. The week ending May 2nd was cool and unfavorable for growth. The week ending May 9th was more favorable. The spring wheat early sown was making good growth. The week ending May 16th as much too cool, with Irosts. The week ending May 23d was more favorable except for frosts on the 16th and 17th in the lake region and upper Mississippi Valley. The fol- lowing week. May 30th, there was excessive moisture from Iowa to Missouri and Oklahoma. The crop of small grain was promising. The week ending June 6th there was excessive moisture and lack of sunshine. The week ending June 13th had unfavorable temperature with too much rain. The outlook for oats was promising. The week ending June 20th continued cool, east of the Mississippi was unfavorable but westward more favorable. The upper Missis- sippi Valley states suffered from extreme moisture. Rust reported from Ne- braska and Iowa. The week ending July 4th was unseasonably cool and un- favorable for rapid growth. On July .11th the weather continued unseasonably cool. Rust reported from Minnesota and Dakota. The week ending July 18th was favorable except in some districts where there was too much rain. The week ending July 25th, too cool with lack of sunshine. The week ending August 1st reports of rust from the spring-wheat section of the country very pronounced. A similar summary for 1900 will show that changeable weather with a great deal of rain and late frost greatly influenced the appearance of rust. ®®U. S. Dept. Agr. Yearbook. 1904 :5 63. 52 IOWA ACADEMY OF SCIENCE The Downy Mildews. (Peronosporeae) . This group of fungi has been studied more carefully with respect to meteorological conditions than any other kind. The years 1895, 1903 and 1905 were particularly favorable for their development. It will be seen from the weather conditions that we had during growing a great deal of moisture accompanied by high temperatures. The year 1903 will be remembered as very destructive to the potato. In addition to the potato rot fungus {Phytophthora infestans) the grapevine mil- dew (Plasmopora viticola) was abundant. Prof. Guy West Wilson whose work on the Peronosporales, for 1907, has been noted in another place, says: ''Plasmopora Halstedii (Parlow) This species was first observed July 29th in the vicinity of Greencastle, Indiana, where a few infected leaves were found on one or two plants on Bidens frondosa. By August 13th the fungus was fairly abundant in this locality and by the 27th of that month scarcely a plant remained uninfected in all the Indiana localities visited. The infection was as complete as any seen during the season, all the leaves being affected and the lower ones killed outright, but no oospores were found. A sihgle clump of Erigeron annuus was also found infected.” This species was common in Ames in August and September. "Plasmopora viticola (B. & C.) This species was quite abundant on both wild and cultivated species of Yitis when they were first examined in July. Conidia were collected on leaf, petiole, tendril, and young twigs. In some vineyards the disease was respon*. sible for heavy loss of fruit but none of the diseased berries were examined for oospores. Among the twelve specimens collected one was upon seedlings of cultivated grapes.” The Grape Vine Mildew was abundant in Ames and in northeastern Iowa in June and July. It was not abundant later in the* season. Spring shoots of the wild grape were badly diseased. Premia lactucae Regel. Mildew of Lettuce. Prof Wilson states that this fungus was “collected on Lactuca canadensis in Hamilton and Putnam counties, Indiana, between July 23d and August 3d. All this material had the appearance of being quite old and indicated that the conidia had been produced for some time past. Of the three specimens collected none contained oospores.” It was abundant on wild lettuce in June in the vicinity of Ames, none, however, was observed on the cutivated lettuce. Peronospora alta Fuckel. Prof. Wilson did not report it as common in Indiana, but it was abundant in Ames in June in 1907, where thousands of leaves were diseased. It was not abundant in Ames in 1908. Peronospora parasitica (Pers.) Fries. Downy Mildew of Mustard. This fungus was abundant during the month of May and June, 1907, in Ames, later appearing on other hosts. It was not common in 1908. Prof. Wilson says concerning this fungus: “During the early spring in New York this fungus attacked great numbers of seedlings of Lepidium virginicum but soon run its course. The previous summer the fruiting and infiorescence was frequently destroyed during mid- summer, but this season no such attack was noted oefore reaching Newark, Delaware, where the fungus was evidently just making its appearance. The same host was found sparingly affected in Indiana. Here a single clump of IOWA ACADEMY OP SCIENCE 53 Brassica nigra and a single bed of Raphanus sativus were found infected. No very robust growth of the fungus was observed this season. Of the five speci- mens (N. Y., one; Del., one; Ind., three) examined the only oospores found were intermingled with those of Alhugo Candida on a pod of Raphanus. Regarding Grape Mildew, Parlow^® says, “The fungus, like all the other species of the genus, flourishes best in moist warm weather, but seems more tolerant of dryness than any other Peronospora with which we are acquainted.” To quote from the paper of Mr. Guy West Wilson^®: “Two important and interesting problems in the history of Peronosporales are (1) the interrelation of meterological conditions and the abundance and development of these fungi and (2) the location of centers of seasonal distribu- tion. These problems necessitate a series of observations extending over a term of years in a given locality and at the same time require the co-operation of observers in localities widely separated in space and climate. A phase of the subject has been treated by Drs. Orton and Selby in their investigations of the centers of seasonal distribution. These observations have been confined almost entirely to economic species such as Pseudoperonospora cuhensis and Phytophthora infestans. From these studies on the first species the oospores which have so persistently eluded the collector it appears that this spore form may be elided or only produced at irregular intervals as a means of rejuvenation. The fungus is perennial in Florida and from this center is carried northward by the conidia each season. From a study of Peronospora in Iowa in 1887, it appeared that the species are suited to a moist season. In general the mildews were found in early spring and after this through the long dry summer, in limited quantities upon plants growing in damp places. During the season from March to August had only 8.32 inches of rainfall. The Powdery Mildews are much more abundant in a comparatively dry season than in a very moist season. For this reason the Powdery Mildew of the Lilac, Cherry, and Grape are much more common in Iowa during the latter part of the season than during the early part. The years 1895, 1899, 1901 were noted for the abundance of Powdery Mildews. Dr. Halsted^^ in a discussion of the relation existing between late fall and potato rot, states that in 1897 and 1899 were two seasons particularly destruc- tive so far as potato rot was concerned, in the eastern states. In 1897 the out- break of potato rot was very unusual and carried away the larger part of the potato crop. He gives the following table: Year _ ___ 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 Av. Rainfall 3.50' |l0.19 5.62 5.30 4.03 2.72' 1 1.66 4.24 5.50 11.42 5.42 He states further that the fungus disease was not destructive in 1889. “It seems to me that the Phytophthora or late blight is quite dependent upon an abundance of moisture in midsummer, and if this relation is noted sufficiently the time may come, it may be predicted with reasonable certainty, that a wet the American Grape-Vine Mildew. Bull. Bussey Institution 1876 : 415-425. ^oGuy West Wilson. Notes on Peronosporales for 1907. Proc. Iowa Acad, of Sci. 1908:85. «Torr. Bot. Club 25:161. 54 IOWA ACADEMY OF SCIENCE July will mean a decaying potato crop, unless some successful method of checking this rapidly developing fungus is employed, and contrariwise, a dry midsummer will insure freedom from its ravages. The Potato Rot fungus {PTiytopJitJiora infestans) was' abundant in Iowa in 1903; along with this mildew many of the other downy Mildews were common like Downy Mildew of the Grape (Plasmopora Yiticola) destrowing many of the young shoots and even berries of such grapes as the Noah, Yitis riparia, Lindley, etc. The Sunflower Mildew {Plasmopora Halstedii) was abundant on many com- posites like the Sunflower, Boot Jack and Marsh Sunflower {HeliantJius) . The years 1900, 1902 were unfavorable for the development of these fungi. These conditions are best shown by the conditions of the rainfall brought out in tables accompanying this paper. Mr. Norton^^ says, in speaking of late blight of potato, “This disease is not commonly destructive in Maryland, as the summer temperature is not usually sufiiciently low for a time long enough for the development of the parasite, though it has caused serious loss in many parts of the United States since 1840, and has been destructive at times as far south as Florida, being no doubt introduced on northern seed.” Fusicladium and Monilia. H. Mueller-Thurgau^® in a paper on the Monilia Dis- ease of branches of Drupaceous Fruits, attributes the epidemic in Switzerland, of that year, to the cold days of March, 1900. In other words the frost was partly responsible for this disease in that branches became less resistant to the Monilia and allowed the fungus to enter easily. Rudolph Aderhold^* in a discussion of the development and life history of the relationship of Cladosporium and Fusicladium spores, and the causes that lead to infection thinks that the most favorable temperature for the germina- tion of Fusicladium pyrinum is +2° C. and germination is very energetic at 11°. The optimum. temperature of the same is 22°, but beyond this there is a rapid decline. Therefore the warm days of spring appear to be especially favorable for the germination of the spores of Fusicladium. The spontaneous appearance of Fusicladium is dependent largely upon the character of the weather, especially moisture, frequent rains are favorable. SOME FUNGUS EPIDEMICS. Mildews. It may be interesting to note here that in some years certain species of mildews are particularly destructive to certain host plants. Salmon^® states that the mildew of the cultivated hop sweeps in epidemics over some of the European countries in certain years, not appearing in inter- vals between. Mr. David Griffiths records an interesting observation of the occurrence of fungi. Beginning with 1892 E. communis was not found on Polygonum, a new host, in South Dakota until 1895, when some immature specimens were found in the northern part of the state. The following year it was more frequent and two years later abundant everywhere. Doubtless the fungus occurred in small quantity, though unobserved, previous to 1896. ‘‘^Norton, J. B. S. Irish Potato Diseases. Bull. Md. Agr. Exp. Sta. 108 ;69. ^^Schweiz. Zeitsch. f. Obst-Und-Weinhau. 1900. Centralb. f. Bact. u. Par. 2 Abst. <6:653. -^Landw. Jahrb. 29:541-587, pi. 9-12. «Torr. Bot. Club 9: 11. IOWA ACADEMY OF SCIENCE 55 During the present season 1908, we notice with particular severity and abundance the powdery mildew of the catalpa, plum, and cherry. The common powdery mildew of the knotweed has been particularly abundant here for a number of years and this season forms no exception to the rule. Rmts. The Ash rust was reported by Dr. Bessey as abundant in Iowa in 1884. The same year it was observed in La Crosse, Wisconsin. Since then it has not appeared in these neighborhoods in epidemic form. There must have been a great deal of the teleuto stage of the rust. The Puccina pruni-spinosa was common in 1889 on a variety of Prunus Americana, the Chippeway in Ames and since has rarely been seen. Clover Rust. Clover rust upon red clover^® was not observed in Iowa until August, 1900, and then upon the “aftermath.” Later it was found quite abundantly on the College Farm, the diseased plants being seriously affected. How long the fungus has affected red clover plants in this country and in Iowa is not known, but it is reported on white clover by Arthur in 1884 and was common on this host in Wisconsin in 1883. HollyhocTc Rust. The hollyhock rust, native to Chili, was introduced into France in 1872, and in a short time became general in Europe. It found its way to this country in the year 1886, having been reported from Beverly, Mass. Prof. Farlow^® records its earliest appearance in the United States. Holly- hocks in the garden of Prof. C. L. Jackson were found to be affected with the disease which was introduced with the seeds imported from Europe. In 1887 it appeared in the Boston Public Garden. A few years later in 1891 it was re- ported in New Jersey and New York. This was reported by C. E. Hunn^'^ in New York in 1889. The writer found it common on the Pacific coast in 1898. This disease has played havoc with hollyhock culture in some parts of the United States. Asparagus Rust. The Asparagus rust, native to Europe, was unknown to this country prior to 1896, when it was reported in the east. Halsted^® and R. E. Smith^® think that the rust started in an epidemic from the North Atlantic states during the fall of 1896. It is now a most destructive enemy to the culture of this plant. Downy and Powdery Mildews. The Downy Mildew of the grape was un- known in Europe before the introduction of the American grape vines to resist the attack of the Phylloxera. Mr. Salmon gives an interesting account of the spread of the gooseberry mildew in Europe which he thinks may be due to importation of American plants. The potato rot fungus infestans) was unknown to the botan- ists of Europe before 1845. This soon spread to many of the European coun- tries playing havoc with the culture of the potato. Apple Blight. Apple and pear blight was practically unknown on the Pacific coast until a few years ago. It was unknown according to Ralph E. Smith®® in central and northern California but it had wiped out the orchards in the south- ■‘“lowa Agr. Exp. Sta. Bull. 13 ; 5 1-5 3. «Parlow, W. G. Bot. Gaz. ii:309-310. disease of the Hollyhock. Rep. N. Y. Agr. Exp. Sta. 1890:335. ^®The asparagus rust ; its treatment and natural enemies. New Jersey Agr. Exp. Sta. Bull. 129:3-20. ^^Asparagus and asparagus rust in California. Cal. Exp. Sta. Bull. 165:5-99. Rept. of Plant Pathologist July 1, 1906. 50Univ. Cal. Exp. Sta. Bull. 184 :221. 56 IOWA ACADEMY OF SCIENCE ern part of the state. This shows that when the source of infection occurs that a disease may become troublesome and serious. Clasterosporium. Rudolph Aderhold^^ calls attention to the Clasterosporium carpopMlum which is especially destructive to cherry leaves in Germany, and that the same attacks the younger leaves more readily than the older. IMMUNITY AND DISEASE-RESISTANT VARIETIES. Acclimatization. In general acclimatization is the best dependence for im- munity from fungus diseases. A plant thoroughly acclimated is more disease- resistant than one not acclimated. Corn brought from tropical countries and cultivated in Iowa has a strong tendency to become affected by both smuts and rusts. A case of the kind was referred to by one of us'^^ on some corn from the Philippine Islands, a number of years ago; every ear was affected with smut, many nodes likewise containing the same fungus. A variety of Texas rust-proof oats^^ when grown on the College Campus was found to be more seriously attacked than acclimatized varieties. During the past few seasons, Mr. Burnett, has had under cultivation a large number of varieties of oats. Invariably the varieties not acclimatized were more subject to rust than other kinds. The Garton oats, well known for valuable qualities, when grown in cooler climates produce smaller crops on account of rust; after having been grown tw^o or three years in this country they are less subject than when first imported. Such acclimated varieties as Early Champion and Khersoen are much freer from rust than the non-acclimated varieties from Europe, the north or from the mountainous districts of our country. Prof. Bolley^% commenting upon the stableness of varieties states: “Though I have worked with many varieties and strains of wheat, flax and potatoes and ha(Ve found them all reasonably stable if given generally stable environment, I have never yet been sure that I have seen a stable plant or a stable strain or variety. Some change is continually taking place and any change I think, may be fixed just in proportion as we know the conditions which originate it.” Prof Bolley says®'^: “The North Dakota Experiment Station has had a very marked success in breeding and selecting flax with a view to gaining resistance to wilt and rust; indeed it has largely solved the problem so far as breeding for resistance in seed crop is concerned.” The work in selection of Clover resistant to Collet otricliiim trifoUi, by Bain and Essay®® resulted in a decided reduction of the disease. Of sugar-cane in Hawaii, Mr. Cobb®h says, “The chances seem distinctly to favor the ultimate securing of resistant varieties that are also highly pro- ductive.” The Le Conte pear succeeds best in the Gulf Coast and Southern Atlantic regions being quite free from blight, more so than Kieffer pear. '^iLa.ndw. Jahrb. 30:771. Biedermann’s Centralb. Agrikultur cliemie 32:23. ®2Pammel, L. H. Monthly Review of the Iowa Weather and Crop Service. 2:9, ^spammel, L. H. Fungus Diseases of Iowa Forage Plants. Pro. Iowa Acad. Sci. 1:93. =54Rept. Am. Breeder’s Assn. ^ 1908: 125, 128, 129. s^Rept. Am. Breeder’s Assn. .4 1908: 228. s®Bull. Tenn. Agr. Exp. Sta. 75. ®"Cobb, Some Elements of Plant Pathology. 43. IOWA ACADEMY OF SCIENCE 57 With regard to blight of pears Waite®® says, “The thrift that makes a tree bear good fruit also makes it susceptible to blight. Check the tree by with- holding tillage so that it makes a short growth and bears small fruit and it will be in a better condition to withstand blight than it would were it culti- vated.” Borne Resistant Varieties. Some varieties of apples have been found to be more resistant to rust than other varieties; Oldenburg, Hibernal, Pameuse and Canada Baldwin in Iowa®® are more or less resistant. In observations with rust of the apple, the Mercer County crab was found to become affected by the Gymnosporangium macropus, while the Russian va- riety Tetofsky on which it was grafted, was free. Within recent years wide infection has resulted to the Wealthy apple from proximity to the Cedar apple fungus on cedar trees. Duchess and its type are quite free from apple scab; Wealthy is quite generally affected. The Early Richmond and Montmorency cherries are very subject to leaf -spot iCylindrosporium padi). Immunity from One Disease Caused Tjy Presence of Another. Regarding peculiar conditions obtaining in the relationship of fungus and host, Dr. Hal- sted®® observes that one fungus develops in the host immunity from another. The rust Puccinia mamillata while common upon the ordinary plants of the climbing smartweed {Polygonum dumetorum) was nearly absent from all in- fested with Ustilago anomala. It would seem that the smut had taken posses- sion of the plant and the latter did not longer furnish the proper feeding ground for the rust. The same thing was found to be true with smutted specimens of Panicum sanguinale, the leaves of which are rarely affected with Piricularia grisea, while the normal plants have foliage spotted with it. Transplanting. Burchard®^ calls attention to the fact that the American clover when grown in Europe, in spite of its more hairy character is more sub- ject to mildew than the home grown varieties. Boil Conditions as Affected by Manures. Emil Laurent®® found that the same variety of potato on which different fertilizers had been used showed dif- ferent conditions for bacteriosis. Nitrogenous and potash manures made the potatoes more immune toward Bacillus coli communis of artificial infection. The author thinks that the ability of a potato to resist bacteriosis rests upon the ability of the cells to produce soluble cell substances whose strength is utilized by alkaline conditions. Toxin. Miss C. E. Marryat®® states that a very susceptible variety of wheat was cultivated to study the effect of immunity the germ tube entering readily by means of passing through the stomata. In the case of a resistant Einkorn the germ entering through the stomata but in a short time the hyphse began to break up. The author suggests that immunity is due to the production of a certain toxin or antitoxin. BIOLOGIC SPECIES. Biological experiment with fungi is of great importance and considerable work has been done of recent years with the biologic species of rust and mildews. ^sWaite. Report U. S. Dept. Agr. 1895:299. '^'’Pammel, Cedar Apple Fungi and Apple Rust. Bull. Iowa Agr. Exp. Sta. 84 :36. ®0Mycological Notes IV. Bull. Torr. Bot. Club. 26:12-20. ®iLandw. Wochen. bl. f. Schleswig Holstein 51 :34. ®-Ann. De I’lnst. Pasteur 1.3:1. Centralb. f. Bakt. .u. Par. 2 Abst. 5:685. ®3Jour. Agri. Sci. 2:129. 58 IOWA ACADEMY OP SCIENCE During the summer of 1908 there were placed under observation in the greenhouse, plants of the following grasses: Lolium perenne, Phleuwi pratense, Poa pratensis, Agropyron repens, Panicum crus-galU. Bromus secalinus, Setaria glauca, Dactylis glomerata, and Hordeum jutatum. Wheat plants bearing abun- dance of ErysipUe graminis were placed in contact with the leaves of these plants, none of which became affected by it. Prom the work of Salmon®^ it appears that different forms of bpTiaerotheca humuli occur upon Pyrus Aria, Potentilla, and other hosts, these forms having individual characteristics. “While these forms present slight morphological differences, these are not sufficiently marked to prevent the forms being con- sidered as belonging to the species.” Dr. Salmon®® experimented with mildew of Erysipfie graminis. The form found on wheat will not normally infect rye; but when the leaves of rye were injured by cutting or bruising they could be infected by the fungus from the wheat. Dr. G. M. Reed who has carried on a series of experiments with Erysiphe cichoracearum^^ D. C. has shown quite conclusively that the fungus “occurs on at least eleven species of the cucurbits belonging to seven genera, infection occurring in these cases in fifty per cent or more of the trials. Only three species belonging to two genera are entirely resistant to the mildew.” It is evident also that this fungus will produce the mildew upon other forms of plants. In the record by Dr. Reed out of fifty-four leaves of common plantain inoculated with Erysiphe cichoracearum from squashes ten were affected. The sunflower was likewise infected in 35 per cent of the trials, but he failed to inoculate mildew of cucurbits on asters and goldenrod. Mr. Griffiths®^ . observes that while the favorite habitat of E. cichoracearum appears to be on the composites, it is not confined to this group. The entire absence of the fungus on hosts which are generically related, is therefore a matter of surprise. Mr. Griffith observed such a case in a garden where three species of Artemisia, A. Ludoviciana, A. tridentata, A. longifoUa, grew in pro- fusion, and in closest proximity. A. Ludoviciana was loaded with E. cichorace- arum, but search failed to find it upon the other two species. No positive reason can be given for the absence of this fungus on the two species in ques- tion, under such favorable conditions. Although closely related there is much difference in the aromatic principle and the development of trichomes in the two species. A parallel case was observed at Buffalo, Wyoming, where A. dracunculoides and A. Canadensis were grown together. The former had an abundance of E. chichoracearum upon it while the latter was entirely free. Rusts also show peculiar relation to hosts. The Puccinia coronata does not grow equally well on the orchard grass, and on some other hosts on which it has been recorded. The forms of Puccinia ruMgo-vero behave differently on various host plants. The form on rye is different than on wheat. J. Ericksson®® who has made a special investigation of cereal rusts considers that the several forms of Puccinia graminis on different host plants are distinct. ®^Monog-raph of the Erysipliaceae. 56. «•> Annals of Bot. 19 :125. ®®Reed, G. M. Infection experiments with Erysiphe cichoracearum D. C. Separate Bull. U. Wis. 250:341. «'^GrifRths. Some Northwestern Erysiphaceae. Bull. Torr. Bot. Club 26:138-144. ®®Ueber die Spezialsierung des Getreidesschwarzrostes in Schweden und in anderen Landern. Centralb. f. Bakt., Abt. 2.9 :590-607, -654-658. 1902. IOWA ACADEMY OP SCIENCE 59 e. g., P. graminis secals on rye, P. graminis tritici on wheat, P. graminis on Poa. Klehahn®® too has found that some of our rusts must be considered as biologic forms. Demonstrated especially in connection with the aecidial forms of the grass and grain rusts. Carleton™ arrived at somewhat similar conclusions. Arthur'^^ also reports on the restrictive development of some of the species. Freeman’s^'' work clearly indicates as quoted by Reed that the uredospores of barley will infect wheat and rye as well as barley and oats. The uredospores from rye will infect rye, wheat, barley, but not oats. The following record is a summary of the work conducted by this Station since 1892, and the previous work by Dr. Halsted and Dr. Bessey. We have therefore a record of the abundance of fungus diseases in Iowa for nearly twenty-five years. The earlier records, of course, are not so complete as the later records. For use of characters see end of table. Eriksson and Henning Die Getriederoste. Stockholm. 1896. ®®Die wirtswechselnden Rostpilze. Berlin. 1904. . '^oCereal Rusts of the U. S. Bull. Bur. PI. Ind. Veg. Phys. and Path. U. S. Dept. Agrl. 16. ■^^Cultures of Uredineae 1904. Jour. Myc. 11:50. 72Cited by Reed 66. 60 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION OF COMMON FUNGUS DISEASES IN Name of Disease 1870- 1877 1878- 1881 1882 1883 jlSSl 1885 Bacteriaceae— ] 1 Apple and pear blight + + 7 Bacteriosis of potato Peronosporeae— 0 0 (?) - (a) 10 Downy mildew of Shepherd’s Purse 11 DnwTiy mildpw of Ipftiipp . . _ _ _ - - 12 Afillpf flispfisp 13 White rust of radish and Shepherd’s Purse ^ + + Exoasceae— 14 Plnm pnplrpf .. . . .. -H : - - Ip Enlnrgpfl plum branphps Ifi Ppfiph pnrl - i - - 17 Cottonwood curl I Erysipheae— IS Rnsp mildpvv IQ iVTildPw of npplp 2A Pnwflpry milrlpw of phprry - -t- - - - 21 Powdery mildew of grape -1- ’80 ’83 — — 22 Powdery mildeiv of Dooryard Knotgrass 23 Powdery mildew of Tiilae _ _ _ -i- — - — — 24 Powder^’ mildew of pea _ + - - - - 25 Powdery mildew of grass IOWA ACADEMY OP SCIENCE 61 IOWA, FOR THE PERIOD 1870 TO 1908 INCLUSIVE. 1886 1887 1888 1889 1890 1891 1 1892 1893 1894 1895 1896 L897 1898 1899 1900 190'! 1902 1903 1904 1905 1906 1907 ji903 (a) + + + + — — — + + + - - - + — + + - - i j - + + ■ + - - (?) 1 0 0 0 0 0 0 1 0 + 0 0 0 0 0 (a) (a) (a) — — + — — + — — — — — + + — + + — — (&) i 1 (a) (a) (a) — 1 — + 1 ! — + 4- (a) *- ' 1 + 0 — + + — (a) (a)! (a) — + + — + : + j (c) (a) + — + + ^ i + — + — — + 1 + __ ! 4- - + + 0 “ ~ — -1 i + + + — - + + 4- 4- - 0 i i 0 0 0 0 "“1 j . 1 1 + 4- 4- (d) + + 1 _ _ _ _ + + + — (b) 1 + + + + + 1 + — __ 4- 4- I “ ! - - + 1 + 1 - + + - - + + 4- 4- (&) + ' — ~ ~ + + ! — — — 1 + + + + + + + + ■ — 4- 1 (&) ~ , — + + 4- — 4- ' - + - - - ' + ! - - - 62 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION OF COMMON DISEASES IN Name of Disease 1870- 1877 1878- 1881 1882 1883 i 1884 i 1885- Hypocreaceae— - - - Fungi Imperfect! , etc. — 27 Spot disease of strawberry + + 28 Apple-scab 0 - 29 Black-Knot of plum + - - - - 0 0 36 Spot disease of red currant S7 Spnt fIi«pnHA nf ^nnsphprry ... .98 Spf^t dis^as*^ nf hppf , . _ _ .90 Anthrqpnnsp of r.qsphprry __ . .. + 40 Anfhrnptinsp of blaokhprry 41 Spof rlispnsp of Alfalfa . 42 Brown-rot of stone fruits 0 0 4.9 Wbpat spah 44 \Vbpaf blight _ .. _ . 4.T Bird’s-pyp fnngiis . _ ._ 4fi Brown. rot of Sugar Bppt 0 0 47 Spab on phprrv ... _ 48 Scab on plum 49 Spab on ppaph .... 50 Yellow leaf disease of barley 51 Oak-spot Uredineae— .52 Common grass rnst + + - - 53 Covprpd rnst - .51 Crowned rnst on oats_ _. - - - 5.5 Bean rnst IOWA ACADEMY OF SCIENCE 63 IOWA FOR THE PERIOD 1870 TO 1908 INCLUSIVE-Continued, 1886 1887 1888 1839 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 1904 1906 1906 1907 1903 ] - - + — — + + + + (a) + + - + - - - - - + + + - 1 + , + - — _ 0 _ + _ + _ _ _ - + + + + _ 1 _ — _ 1 + + + + + + (?) + + _ - - + + + - + - - + - - + 4- - - - + + + + + - + - + + - - + + + + — (?) + — + + — — + — - + + - — + — (&) + + — - — — + + + + + + + •+ + + ~ + -- + + - + + + + + + (&) + + + + + iQ) — ■ — + + + - + + — (a) — - - - - - - + 0 - + 1 5+ 1 0 + - - + - - + - + - + - - + - + - + + + — ~ - - + + + - + + - - + + - - - + - + + - + + - - - + + - - + - - + + - - .+ + + - + - - + + -- - - + + - - + + 0 + + - 64 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION OF COMMON FUNGUS DISEASES IN Name of Disease 187X)- 1877 1878- 1881 ISS^llSSS 188411885 - - - - - - + + + + + 65 Rust ou ash + + + fifi Rpd rnfft of TflsphpiM’y ... aj Ornngp rnsf of tosp . . .. _ . . finnsphprry rnsf -f Asp.nrngus rnsf . . _ _ -f . . U.stilagineae— 70 Ofit jamnf 71 Whf“Ot smnf (loose). .. . 7'9, Povn smnf + - 7;^ Barley smnf 74 Borlpy smnf (naked) 75 Bnnf of wbeaf - 76 Foxfnil smnf .. . . . ... 77 Sorghum smnf ._. . _. .. . 7S Timofhy smnf .. . . 79 Crab-grass smut 80 Wild rye smut _ SI Afillef smnf .. _ . References: (a) Abundant early in the season. (&) Abundant early in season on cherry. (c) Abundant in the fall. (d) Abundant on seedlings. (c) Common on sugar beet. (/) Common on pepper-grass early in the spring. (g) Abundant on seedlings of cherry and American plum. (h) Abundant on wild apples. (i) Severe locally. IOWA ACADEMY OF SCIENCE 65 IOWA, FOR THE PERIOD 1870 TO 1908 INCLUSIVE-CONTINUED. 1886 1887 1888 1889 1890 1891 1892 1893 1 1891 1895 1896 1897 1898 1899 1900 1901 1902jl903 1904 1905 1906 1907 1908 - + + + ; + + + + - - - - + - -■ - - - - - — 0 0 0 0 0 0 0 0 0 + + + + + + + - + — - - : + + + + + + - - 0 0 0 0 - - - 0 + + + + + + + + + + + , + + + + + + + + + - (i) - - - + - - - - - + - - - - - - + + - - - - - + + + + - -Z- - + — + - - 0 0 + + + + + + + + + + + + + + + + + + + + + + + - + + ■ + + + + + + + + + + + + + + + + + + + + 5 66 IOWA ACADEMY OF SCIENCE SCIENTIFIC NAMES OF FUNGIS DISEASES. 1. Bacillus amylovorus (Burr) De Toni. 2. Bacillus sorghi Burr. 3. Bacillus solanacearum Er. P. Sm. 4. Bacterium campestre (Pam.) E. F. Sm. 5. Bacillus cloacea Jordan 6. Bacillus carotivorus Jones. 7. Septoria ribis Desm. 8. Phytophthora infestans De By. 9. Plasmopara viticola (B. & C.) Berl and De Toni. 10. Peronospora parasitica (Pers.) De By. 11. Bremia Lactucae Regel. 12. Sclerospora graminicola Sacc. 13. Cystopus candidus (Pers.) Lev. 14. Exoascus pruni Fuck. 15. Exoascus communis Sad. 16. Exoascus deformans (Berk.) Puckl. 17. Taphrina aurea (Pers.) 18. Sphaerotheca pannosa (Wall.) Lev. 19. Sphaerotheca Mali (De By.) Burr. 20. Podosphaera oxycanthae (D. C.) De By. 21. Uncinula necator (Schw.) Burr. 22. Erysiphe communis D. C. 23. Microsphaera alni (Wallr.) Schw. 24. Erysiphe communis D. C. 25. Erysiphe graminis D. C. 26. Claviceps purpurea (Fries.) 27. Sphaerella Fragariae (Tul.) Sacc. 27. Sphaerella Fragariae (Tul.) Sacc. 28. Venturia inaequalis (Cke.) Aderh. 29. Plowrightia morbosa (Schw.) Sacc. 30. Guignardia Bidwellii (Ell.) V. and R. 31. Marsonia Juglandis (Lib.) Sacc. 32. Oospora scabies Thax. 33. Macrosporium solani Ell and Mart. 34. Cylindrosporium Padi Karst. 35. Septoria ribis Desm. 86. Cercospora angulata Wint. 37. Septoria ribis Desm. 38. Cercospora beticola Sacc. 89. Gloeosporium venetum Speg. 40. Septoria Rubi Westd. 41. Pseudopeziza Medicaginis Sacc. 42. Sclerotinia fructigena (Pers.) Schw. 43. Fusarium culmorum (W. G. Sm.) Sacc. 44. Cladosporium herbarum (Pers.) Link. 45. Sphaceloma ampelinum De By. 46. Rhizoctonia betae Kuhn 47. Cladosporium carpophilum Thum 48. Cladosporium carpophilum Thum 49. Cladosporium carpophilum Thum 50. Helminthosporium graminum Rabh. 51. Marsonia Martini Sacc. and Ell. 52. Puccinia graminis Pers. 53. Puccinia rubigo-vera (D. C.) Wint. 54. Puccinia coronata Cda. 55. Uromyces appendiculatus (Pers.) Sacc. 56. Uromyces Trifolii (A. and S.) Wint. 57. Puccinia Sorghi Schw. 58. Puccinia pruni Pers. IOWA ACADEMY OP SCIENCE 67 59. Puccinia pruni Pers. 60. Gymnosporangium macropus L. R. 61. Gymnosporangium clavipes Cooke and Peck. 62. Gymnosporangium globosum Park 63. Roestelia pirata Thaxter. 64. Accidium Berberidis Gmel. 65. Accidium Fraxini S. 66. Gymnoconia interstitialis (Schl.) Lagb. 67. Phragmidium subcorticum (Schrnk.) Wint. 68. Aecidium Grossularise D. C. 69. Puccinia Asparagi D. C. 70. Ustilago avenae (Pers.) Jens. 71. Ustilago Tritici (Pers.) Jens. 72. Ustilago Zeae (Beckm.) Unger. 76. Ustilago neglecta Niessl. 74. Ustilago nuda (Jens.) Kell, and Sw. 75. Tiletia foetens (B. and C.) Tul. 76. Ustilago neglecta Niessl. 77. Spbacelotbeca Reiliana (Kuhn) Clint. Sph. Sorghi (Lk.) Clint. 78. Ustilago stri^formis (West) Neissel. 79. Ustilago syntherismae Pk. 80. Urocystis agropyri (Preuss.) 81. Ustilago Crameri Korn. AMES, TEMPERATURE IN DEGREES, AND PRECIPITATION IN INCHES, FOR YEARS 1907 AND 1901— A COMPARISON OP A DRY YEAR WITH A WET YEAR. Month 1907 1901 Temperature in degrees Precipi- tation in inches Average tempsr- ature in degrees Precipi- tation in inches Max. Mean Min. January _ 28. 19. 10. .73 23.6 .57 February 36. 25.7 15. .55 18. .9 March 51.5 40.7 42.7 .27 34.4 1.64 April _ 54.2 42. 29.8 .67 49. 1.82 May 67. 53.4 40. 3.54 61.4 3.69 June 77. 64.9 52. 3.26 74.4 2.36 July 76. 69.3 55. 5.32 83.3 2.26 Au^st 85. 66.5 48. 6.15 72.8 1.21 September 74. 62.4 50.6 2.14 61. 3.65 October 62.8 49.8 36.6 3.04 53.9 2.98 November 43.6 36. 25. 1.02 37.9 .67 December 38. 29. 19. .83 20.5 .57 Totals 56.9 46.5 41.8 27.58 49.2 22.32 68 IOWA ACAPEMY OP SCIENCE TEMPERATURE AND RAINFALL FOR AMES, 1908. Jan. Feb. March April May 0) a July W) < Sept. d O 1 Not. 1 Dec. Preeipitatinn . . .55 24.8 1.55 24.8 .45 38.1 1 1.94 1 50.4 : 7.95 59.3 3.93 67. 3.63 72.8 j 5.9 69. .5 66.1 6.23 52.4 :::::: :::::: Temperature AMES, MEAN TEMPERATURE IN DEGREES, 1876-1907. Jan. Feb. March! 1 April May June 9 Aug. Sept. Oct. Nov. Dec. I iiinnal Mean 1876 16. 30. 26. 48. i 61. 68. 75. 74. 71. 46. 29. 11. 45.5 1877 12. 33. 26. 48. i 61. 68. ! 75. 72. 64. 49. 20. 17. ' 45.3 1878 23. [ 24. 45. 52. 56. 68. ! 78. 75. 62. 48. 39. 16. ! 48.9 1879 14. ‘ 21. 37. 50. j 63. : 70. : 78. 72. 60. 58. 34. 16. i 47.7 1880 32. 30. 46. 69. 73. ! 77. 75. 61. 47. 24. 15. 1881 8. 16. '277' 43. 69. : 72. ! 79. 77. 66. 53. 33. 31. i 47.8 1882 22. 32. 35. 50. 54. 70. 72. 73. 65. 54. * 36. 19. 48.5 1883 , 3. 14. 29. 51. 55. 68. 76. 70. 44. 1884* 15.9 19.1 35.3 53.2 65.3 76.9 78.1 74.5 59.5 ; 40.1 17.6 ; 42.35 188:5* 10.5 12.5 34.7 51.3 64.2 I 68.1 79.8 74.3 67.7 54.7 43. 29.3 49.3 1888* 11.4 25. 37.3 58. 69.9 ' 78.7 : 86.4 85. 70.9 63. ■ 37.7 17.9 ■ 45.1 1887* 13. 21.2 38.9 60. 73.5 82.3 1 87.3 80.3 . 67.3 59.1 40.9 23.9 53.9 1888 20. 23. 49. 43. 68. 75. 70. ' 80. 47. 28. 1880 21. 18. 39. 50. 60. 67. 1 73. ■ 71. : 61. 47. 32. 37. 48. 1890 18. 25. 28. 54. 58. 73. i 77. 68. 60. 49. 1891 25. 19. 28. 51. 50. ■69. 1 70. 69. 68. 48. 30. 32. 47.3 1892 16. 46. 52. 69. ■ 74. 72. 64. 54. 33. 15. 1893 6. "isr’ H'" 44. 54. I 73. , 79. 72. 68. 55. 36. 22. 46.6 1894 .. 16. ' 17. 39. 50. 60. : 72. ■ 65. 51. 31. 29. 1895 12. i 16. 34. 54. 61. 68. ~7o7' '72?" 68. 49. 32. 25. 46.8 18nfi 65. 70. 72. 56. 47. 30. 31. 1897 17. 25. 32. 48. 59. 69. 78. 70. 72. 56. 34. 15. 47.9 1898 23. 1 23. 38. 49. 60. 71. 73. 72. 65. 47. 37i- 10. 47.3 1899 20.1 18.2 25. 48.6 60.5 ' 70.7 73.2 74.2 62.8 57.2 44.1 21.1 48. 1900 26.4 64.4 69.4 ; 73. 1 76.8 66. 59.8 33. 27.2 1901 23.6 18. ■ 34.4 i 49. 61.4 : 74.4 83.3 72.8 , 61. 53.9 37.9 20.5 49.2 .1902 21.8 15.3 40.1 48.6 64.2 65.6 . 72.8 69.3 i 59.8 52.8 40.8 20.6 47.6 1903 24. 19.6 38.4 49.8 62.3 ; 64.8 ’ 73.4 69.4 60.5 51.6 35.2 ! 20.2 47.4 1904 14. ' 14.9 35. t 45. 60. 67.4 70.2 69. 64.5 53.6 41.3 22.2 46.4 1905 14.0 : 13.5 44. : 47.4 ■58.4 70.4 70.4 75.4 ! 65.7 49.4 38.2 1 28.2 48. 1906 24.8 ! 24.3 27.4 ' 52.7 60.8 68.1 70.6 ■ 73.8 : 66.8 51. 35.7 ! 27. 1 48.6 1907 19. ' 25.7 tO.7 i 42. ‘ 53.4 64.9 ! 69.8 06.5 62.4 49.8 36. 29. i 46.6 Average 15. 22.2 i 33.9 1 49.6 62.4 70.2 75.4 72.8 65.1 52. 35.1 27.1 i 47.4 *Noon readings — not averaged into total. IOWA ACADEMY OF SCIENCE 69 AMES, PRECIPITATION IN INCHES, 1876-1907. Jan. Feb. March! 1 April May June July Aug. Sept Oct. Nov. Dec. Aiiuual Sum. 1876 1.9 .4 2.35 1.50 4.25 4.28 6.50 8.29 '5.14 ' ; .75 1.72 .02 37.10 1877 1.41 1.96 4.43 7.94 ; 3.60 6.48 .90 . 3.14 187S 4.09 3.39 4.35 7.53 5.33 1.95 3.00 1.38 ^35 ! .83 1879 - .43 1.08 .78 1.27 4.46 4.65 .48 1 3.98 2.62 3.34 5.75 1 .25 rio’ii Iftsim 1.25 .52 2.66 3.06 2.37 4.18 6.02 0.34 1.18 1.20 .84 1881 .68 2.50 .94 2.37 2.32 6.70 16.31 3.25 7.63 6.24 2.7 .89 51.9 1882 .57 1.14 3.09 2.44 5.21 7.43 2.66 2.15 .51 3.37 2.17 .98 31.72 188S _ 1.24 1.39 .32 3.55 7.11 . 3.52 6.30 2.92 1.67 2.80 1884 .31 1.12 1.79 3.30 1.80 2.06 4.71 2.50 5.68 4.02 .85 1.86 ; 30.00 1885 .23 .34 .24 3.76 3.69 ! 6.01 ; 4.31 i 9.40 3.64 2.06 .25 .88 33.41 1886 __ _ _ 3.57 .22 .98 3.05 2.78 ! 1.87 .06 .53 4.66 1.11 1.12 .66 20.61 1887 .63 1.44 .66 1.28 .39 I 1.81 2.78 i 1.73 9.77 1.50 .43 .90 22.76 1888 __ 1.08 1.30 2.86 2.25 6.49 3.65 5.15 3.37 .85 1.45 1.90 1889 1.80 .48 T 2.21 4.18 4.90 4.10 .87 2.47 .40 "iTii" .95 1890 1.95 .96 1.20 2.10 4.62 i 5.65 1.85 4.55 3.20 2.38 .10 .85 29.40 1891 2.25 1.20 2.55 1.85 2.25 4.92 3.87 3.35 1.05 2.78 1.95 2.40 30.22 1892 1.00 .30 2.30 4.28 8.86 1 3.74 7.06 : 1.95 .16 1.79 .63 .92 32.99 1893 .28 1.37 1.73 2.42 4.89 1 4.70 2.47 1.08 1.86 .52 .62 1.05 22.99 1894 1.06 1.00' 1.51 4.25 .87 , 3.51 .04 2.10 3.84 ^ 4.71 .45 .61 23.95 1895 .09 .53 .60 4.08 4.28 : 4.69 2.70 4.93 3.93 .47 1.09 1.56 28.95 1896 .44 .25 1.12 4.29 6.18 2.06 9.96 2.24 4.10 2.44 1.21 .37 34.66 1897 1.29 .22 .29 5.70 . 2.68 2.16 2.45 1.48 3.24 1.63 .49 ; 1.56 23.09 1898 .46 1.42 .78 1.52 3.88 7.10 1.10 , 3.30 3.07 6.03 1.40 .54 29.60 1899 .11 .30 .49 2.01 7.23 6.45 1.60 3.70 .89 2.03 1.25 2.35 ' 28.99 1900 .38 .45 2.81 2.61 4.36 6.48 9.14 5.46 7.12 3.73 .51 .19 43.24 1901 .57 .90 1.64 1.82 3.69 2.36 2.26 1.21 3.65 2.98 .67 .57 22.32 1902 1.32 .38 2.70 2.35 6.69 10.01 8.06 7.12 1.66 2.56 1.11 1.87 45.97 1903 .28 1.47 1.44 2.39 7.30 1.33 2.47 7.31 4.43 2.15 .60 .50 31.97 1904 .50 .40 1.63 4.19 3.69 3.45 2.39 i 3.37 3.37 1.78 .02 .79 25.58 1905 .64 .67 2.30 1.33 5.51 4.23 2.14 3.03 2.96 3.55 2.43 .23 29.02 1906 . 1.12 .28 .58 3.16 1.73 3.71 4.06 ■ 5.28 3.14 1.72 1.74 .70 27.22 1907 .79 .55 .27 .67 3.54 : 3.28 5.32 , 6.15 2.14 3.04 1.02 .83 27.58 Average .93 .8 1.51 2.69 4.27 ! 4.36 4.16 6.58 3.39 2.47 1.04 i .96 30.22 70 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION FOR THE UNITED STATES OF COMMON 1900 1901 1902 1 Apple and pear blight -fAlleghany region —Iowa and central -tOhio to N. Dakota 2 Black-rot of cab- bage -fMass. to Ohio -fSouthern Texas —Northern states -f- Texas —Iowa 3 Potato-rot —Atlantic coast states -fPacific Coast -fN. Eng. to Mich. Absent in Iowa, Cal. and northwest 4 Downy mildew of grape -flowa 6 Peach curl -f Eastward ■flowa -tEastward 6 Plum pocket IOWA ACADEMY OF SCIENCE 71 FUNGUS DISEASES FOR THE PERIOD 1900 TO 1907 INCLUSIVE 1903 1904 -1905 1906 1907 +East + Colorado +Ne\v Mexico +Iowa + General + Southern states +Iowa +Paciflc Coast 4- General 4- Ala., Tenn., Pa., 0., Mo., la., Minn., Neb., Utah -fDel., N. J., Md., N. Y., Tenn., Ky., . Wy., Col., Ark., U., Sac- ramento Val. 4-N. J., Md., N. Carolina +N. Dak., Nev. Uncommon —Eastern, central and southern states +Iowa +0., Ind., Gulf States —Iowa 4- general, Del. to Neb., Kan., Mo. to S. Car. 4-Iowa 4-Del., Ind., to Nebraska -fMinn. to Texas -f Vermont -f Arizona +Kan., la., Mo. to Va. and Fla. +Pacific Coast —Southern states —New England (tubers +) +Ohio —Mich., Wis., Fla., Minn. 0 Iowa 4-Me. to Minn. 0 Iowa 4-Fla., N. Y. 4-Long Island 4- Vermont 4- Texas, Va., Col., Md., N. Y., Ver., Me. +Eastern states +Iowa +N. Y., Pa. —Iowa, Minn. -Wis., Ind. 4- Ark., N. Y. —Conn., 0., to Wis. 4- Iowa -N. H., Md. to Neb., Ken., Missouri 4- Iowa +Ky., Georgia —Ver., Ohio —Iowa —Mass., Md., W. Va., La., Delaware +Iowa + Eastward 4-Eastward +N. Y., Pa., 0. —Eastern and middle states -Ala., W. V., N. Y., Ind., Neb., Wash., 4-Ga., Iowa and N. Jersey 4- California 4-N. j., R. I., O., N. York —Del., Ga., N. H., Ind., la., Idaho, Mass. —Iowa —Iowa —Iowa —General -fOhio —Iowa, Neb. —Rhode Island, Vermont 72 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION FOR THE UNITED STATES OF COMMON 1900 1901 1902 7 Black-rot of grape -fEastward N. Y. to Gulf states —Iowa -fMd. to North Car. —Country at large -fR. I. to W. V. and Ohio 8 Bitter-rot apple — Va., Maryland -fW. V., 0., 111., Mo. —Iowa 9 Apple scab -fEastward —Iowa -fCentral and eastern states -f California —Iowa -f Maine to Iowa 10 Early blight of potato -fMd., Ark. -flowa 11 Shot hole fungus of cherry —Country at large -flowa 12 Spot disease of cur- rant and goose- berry -flowa and Neb. 13 Spot disease of beet -f Texas, N. Mexico, Iowa IOWA ACADEMY OF SCIENCE 73 FUNGUS DISEASES FOR THE PERIOD 1900 TO 1907 INCLUSIVE-Continued. 1903 1904 1905 1906 1907 -R. I. to N. Y. +Maryland — W. Va. to Neb. —Iowa +Iowa 0 Lake Brie region +Central N. Y., Michigan —Iowa 4-Michigan -fNew Jersey +N. Carolina — N. Y., Mass., Md., Delaware —Southwest and general U. S. Mo., Ark. to Va. +Md., Va., W. Va. — 0., Ark., Mo. -Va., N. C., Ky., S. Car., Missouri —Mass, and R. I., southward — Ozark s ft — N. Eng. and central states +Wis., la., Neb., Missouri —Mont., Idaho +Bastern U. S. +Iowa —California +Ark., Ind., la., Mich., Neb., Dakota —New York -Pacific Coast —Eastern & cen- tral U. S. —Western states -f Iowa — N. York and Michigan -t-N. H., Maine — Md., W. Va., Virginia west to Arkansas +Iowa - +Mass., N. Y. —Mass., N. Y., N. Eng., Fla., Mich., la.. Neb., Wis. +Northern states N. Eng. to 0. —South +Northerii states N. Y. to Wis. +Iowa +Maryland -W. V., Mo., Kansas () Neb., Iowa +Neb., N. Y., W. V., 0., Fla. —Iowa and Mo. — 0., Ind., la., Nebraska -fN. Y., W. Va., Md., Mo. -F Washington, Ind., Neb. —Mass, to N. Car., Ky., Tenn., Del., 0. Iowa +Io'wa +Iowa, Neb., O. W. Virginia — W. Va., 0. and Iowa -Md., Ky., R. I.. N. J., Neb. Ohio, Iowa —Not prevalent in eastern states — Louisiana 74 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION FOR THE UNITED STATES OF COMMON 1900 1901 1902 14 Antliracriose of raspberry —Neb. eastward 1 +N. Y to Minn. +Iowa +Neb. and Mo. to N. York +Iowa 15 Spot disease of Alfalfa # +New York —Iowa 16 Brown rot of stone fruits +Northern fruit belt —Pacific Coast +N. Y. (cherries) +Conn. and south —Mich., Mo., 111. +Iowa (plums) —Cal., (absent on rest of coast) +Iowa +Northern truit belt (absent on peaches) 17 Wheat scab - 18 Apple rust +Locally, Nebraska eastward 19 Bean rust 20 Asparagus rust +East and south to S. Carolina — S. Dakota, Iowa, Kansas +N. Eng., 0., and westward Iowa IOWA ACADEMY OP SCIENCE 75 FUNGUS DISEASES FOR THE PERIOD 1900 TO 1907 INCLUSIVE-CONTINUED, 1903 1904 1905 1906 1907 +N. Y. and cen- tral states -hlowa -fNew York -flowa -fCentral, west- ern -flowa -flowa -fMd., Mo., Ky. 0., Mich., N. Jersey -fWis., 111. -fOliio, S. Car. -i-Iowa -fNew York -flowa -fCentral, West- ern -flowa -flowa —General —Eastern states -l-Iowa -1- Southern states, Georgia -fMd. plum, nor- thern and cen- tral states —Mich., Ga. —Iowa -fN. Y., N. J., Mo., 0., W., Virginia -R. I., Neb., Mo., Iowa -fFla. to N. J., Ind., Mo., Neb. (on peach) -fGa., Va., Md., Del., 0., N". Y., Mo. and Arkansas —Iowa -fOkla., Ala., Md., Mo. -fGeorgia —Iowa — R. I., Neb., Ind., 111., Tennessee -fNeb., la., Ohio -fNeb., Kan., Mo., Ohio -f Minnesota -fN. Dakota —Iowa —General -f Sacramento Valley -fOhio -flowa -find.. Neb. —Iowa +0., Neb., Iowa -fW. V. to Ga. -flowa —Locally -flowa -Del., Ky., N. J., N. Y., Iowa, Neb., N. Car., 0,, W. V., Mass., Md. -1-Wis., Neb., N. Car., W. Va. +Ind., Neb., N. Car., W. V. 0 Iowa —Wisconsin -fConn., 0., W. Va., la.. New Mexico -Inid., N. J., Pa., Ky., 0., Nebraska -fColorado — N. Car., La., Delaware -flowa — N. J., Mass., Alabama —Eastern and cen- tral -fNeb., Iowa, California -fEastern and cen- tral, N. D., Neb., and Iowa -fEastern -fPaciflc slope — S. Car., 0., la., Neb., N. Dakota -fEastern states -S. Car., 0., la.. Neb., N. Dakota -fPacific slope —General — Iowa -fConn., 111., Col., Mo. 76 IOWA ACADEMY OF SCIENCE COMPARATIVE DISTRIBUTION FOR THE UNITED STATES OF COMMON 1900 1901 1902 21 Red clover rust +Iowa +Iowa 22 Wheat rust —Country at large —Country +N. D., Kan., 111., Wis., Mo., Iowa 23 Oats rust —Iowa —Iowa +N. D., Kan., Mo., Wis., 111., Iowa 24 Barley rust 25 Oat smut —Country at large — N. D. to Kan., Mo., Wis., 111. —Country at large 26 Wheat smut —Country at large — N. D., Kan., Mo., Wis., Illinois —Country at large 27 Corn smut —Country at large — N. D., Kan., Mo.. Wis., Illinois ■ —Country at large IOWA ACADEMY OF SCIENCE 77 FUNGUS DISEASES FOR THE PERIOD 1900 TO 1907 INCLUSIVE-Contincjed , 1903 1904 1905 1906 1907 +New Yoi’k + Michigan +Iowa 4- Iowa -f General 4-Ia., Md., Tenn -Ind., 0., Md., W. Virginia —Iowa —Neb., 0., Md., Mo., Del., N. Y., N. J. —Iowa 4-Wis., 0., Da- kotas, Neb., la., Mo. —Dakotas, Wis., Neb., Iowa, northeast +0., Md., Ind., W. Virginia —Dakotas, Wis., Neb., Iowa, northeast 4-Minnesota —General 4-Iowa -fO., la.. Neb., Minn., Dakotas — Ind., Mont. —Iowa —General 4-Miss. Valley 4-Iowa —General —General — Minnesota 4-Iowa 4-General 4-General -Vermont to la. and Wisconsin +N. C., Ohio —General 4-Wisconsin -l-Washington 4-General -f General +Iowa —General [flowa —General 4-New York 4-0., Texas, Wash., Kan. + General 4-General 4-General —General -f Sacramento Val. and Cal. —General 4-Iowa 4-Locally 78 IOWA ACADEMY OF SCIENCE 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. Bacillus amylovorus (Burr.) De Toni. Bacterium campestre (Pam.) Er. P. Sm. Phytophthora infestans De. By. Plasmopara viticola (B. and C.) Berl. and De Toni. Exoascus deformans Berk. Exoascus pruni Fuck. Guignardia bidwelii (Ell.) V. and R. Glomerella rufomaculans (Berk.) Venturia inequalis (Cke.) Wint. Macrosporium solani Ell. and Mart. Cylindrosporium padi Karst. Septoria ribis Desm. Cercospora beticola Sacc. Gloeosporium venetum Speg. Pseudopeziza medicaginis Sacc. Sclerotinia fructigena (Pers.) Schw. Pusarium culmorum (W. G. Sm.) Sacc. Roestelia pirata Thaxter. Uromyces appendiculatus (Pers.) Sacc. Puccinia asparagi D. C. Uromyces trifolii (A. and S.) Wint. Puccinia graminis Pers. Puccinia rubigo-vera (D. C.) Wint. Puccinia straminis var. simplex Koern. Ustilago avenae (Pers.) Jens. Ustilago tritici (Pers.) Jens. Ustilago zeae (Beckm.) Unger. A.VERAGE TEMPERATURE FOR WISCONSIN, IN DEGREES. March April j May June July Aug. Average 1884 20.9 Average for 28 years 30.1 43.3 4-4.5 57.8 57.6 68.2 67.3 68.7 72.4 67.1 69,6 65.4 61.1 52.4 48.8 1 56.2 56'. 4 PRECIPITATION FOR WISCONSIN IN INCHES. March April May June July 60 9 ◄! Sept. o O Sum, 1884 Average for 28 years 2.31 2.17 4.51 2.28 4.21 3.6 5.41 4.13 8.44 4. 4.3 3.2 4.25 3.21 4.6 2.4 38. 24.9 AVERAGE TEMPERATURE FOR IOWA, IN DEGREES. March April May June July Aug. Sept, Oct. Average Noon Readings— 1884 Average for 31 years 35.3 33.9 53.2 49.6 65.3 62.4 76.9 70.2 78.1 75.4 74.5 72.8 72.7 65.1 59.5 52. 64.7 60.2 IOWA ACADEMY OF SCIENCE 79 PRECIPITATION FOB IOWA, IN INCHES. March ft iq IOWA ACADEMY OF SCIENCE 115 The first series to test the question was planted December 30, 1905. Pot 44 was the check, pot 41 was treated with cattle manure at the rate of sixteen tons per acre, and pot 39 was supplied with mineral fertilizers in amount equal to the plant food found in the manure furnished to pot 41. On March 5, or sixty-five days after planting a picture was obtained of these pots and shown in Plate IV. MANURE vs. MINERAL FERTILIZERS. The same pots were photographed again May 3d, when the clover was 124 days old, with the results as shown in Plate V. THE SAME POTS AT A LATER DATE. A study of these pictures is very interesting. The first picture shows that the manure helped the growth of the clover immensely, while there is very little benefit up to this time from the mineral fertilizers. The mineral fertil- izers had the advantage, too, of being soluble while the manure was largely insoluble. The second picture shows that the minerals have been helping the clover, and this pot is bidding fair to catch up with the manured pot. The check pot also has been growing much better than it did it first. It would seem that there was something in the manure that caused the soil to be a good medium for the growth of clover when it was quite young, but as the clover got older it was able to shift for itself and the mineral plant food helped it some. The stand varied so much in this series that it is difficult to make exact comparisons by means of the green weights, therefore they are not given. Complete description of a later series is given, fully establishing the fact that the manure helped the growth of the clover far beyond the help given by the soluble plant food, and proving that the mineral plant food theory is not a satisfactory explanation of the action of manure on this soil. A fresh sample of soil was secured from the field in October, 1906. The sample was pulverized and mixed as soon as it reached the laboratory and placed in closed cans to keep it as near to field condition as possible. Manure leachings, similar to that used in the last experiment described under the dis- cussion of the physical effect of the manure, were analyzed and found to con- tairf 1.005 per cent solid matter, .65 per cent ash, .02296 per cent nitrogen, .012 per cent phosphoric acid and .05294 per cent potassium. 870 c. c. of the leach- ings, therefore, contained .2 g. of nitrogen. This amount of nitrogen was found by previous experiments to be sufficient for the clover. 870 c. c. of leachings contained .0456 g. of phosphorus and .46058 g. of potassium. The pots 208 and 209 marked N. P. K. were given exactly the same amount of these three ele- ments of fertility. The nitrogen was furnished in 1.212 g. of sodium nitrate, the phosphorus was found in .5271 g. of disodium hydrogen pb-osphate and the potassium in 1.0255 g. of potassium sulfate. To ascertain wjbich one of these elements was responsible for the better growth of the clover, they were also applied separately as is shown by the table. For purposes ff comparison two other carriers of nitrogen were tried, namely dried blood and peptone. .2 g. of nitrogen was supplied to each pot. 870 c. c. of the manure leachings were divided by distillation into two approximately equal portions a distillate and a 116 IOWA ACADEMY OF SCIENCE residue, and these portions applied to two different pots to find which one con- tained the plant food. The series w^as planted October 19th, and harvested January 18, 1907, when ninety-one days old. The following table gives the treatment of each pot In the series, the green weight of the crop when harvested, and the relative weight of the crop on each pot. OCTOBER PLANT FOOD SERIES. o ft 6 Iz; Treatment Green wt. No. plants Relative weight Average 200 Check - - 4.1 101 90 2oa Check 4.4 10 103 100 202 Manure leachings 7.9 10 186 208 Manure leachings __ 0.5 10 223 20'5 204 Distillate from teachings- 4. 10 94 205 Distillate from leachings 4.6 10 108 101 206' Residue from distillate- _ __ _ ___ — _ 10.1 10 237 207 Residue from distillate 8.5 10 200 218 208 N. P. K 7.65 10 180 200' N. P. K 6.85 10 161 170 210 Sodium nitrate -- 4.15 10 97 211 Sodium nitrate _ _ _ _ 5.75 10 135 116 212 Dried blood _ 5.5 101 129 213 Dried blood _ 5.05 10 140 135 214 Peptone _ _ _ _ _ 5. 10 118 215 Peptone _ - 5.45 10 128 123 218 Potassium sulfate _ _ __ 3.65 10 86 210 Potassium sulfate 5.7 10 134 no 220 Sodium phosphate __ __ __ 6.75 10 160 221 Sodium phosphate - _ 5.65 10 133 147 The above table shows that the manure leachings have a relative standing of 205, while the distillate from this made no gain whatever. The residue resulting from the distillation gave as good gains as the fresh leachings. The point is thus proved from two directions that the fertilizing value of the manure leachings were not volatile but remained in the fiask during distilla- tion. The next point is the effect of the mineral fertilizers. This is 170 which is considerably below that found for the manure. What part did the different elements play? Taking the data as it stands, the evidence is that the nitrogen gave an increase of 16 per cent, potassium 10 per cent, and phosphorus 46 per cent, a total of 72 per cent which is very close to the gain resulting from the three together, 70 per cent. However, as the duplication was not very good in any of these cases, it is not wise to adhere too closely to these figures, hut this probably is true; the phosphorus helps the most, the nitrogen next and the potassium the least of three ele- ments. Concerning the different forms of nitrogen, the dried blood and the peptone seem to be as good as the nitrate, but as one of the nitrate pots had a standing of 135, it is not certain that these forms are better than the nitrate. Several other series were run, for it was necessary to thoroughly establish the point that the manure had a beneficial action other than that attributable to the soluble mineral plant food found in it. Summing up these experiments where different samples of soil from this field, and both solid and liquid manure were used, the results show that if the clover on the manured pots is ranked as 100, the mineral fertilizers gave a growth equal to 75 in the first series, 93 in the second, 80 in the third, 80 in the fourth, 72 in the fifth and 61 in the last IOWA ACADEMY OF SCIENCE 117 series. At no time have the minerals given as good growth as the manure, and in the earlier trials the amount of soluble plant food was much in favor of the mineral fertilizers. The pictures show something in addition, and that is, that the manure helped the clover immediately and some time before the minerals helped it. Therfore if the green weight had been taken earlier, the difference would have been greater. With all this evidence it is certain that manure has some constituent that helps the growth of clover, other than the nitrogen, potassium and phosphorus found in it. The question now is, what is this constituent of manure? It has been shown that the manure did not correct acidity of the soil, that the physical effect of the manure is not a help to the clover, and further, that it was not on account of the bacteriological relations. There seems to be only two possible explana- tions left. One is that the soluble organic matter in the manure is used as such directly by the clover plant for nourishment, without first being broken down and then assimilated in simple forms. The second is that there is a poison in the soil and that the manure neutralizes it. The one is the toxin theory, the other the soluble plant food theory. At this time the plant food question will be discussed, leaving the other to be considered by itself. There have been a few investigations that throw some light on the question of the ability of plants to use organic matter as food. L. Lutz has reported considerable work in Bulletin de la Societe Botanique de France. Abstracts of these papers have appeared in the Experiment Station Record from time to time.^ Lutz has found that various nitrogen compounds can be assimilated directly by plants. He has done a vast amount of experimenting, using flowering plants, algae, fungi and molds, and has tested them with a great number of nitrogenous compounds. He uses a sterile medium, sand or similar culture, and for each kind of plant the only source of nitrogen was to be found in the compound under investigation. Experiments are reported with cucurbit seedlings, in solutions containing leucin and tyrosin as the only sources of nitrogen. Where leucin was added to the culture medium, gains of 35.8 per cent to 40.8 per cent in nitrogen are reported, while for tyrosin a gain of 11.9 per cent is given. Leucin being more soluable is much better assimilated than tyrosin. Leucin contains the radicle NH2. It occurs in different animal fluids and is physiologically very important. It is formed by the decay of albuminoids and is soluble in 48 part of water. Tyrosin is quite similar. The results, the author claims, have a practical bearing in the practice of composting. In this way the frequently rapid action of manures may be ex- plained. The author believes it is practically demonstrated that many organic nitrogenous substances are directly assimilated by plants, and the common belief that ammoniacal fermentation takes place first, followed by nitric fer- mentation, is not in accord with what actually occurs in the plant. What about the assimilation of carbohydrates by plants? M. Molliard^ of France experimented with radishes, one lot being grown in mineral solutions, the other in various forms of carbohydrates. When grown in solutions of saccharose, glocuse, levulose, dextrin, etc., the color, size, form and structure of the leaves were greatly modified. The plants were able to make consider- able growth, utilizing the carbohydrates through their roots. ^Exp. Sta. Rec. XVIII, p. 348. This gives previous references. •■^Exp. Sta. Rec. XVIII, pp. 25 and 127. 118 IOWA ACADEMY OP SCIENCE Geo. F. Atkinson^ in the bulletin, “The influence of mushrooms on the growth of some plants,” gives a valuable contribution to the question of the ability of plants to use soluble organic matter directly as food. The author first proves that mushrooms are available for food for several green plants, both when fermented and when unfermented. These were not tested under sterile conditiqns and the unfermented had a chance to ferment, and therefore it is not certain that the organic compounds were used unchanged. He next grew radish and cabbage in pure cultures with agar as a substratum, and he found that both the fermented and the unfermented mushroom material caused some growth of the plants, although not quite so much as that caused by the nutrient solution. We quote: “These pure cultures show that for the radish and cabbage there is plant food for autotrophs in an unfermented in- fusion of the common mushrooms, for they grew to a larger size here than in distilled water. The unfermented mushroom, however, does not offer so good a nutrient as the products of fermentation do, and this is not surprising, although it is a little surprising that the unfermented mushroom can serve as a nutrient for autotropic green plants. Mendel has shown, however, that a considerable part of the nitrogen in mushrooms probably exists as non-proteid nitrogen, some in the form of cellulose nitrogen and some in a form that can be extracted with alcohol. The former probably becomes available in the fer- mented mushroom, while the latter is directly available in the infusion of the unfermented mushrooms.” The author thinks the evidence conclusive that the plants used the nitrogen directly as it was found in the mushrooms without its being changed into the nitrate or ammonia form. This is undoubtedly true if it is certain that the only way organic compounds of nitrogen can be con- verted into the ammonia or nitrate form is through the action of bacteria. This point has been considered settled by bacteriologists. The only other ex- planation is that the organic substances were changed by the direct oxidizing action of 'the roots of the plants themselves. There is very little evidence to support this view, however, and it seems probable that in this case soluble organic matter was used directly as plant food. One more reference will be given. It is to the article of J. Lefevre^ entitled, “The development of chlorophyllous plants in the absence of carbon dioxid, but with non-toxic quantities of amids.” A series of experiments were con- ducted with cress and sweet basil grown in pots under bell jars without carbon dioxid, but in the presence of a number of amids. The plants were supplied with chemical fertilizers to which was added a mixture of tyrosin, oxamid, glycocoll, alanin, and leucin at the rate of 1.1 g. for every 500 g. of soil. The plants were observed under conditions of light and darkness, and it was found that in the presence of sunlight they were able to make considerable growth, attaining in six weeks a size fully ten times that of the original, and with well developed foliage and flower buds. As this growth took place in the entire absence of carbon dioxid, the carbon required must have come from the amids and was taken up by the roots. That the transfer was not simply osmotic, but true synthesis, is shown by the absence of all, or nearly all, growth when the plants were kept in the dark. Apparently photosynthesis took place in almost normal amount. But if it is admitted that plants can, under certin conditions, use organic substances directly as food, it has not been shown how general the practice is. ^Cornell, N. Y., Exp. Sta. Bull. 240. ^Bxp. Sta. Rec. 19, p. 22. Plate VI. Effect of drying the soil, IOWA ACADEMY OF SCIENCE 119 It by no means proves that the manure nourished the clover in the case under investigation directly by its soluble organic matter. But why should it seem strange that flowering plants should be able to assimilate soluble organic matter as such and use it directly? We are still slaves to Liebig’s mineral theory. Plants undoubtedly can be brought to per- fection on mineral food alone, but this is not saying that they could not use other food. In fact many plants do use organic food. The non-chlorophyl humus plants subsist on organic food, and if they can, why is it not possible for chlorophyl plants to do so? . In fact some of them do. The mistletoe uses elaborated food. The carniverous plants, as the sundew and the pitcher plant, growing on the northern bogs use insects as food. The sundew captures and digests insects on its leaves and these help it to grow better and produce more and better seeds. The pitcher plant also is helped by the insects that it en- traps and digests. This investigation of the plant food problem has brought out the following points: it has proved that manure has a beneflcial action other than that attributable to the soluble mineral plant food found in it, and this beneflcial principle is not lost by boiling the liquid manure. It has been shown by scien- tiflc investigators that plants under certain conditions can directly , assimilate many soluble nitrogen compounds, and also certain carbohydrates. The evidence is far from being conclusive that in the case of the clover in question the soluble organic compounds of the manure were used directly as food. It is not proved, but enough evidence has been submitted to keep the question open. THE ANTITOXIC ACTION OF THE MANURE. The Bureau of Soils has advanced a theory in regard to the cause of unpro- ductive or worn-out soils, which is well stated in the following extract.® “Infer- tility is often due to the presence of toxic organic bodies in the soil, either excreted by the previous crops or perhaps formed by the action of bacteria, molds, or ferments from the plant remains. These toxic bodies are organic. They may be fatty bodies, nitrogenous bodies, or non-nitrogenous. They appear to be quite unstable in the soil, changing rather easily by oxidation into harm- less or even into beneflcial bodies. They are not equally harmful to all plants.” There were many things in connection with this investigation that suggested a toxin in the soil as the cause of the poor growth of the clover, and for this reason the toxin theory was given as thorough an investigation as the circum- stances permitted. One of the occurrences that supported the theory was the fact that the soil when kept in the greenhouse gradually changed in its atti- tude towards the growth of clover. As evidence of this, the following pictures are submitted: Pots 44 and 39 were planted soon after the soil came to the greenhouse and the pictures were taken sixty-five days after the series was planted. Pot 71 was filled from the same sample of soil that had been kept in the greenhouse and allowed to dry for nearly three months. The picture was taken sixty-nine days after planting, therefore it is only four days older than pot 44, but there is a remarkable difference in the growth. A change has undoubtedly taken place in the soil and the most probable explanation is that some harmful sub- stance that was hindering the growth of the clover in the first place, has dis- ^Bulletin 55, Bureau of Soils, p. 64. 120 IOWA ACADEMY OF SCIENCE appeared and has allowed the clover to grov/ in a normal manner. The only- other explanation is that the plant food has become more available, but this is easily disproved. Pot 39 received soluble plant food in abundance, undoubtedly having a great deal more than pot 71 could have, taut pot 39 is only a shade better than pot 44 and not nearly up to pot 71. Therefore it is not a plant food question. This was not an isolated case, but the same occurrence hap- pened several times. The soil, when allowed to lie in the greenhouse and dry for several months, invariably became much better suited for the growth of clover. This certainly suggests the presence of a toxin in the soil. The methods pursued by the Bureau of Soils to determine the presence of a toxin were not applicable -in this case, for clover does not submit to the special treatment required, namely, growing in w^ater cultures in bottles. An approach to their methods was made by proceeding as follows: Soil sufficient to fill a pot was spread out one inch deep in a large sieve over which a piece of muslin had been spread. Water was leached through this until twice the weight of the soil had run through. The soil was then dried until it came to optimum water content, carefully worked and treated for several days to destroy any lumps, and then packed into the pot. The leached water was applied to the soil for another pot. This was allowed to dry and was then put into optimum physical condition and packed into the pot. It would seem that if this soil contained a soluble poisonous substance that retarded the growth of the clover, that the soil would be better for washing. It would also seem that if this extract containing the toxin were transferred to another sample of this soil, that it v/ould be there concentrated and still further hinder the growth of the clover. Of course, this extract will carry other things beside the toxin, among which is considerable plant food, but if the toxin overbalances the effect of these things in the original soil, why would it not have the same effect when applied to a new pot of soil? In the following series, pot 224 was filled with soil which had been leached, and this leaching, or extract, was added to the soil in pot 222. In the same way the leaching from pot 225 was added to pot 223. The series was planted October 19, 1906, and it was harvested ninety-one days later. The data secured is here given. TOXIN EXTRACT SERIES II Treatment Green weight g No. plants Relative weight Average 200 Check - — 4.1 10 96 201 Check 4.4 10 103 100 222 Extract added 4.0 10 94 223 Extract added 5.9 10 139 116 224 Leached — _ _ 5.45 10 128 225 Leached __ 4.9 10 113 120 The data shows that the pots which were leached have an average gain of 20 per cent, showing benefit from the. process. But the effect of adding the extract to the soil is uncertain. One of the pots shows a slight decrease in the grov/th of the clover, and the other one a large gain. Therefore it cannot be claimed that the presence of a toxin was proved by the experiment, but the results certainly suggest that there was a toxin in the soil. Undoubtedly the method is crude, and it is not certain that reliable results could be obtained by it, no matter how large the number of duplicates. IOWA ACADEMY OP SCIENCE 121 The problem was attacked from another side by using an entirely different medium in which to grow the clover. Quartz sand was used. This was ab- solutely neutral and non-toxic. With it as a substratum, eliminating the factor of the soil, the action of the manure was seen directly, and it was not com- plicated by appearing in connection with the action of the soil. For this experiment a medium grade of quartz sand was used. The sand was prepared by placing it in pots with drainage outlets, digesting it with a 10 per cent solution of sulfuric acid, and washing the acid out with tap water until the sand was neutral in reaction. The tap water was then washed out with distilled water and the sand dried. It was dried in order that the net weight of the sand going into the pots could he known, and the pots be kept at the opti- mum water content. Gallon pots were used with the outlets stopped. 4,700 grams of the dry sand were placed in each pot. One gram of c.p. calcium carbonate was added to the sand in each pot to prevent any possible acidity. Enough distilled water was added to bring the sand to 15 per cent water con- tent, as this seemed to be its optimum. Distilled water was used throughout in Vv^atering the series. By weighing at any time the per cent of water in the sand could be known and water added to supply the evaporation. The nutrient solution used was the standard one used in the laboratories of the Iowa State College. The following comparisons shows the elements of fertility found in it and in the sample of manure leachings with which it is compared. Element's Nutrient solution, g. per L Manure leachings, g. per L N 11.2 .470 P 2. .093 K 2. 1.080 Five c. c. of the nutrient solution was used per pot on those treated with mine^’ai plant food. 117.5 c. c. of the manure leachings were applied to each pot treated with manure. This amount of leachings contained the same amount of N and P as 5 c. c. of the nutrient solution, but considerably more K. The series was planted July 25, 1907, and the clover sprouted uniformly and grew off without any check. The treatment of the series is shown in the following table which also gives the notes taken on September 6th, and the final weights and notes made Oc- tober 10th. SAND SERIES, PLANTED JULY 25, 1907. 1 Treatment Notes Sept, 6 Weights ahd notes Oct, 10 No. of plants Height inches No. of plants Height inches Weight of tops g Weight of roots g Root nodules 507 Check 9 .87 7 1. .2 .14 None 508 Check 10 .75 7 .75 .2 .12 None 500 Check 10 1.00 10 1.25 .5 .17 None 510 Manured __ 10 1.25 3 .75 .1 .10 Few 511 Mfinnrpfl 3 1.12 512 Manured _ __ 9' 1.75 5 2. .7 .20 Few 513 ISTnt Sol 8 1.25 514 Nut. Sol 10 5.00 10 8.00 15.2 3.10 Abundant 515 Nut. Sol 10 5.00 10 7.50 15.3 3.40 Abundant 122 IOWA ACADEMY OF SCIENCE All the plants were inoculated with the clover bacteria on August 6th. On August 10th all the pots had a stand of from fifteen to twenty plants, and they were thinned down to ten plants per pot. The plants in all the pots were healthy and on a par. By August 23d, pot 513 began to look unthrifty. The leaves lacked chloro- phyl and the plants soon began to drop behind the others, and in another month they were all dead. There was considerable growth of algse over the surface of the sand, tinder the microscope this was seen to be an unicellular plant gathered together in clusters. The species was not determined. This pot was very evidently diseased, and it is taken out of the reckoning. By August 23d the manured pots began to drop behind the pots treated with the nutrient solution, and they were given the second application of 117.5 c. c. of manure leachings to each pot. 5 c, c. of the nutrient solution, diluted to 117.5 c. c. were also given at this time to the pots that had received this treat- ment at the beginning. Three days later it was seen that several of the plants in the pots treated with manure leachings were suffering from the application last given. They were watered to dilute the toxin as much as possible. By September 18th all the plants on pot 511 were dead. Over half the plants on the other manured pots also died before the end of the experiment. It is seen by studying the data given above that the clover in all the pots started off together and grew well, showing that the sand was a good medium in which to grow the clover. This also disposes of the question of any ill effects arising from the toxins thrown off by the germinating clover. Any such toxin was in such minute quantities that it did not affect the growth of the clover. The check pots show this. The clover on these pots made a normal growth for the first four weeks, after which it grew but little, but most of it lived until the end of the experiment, which ran eleven weeks. The manured clover at the end of six weeks showed only a slight gain over the checks. This gain showed that the manure did furnish some plant food to the clover, but it was very little. The manure was evidently poisoning the clover, for one-fourth of the plants were dead at this time, and three-fourths of them were dead at the end of the experiment. Considering the condition of the clover at the close of the experiment, it is seen that only a few of the manured plants received any benefit from the manure, and they only to a slight extent. In striking contrast to the behavior of the manured plants, were the plants fed by the nutrient solution. These grew without any check, in a normal manner, showing perfect nourishment, leaving out of consideration the dis- eased pot. At the end of six weeks they were four times as big as the manured plants, and at the end of the experiment the weight of the tops per plant was over ten times that of the manured plants, and the weight of the roots eight times as much. In brief, the nutrient solution was a good plant food under these conditions, and the manure by itself was not. It might be thought as an explanation of its lack of feeding power for the clover, that the proper bacteriological changes did not take place in the manure extract because the sand differed so from the soil. There are two answers to this: In the first place the sand was not kept sterile, but was at all times open to inoculation from the air and the dust of the room. The sand was also inoculated with a soil extract as noted, and it had every chance to become filled with soil bacteria. In the second place, the IOWA ACADEMY OF SCIENCE 123 work on the bacteriological relations of the manure, elsewhere reported, reached this conclusion. “Bacteria are in no way responsible for the beneficial action of the manure on the growth of the clover, for in the first place it was shown that sterile manure was as beneficial as the unsterilized, and in the second place it was shown that when the whole pot was sterilized the crop did not suffer, but was even a little better.” Therefore it was not on account of the bacteri- ological relations that the manure did not nourish the clover when grown in the sand. The following points are proven: 500 c. c. of manure leachings when applied to a pot of the soil under study, caused a remarkable growth of the clover dur- ing the first two months of its life. The nutrient solution when applied to this soil helped the clover finally, but the help was very tardy in coming. 235 c. c. of the manure extract (in two portions) when applied ro the same sized pot containing an equal number of clover plants, but filled with the quartz sand, failed to feed the clover, but on the contrary poisoned it. The nutrient solu- tion in this same sand caused a perfect normal growth. The problem of the action of the manure on the soil has been narrowed down to the plant food or the antitoxic action of the manure. By taking the manure and the clover away from the soil and placing them in this neutral sand, it is easy to see how the manure affects the clover. If the manure fed the clover in the soil it should do the same in the sand. If the soluble organic matter in the manure was used directly by the clover and was better suited to it than mineral food, then the plants fed by the manure should have surpassed the plants fed by the mineral food when they were both grown in the sand. The failure to do so proves that the clover does not use the soluble organic matter as food, and the remarkable growth of the clover treated with manure when grown in the soil is not due to the plant food found in the manure. Looking at the question from the side of the soil, the theory that the soil experimented with was a poor medium for the growth of clover simply for the lack of readily available plant food, and that the manure supplied this, is untrue. The sand experiment showed that the nutrient solution was a good plant food, but when this was applied to the soil the help it gave the clover plant v/as very tardy. On the other hand the manure is shown not to be a good plant food by itself, but when applied to the soil the benefit received from it was immediate and striking. The only explanation left for the action of the manure on the soil, is the toxin theory. There were toxins in the soil which were neutralized by the manure and this purified the soil, making it a good medium for the growth of clover. When the clover was grown in the sand, no toxins being present to neutralize, the antitoxin in the manure w^as an injury to the clover. The soil pots that were treated with mineral fertilizers apparently had the toxins cor- rected by the combined action of the clover roots and the chemicals, but this was a slower process than the action of the manure. That this action can take place has been demonstrated by the work of the Bureau of Soils.^ THE TOXIC ACTION OF COCKLEBUES. The previous study has shown that there is a toxin in the soil which is being investigated. This toxin may have arisen from various sources and it is possible that it may have come from some of the weeds which grew in the ^Bull. 47, Beureau of Soils, U. S. Dept. Agri. 124 IOWA ACADEMY OP SCIENCE field. In considering the matter, suspicion fell at once on the cocklehurs, xanthium canadense. The experiment field was very foul with this pest when the station secured it, and it was noticed that the soil secured the first year showed more toxic effect than that secured the second year, either in the greenhouse or in the field. This might have been due to the clean culture given the field as soon as it came under the management of the station. Henry Wallace^ reports that the idea of the toxic action of weeds came to him in a conversation with the celebrated Sir John B. Lawes. When looking over his famous experimental plots at Rothamstead, England, he showed Mr. Wallace a field of wheat that had been in continuous cultivation without ma- nuring for forty-five years, with a gradual decreasing yield. It had, however, been carefully hand weeded; and Sir John made this remark: “We must get rid of weeds. Weeds poison the land.” That the bur is poisonous to animals is known. Mayo® states that the com- mon cocklebur seems to cause poison only in its early two-leaf stage, when the cotyledons are well developed. Animals never eat the unsprouted burs for very evident reasons. He mentions cases where it seems that the burs had killed quite a number of hogs. Nobody has isolated and studied this poison. The poisonous principle of another species of cocklebur, X. strumarium, was investigated by A. Zander^, a German investigator, in 1881. He isolated the poisonous principle and named it zanthostrumarin. No formula or classifica- tion v/as given for the poison. If the cocklebur contains a substance that is poisonous to animals, why should not this substance he poisonous to plants? The living cells of animals and plants are very similar and respond to stimuli in nearly the same manner. They are affected by the same poisons and differ only in degree of susceptibility. With a view of investigating the production of a toxin in the soil by cockle- burs, five samples of soil were secured from the field in October, 1906, so that soil which had suffered different treatments could be compared. These samples were pulverized as soon as they reached the laboratory and placed in closed cans to prevent drying, in order to keep them as near field condition as pos- sible. A sample was taken from plot 101 to be as near as possible like the samples secured the previous year. This w^as in clover at the time the sample was secured, and had been in oats and clover the year previous. The clover was a thin stand. Samples were secured from plots 113 and 213. These were new plots added in the spring of 1906. Plot 113 was sown to cowpeas in June but they had proved a failure. Plot 213 was in oats and clover. The oats yielded 7.5 bushels per acre and the clover was a failure. They both raised a very light crop of beans the previous year, w^ere left rough and lumpy, and were very foul with cocklehurs and horse nettles. A sample was secured from plot 208. This had the same crop and treatment during 1906 as 213, but the oats yielded 23.1 bushels. The clover was practi- cally a failure. The crop in 1905 was corn which had been kept free from weeds. -See Wallaces’ Farmer of June 7, 1907. 3Proc. Am. Vet. Med, Assn., 1902, p. 194, ^Dictionary of the Active Principle of Plants. Solin. IOWA ACADEMY OF SCIENCE 125 A sample was also secured from plot 308. This had been in corn both years, was free from weeds and was in good tilth. None of these plots had received any manurial treatment. They were all check plots and differed only in crop and cultural treatments. Cocklehurs were supplied to two of these soils. They were freshly gathered burs, ground and added to the soil at the rate of 19 grams per pot, which is .5 per cent of the weight of the soil in the pot. The percentage of burs which might occur in the soil under field conditions is estimated at .2 per cent. The burs from one medium sized plant were found to weigh 70 grams. This plant occupied about two square feet of space, and at this rate the crop would be 3,361 pounds per acre. When we take into consideration that the leaves and the stalks also fall on the soil, and that there are residues of previous crops, for the burs are very slow in decaying, it is not hard to believe that two tons is a fair estimate for a bur crop. A good crop of corn, including the stalks, is three or four tons per acre. Two tons incorporated in the top six inches of the soil is .2 per cent. Therefore the burs were supplied in the pots approxi- mately twice as heavily as they would be in the field. The 19 grams of burs contained 1.74 per cent of nitrogen, or .36 grams. They contained .4 per cent of phosphorus, or .076 grams. The potassium was not determined, but as in all the previous experiments it has not proved a contribut- ing factor in the growth of clover, the exact amount present was not material. The manure leachings had .2 grams of nitrogen and .0456 grams of phosphorus. Therefore the burs contained nearly twice the amount of plant food that the manure- did. A series of pots from these samples was planted October 19, 1906. Final weights were secured January 18, 1907, or ninety-one days after planting. The series of the different soils v/ith the treatments and the results are given in the following table. OCTOBER BUR SERIES. o ft d Soil plot Treatment Green weight No. plants wt. per plant g Relative weight Average 200' 113 Check 4.1 10 .41 96 201 113 Check __ _ 4.4 10 .44 108 100 202 113 Manure leachings 7.9' 10 .79 186 203 113 Manure leachings 9.5 10 .95 223 205 ■242 113- Cocklehurs .'5% _ _ 4.15 7 .593 140 243 113 Cocklehurs .5% 4.8 & .80 188 164 226 101 Check 6.2 10 .62 146 227 101 Check _ _ 6.15 10 .615 145 145 230 208 Check __ _ 4.4 10 .44 103 231 208 Check 6.0 10 ,60 141 122 234 213 Check 3.0 • 8 .375 90 235 213 Check 4.9 10 .49 113 102 238 213 Cocklehurs .5% ___ 5.35 . 9 .593 140 237 213 Cocklehurs .5% 5.4 10 .54 127 33 238 308 Check _ 4.95 10 .495 116 239 308 Check 5.1 10 .51 120 118 The data given above contains considerable support to the theory that the burs grown the year previous had left a toxin in the soil, and that the burs when added to the soil also poisoned it. The soil from plots 113 and 213 which had run to burs in 1905 and grew practically no crop in 1906, were on a par for clover growing. Taking these as a standard, the soil from plot 101, which 126 IOWA ACADEMY OF SCIENCE had been kept free from burs for two years, was in oats the first year and a thin stand of clover the second year, was 45 per cent better for clover growing. The soil from plot 208, given clean culture, corn the first year and oats the second, was 22 per cent better. The soil from plot 308, given clean culture and in corn both years, was 18 per cent better. The burs in one soil produced a gain of 64 per cent. In this case the stand was light and as the gain was calculated per plant, it gave the burs an advan- tage. In the other soil the gain was 33 per cent. This shows that the burs did nourish the clover, but not to the full extent of the plant food found in them. They had practically twice the plant food that the manure had, but the gain was much smaller than that produced by the manure, which was 105 per cent. Either the plant food in the burs was not available, or the burs con- tained a poison which counteracted much of the plant food action of the material. This pot method is somewhat crude and results obtained from it are not entirely satisfactory. The trouble is partly that results are based on weights of clover several months old. The burs are decidedly toxic to clover at germ- inating time, but after the plant is once started, the bur has a much smaller effect on it. Field observations established the fact that clover and cockleburs may grow side by side, if not in harmony, at least with tolerance-. The effect of the burs on the germinating clover is shown by the following notes: On October 25th it was noted in the series just described that the clover was coming very good and fairly even in all pots except in 236 and 237, which had none sprouted, and in 242 and 243 which had six and five respectively. These pots were the ones treated with cockleburs. Pots 236 and 237 were replanted with ten seeds each. This was six days after the clover was first planted. Five days later, pots 242 and 243 had several plants each which had come through the soil but the cotyledons ware burnt off. Three days later all these pots treated with burs had additional seeds planted in them to supply the lack of stand. In spite of this extra seeding it is seen by the table that only one of the four pots had a full stand. Just about one-fourth of the seeds planted in the pots treated with .5 per cent of burs succeeded in producing clover plants. In the other pots, from 90 per cent to 95 per cent of the seeds produced vigorous plants. The burs undoubtedly hindered the germination of the clover by poisoning it. The nature of the poison in the burs was not ascertained. They were tested for alkaloids but none were found. Work in physiological chemistry during the last two decades has been char- acterized, by a thorough and systematic study of solutions from both the theore- tical and experimental points, of view. The discoveries made in this work have been a great help in giving an insight into some of the problems of plant physiology. A vdde field of research along physiological lines opened up by applying to the field of biology the dissociation theory that has proved so fertile in chemistry and physics. A desire for a deeper and clearer insight into the subject of the nutrition of plants has lead many botanical investigators to study the poisonous or stimulative qualities of a large number of com- pounds. The literature on this subject is very large. These men have devel- oped a method of research, which, although the matter of detail varies con- siderably, in the main features may be briefly described as follows: Seeds of IOWA ACADEMY OP SCIENCE 127 the plant which it is decided to use are germinated, and when the radicles are a few mm. long they are placed in the solution to he tested, and the effect of the solution on the growth and vitality of the radicles is noted. It is not a question of nutrition and no plant food problem can he attacked in this way. The radicle is fed hy the store of plant food in the seed, and any effect which a solution may have is due to injury or, it may he, stimulation. The radicles are extremely sensitive and this makes it a very delicate test. The ordinary distilled water of our laboratories is entirely unfit for use in these investiga- tions and especial precautions are always taken to get non-toxic water. This shows the delicacy of the method. The presence of a toxin in the burs was tested by this method which may be called the Plant Radicle Method. Corn was first used as an indicator. 15 g. of dry burs were ground as fine as possible, placed in a small cloth sack, boiled in distilled water, and the extract thus obtained brought to 100 c. c. This extract contained 1.35 per cent solid matter and is designated in the following tables as ext. N. Diluted to twice this volume it is called N — 2, etc. No mold would grow on this extract, either N strength or N — 2 strength, even when inoculated with mold. This shows that it was toxic to mold. The corn seedlings used were germinated between sheets of filter paper and the moisture supplied by wet sphagnum moss above and below these sheets. Fresh sheets were used each time to avoid mold. Seedlings that developed normally and with straight radicles were used. The test was made in test tubes of various sizes, all the tubes of one series, however, being of a size. A cork was made to fit the tube, the radicle of the seedling was passed through a hole in the cork and into the liquid to be tested, which filled the tube up to the cork. The length of the radicle was marked on the outside of the tube by a blue pencil. The seedlings were allowed to remain in this position for twenty-four hours and the growth if any v-as measured by holding the tube up before the eye and measuring from the blue mark to the end of the radicle. This could be very easily and accurately done. The solution was then emptied, the tube cleaned carefully, filled with distilled water, the seedling rinsed and replaced, and the position of the end of the radicle marked on the glass. In twenty-four hours the growth was again noted. This second day’s growth in distilled water was to determine the condition of the radicle. If no elonga- tion took place it was dead. If it was as long as the check it was uninjured. If the elongation was less than the check it was injured, and the degree of injury could be very accurately judged by noting the amount of retardation. Observations confined to the first day are not conclusive. The best and most practical test for vitality is the ability to grow when taken out of the toxic solution and placed in distilled water. The above method is a slight modifica- tion of that used by Loew and Dandeno, which seems to be the best and most convenient of all the methods given.^ 128 IOWA ACADEMY OP SCIENCE TOXICITY OP COCKLEBURS. July 20, 1907 . 5 c. c. test tubes used. Growth in mm. Ext N Ext N-2 Ext N-4 Check 1 1 1 2 1 2 1 2 1 2 Tst dflv, pxtract 0 0 0 2 11 5 28 40 2d day, distilled water 0 0 0 0 17 20 30 38 August 1, 1907. Ext N-8 Ext N-ie Check 1 2 1 2 1 2 1st day, p-jrtraft 21 18 11 12 58 30 2d day, distilled water 26 20 23 27 52 30 This data shows that the extract of normal and half normal strength was violently poison, and the N — 4 strength quite so. Considerable of the poison- ous effect still remained even when diluted to 1-16 of its original strength. As this would bring it down to .08 per cent solid matter in the extract it could not be a question of osmosis or even of the toxicity of nutritive salts in the extract. The toxicity of the burs for clover was also tested by using the following modification: Clover seed was sprouted in a large watch glass in tap water which was changed once a day. When they were well sprouted, seeds were chosen with radicles 5 mm. long and these were transferred to 5 c. c. of the solution to be tested, which was placed in a watch glass and the whole covered with an evaporating dish to prevent evaporation. The length of the radicles was recorded at intervals in mm. The results Were as follows: TOXiCITY OP OOCKLEBIUEc? FOR CCOVER. Ext N-4 Ext N-8 Ext N- -16 Check July 31. 1 2 3 1 2 3 1 2 3 1 3 4 5 6 Length at start 5 5 6 5 5 5 5 5 5 5 5 5 5 5 5 Length August 2 14 11 9 20 34 12 10 12 9 14 15 14 19 19 13 Length August 5 25 15 36 20 18 40 22 * 28 23 21 17 25 25 ip. A. Loew. The toxic effect of H and OH ions on seedlings of Indian corn. Science II 18, pp. 304-308, 1903. Dandeno. Relation of mass action to toxicity. Am. .lour. Sci. IV, 17, p. 437, 1904. *Dead. tAlive. IOWA ACADEMY OF SCIENCE 129 The first trial shows that the bur extract was poisonous to clover, even the one-fourth strength entirely killing the clover. In the second trial the results are somewhat erratic. The N — 4 strength killed only one of the plants, and the N— -8 and N — 16 dilutions were actually stimulating to two of the plants. Still even in the weakest dilution one of the plants was killed, showing toxicity. The clover is not quite as susceptible to the toxin in the burs as the corn. From the trials with the com and the clover the general conclusion can be drawn that there is a substance in the cocklebur which can be extracted with hot water, which is poisonous to them both. Calculations show that the ex- tract from 15-16 of a bur was found in each 5 c. c. of the N — 4 extract, and that 9 per cent of the bur had been extracted. Therefore there was enough poison in one bur to seriously poison the corn or clover radicle in one day. Work had to stop at this point, but the following facts were proven: There is a toxin in the burs, and a sure, easy, and delicate method was found for detecting this toxin. This toxin is not only poisonous to corn and clover when the radicles of these plants is immersed in a water solution of the toxin, but it is also poisonous to germinating clover when growing in the soil. The pot cultures also give strong indications that the presence of the burs in the soil is detrimental to the growing clover. SUMMAEY. The Southern Iowa loess from a certain field was studied in the laboratory to ascertain the reason that stable manure caused the remarkable increase in productiveness which it did when applied to the soil. It was found that the soil was not acid. The physical effect of the manure on the soil was not responsible for the better growth of the crop. Bacteria were in no way responsible for t|ie beneficial action of the manure on the growth of the crop. The investigation of the plant food brought by the manure proved that the manure had a beneficial action other than that attributable to the soluble mineral plant food found in it. Evidence was brought to support the theory that the clover used the soluble organic matter directly as food, but this point was not proven. The study of the antitoxic action of the manure showed that this was the only explanation for the action of the manure on the soil. There was a toxin in the soil which was neutralized by the manure. The soil pots treated with mineral fertilizers had the toxin corrected by the combined action of the clover roots and the chemicals, but this was a slower process than the action of the manure. A study of the cockleburs which grew abundantly on this field, showed that there was a toxin in the burs which was fatal to both corn and clover. The inference is natural that the burs caused the toxicity of the soil. 9 130 IOWA ACADEMY OF SCIENCE BIBLIOGRAPHY OF THE MOST IMPORTANT REFERENCES. Agricultural Bacteriology. Conn. Agriculture. Storer. Alkaloids, Effect of, on the germination and development of seeds. Ex. S'ta. Rec. 6, p. 903. Book of Rothamstead Experiments. Hall. Braezeale, J. F. Effect of certain solids upon the growth of seedlings in water culture. Bot. Gaz. 41, pp. 54-63. Bureau of Plant Industry. Bull. 1. Bureau of Soils. Bulls. 28, 35, 36, 40, 47. Circ. 18. Cameron, F. K. Application of the Theory of Solution to the Study of Soils. Rept. 64, U. S. Dept. Agri. Chester, F. D. Del. Ex. Sta., Bull. 66. Clover sickness. Yearbook, U. S. Dept. Agri.,. 1897, p. 493. Commercial Organic Analysis. Allen. Cornell, N. Y., Ex, Sta. Bull. 240. Geo. F. Atkinson. Curtis, C. C. Turgidity in mycelia. Bull. Torr. Bot. Club, 27. 1. Dandeno. Relation of Mass Action to Toxicity. Am. Jour. Sci., 17, p. 437. Dictionary of the active principles of Plants. Sohn. Experiment Station Record. 2, p. 317. 5, p. 3. 6, p. 284. 15, p. 20. 16, p. 851. 18, p. 25, 127, 348, 542. 19, p. 22. Farmers’ Bulletins, 192, 214, 245. Fischer. The Structure and Functions of Bacteria. Halstead, B. D. N. J. Ex. Sta. Bull. 135. Heald, F. D. On the Toxic Effect of Dilute Solutions of. Acids and Salts upon Plants. Bot. Gaz. 22, p. 125. Humus on Poisons in Soils.' Effect of. Ex Sta. Rec. 16, p. 228. Illinois Ex. Sta. Bull. 93, 99. Circ. 68, 96. Iowa Ex. Sta. Bull. 82, 98. Jensen, G. H. Toxic Limit and Stimulation Effect of some Salts and Poisons on Wheat. Bot. Gaz. 43, Jan., 1907. Kahlenburg and True. On the Toxic Action of Dissolved Salts. Bot. Gaz. 22, p. 81. Kearney and Cameron. Report 71, U. S. Dept., Agri. Livingston, B. E. The Role of Diffusion and Osmotic Pressure in Plants. The University of Chicago Press.- 1903. Loew, F. A. The Toxic Effect of H and OH ions on seedlings of Indian Corn. Science H 18, p. 304. 1903. Loew, J. The Physiological Role of Mineral Nutrients. Bull. 18, Div. Veg. Phys. and Path. U. S. Dept. Agri. Manures and Manuring. Aikman. Mayo, N. S. Proc. Am. Vet. Med. Assn., 1902, p. 194. Physics of Agriculture. King.. Plant Physiology. Peirce. Soils. Hilgard. True, R. H. The Toxic Action of a Series of Acids and their Sodium Salts on Lupinus Albus. Am. Jour. Sci. IV, 9, p. 183. True, R. H. The Physiological Action of Certain Plasmolyzing Agents. Bot. Gaz. 26, 1898. Wallaces’ Farmer. What Barnyard Manure does for the Soil. Oct. 12, 1906. Toxin. Editorial. Feb. 8, 1907. Velvet Weed and Cockleburs. June 7, 1907. Wisconsin Ex. Sta. An. Rept. 1893. IOWA ACADEMY OF SCIENCE 131 THE OKOBOJI LAKESIDE LABORATORY. BY THOMAS H. MACBEIDE. The establishment of the Okoboji Lakeside Laboratory, founded by the alumni of the State University of Iowa, promises to affect so deeply the future scientific work of our state that some account of its beginning and especially its raison d'etre may rightly claim the attention of the Academy. The labora- tory has been located on the west shore of Lake Okoboji in Dickinson county for the reasons following: In the first place the topography of Dickinson county is peculiar, unique. Situated on the western border of the Iowa Wisconsin drift, the region illus- trates, as possibly no other equal area in the state, the special characteristics, not only of glacial moraines in general, but in particular the very expression of the Wisconsin moraine. In fact, I think that it must be admitted that the Okoboji lakes and their encompassing hills do indeed form the finest bit of morainic topography to be found on our western prairie.* This fact, of course, makes the locality an especially interesting field for illustrating to the student all the fascinating features of the latest page in the geologic history of our state. Indeed, the » very fact that the locality is marginal makes it especially interesting, and studies of contact, of movement and retreat, as well as of direction and relation to pre-existing topography — all these things are especially accessible and patent within half a day’s drive along any highway south or west. Secondly, the region having Okoboji for its center is, by reason of the peculiar topography just mentioned, the field of a special fioral display difficult to illustrate anywhere else within such narrow limits. We have a forest fiora and a prairie flora; and neither in this part of the world has ever been ade- quately studied. It is believed that the fungal flora of the region, for instance, is especially rich and interesting. We have all kinds of habitat conditions, from aquatic to xerophytic. We have deep water, shallow water, but perma- nent; marshes, springs; and zerophytic slopes and hill-tops, some so dry as to offer home to the vegetation of the higher western semi-arid plains. The plankton of the lakes is filled with desmids and diatoms and all manner of algal flora, during July and August rich beyond comparison in all that makes up the tide of life for these simple but fascinating forms. Neither have the xerophytes been studied nor the flora which joins these, perchance, in ecologic bonds with their aquatic congeners, for the waters are filled with flowering plants, richly indeed as with floating cryptogams, and the factors of ecology and distribution all are here, in large part so far, unex- plored and certain to interest for centuries generation after generation of Iowa students. *It is here assumed that the Okoboji hills are morainic : further exploration may offer another explanation. 132 IOWA ACADEMY OP SCIENCE For similar reasons, the fauna of the* lake district will reward our constant study. The varied flora, just described, insures a varied fauna. The waters teem with animal life. Probably the protozoa of the whole valley will be found hiding on the vegetation of these quite lakes and pools. Of course, the avian and vertebrate aquatic fauna are rich, and even the terrestrial verte- brates are likely to prove more than commonly worthy of investigation. While this is writing the papers tell of a mountain lion shot in one of the near-by marshy lakes! It is not believed that carnivores of size are likely to abound, not to such extent at least as to warrant a future visit from our nimrodic ex- president, but it is believed that natural science, in all its branches, entomology, ostracology, ornithology, will he greatly enriched by using such opportunity for research as Okoboji may afford. Again, Okoboji as the world knows is already a place of resort, thousands of people And summer . habitation on its shores. So that we find here un- equalled opportunity for bringing scientific work to the attention of people of every class and kind, and confessedly natural history work in all our schools, colleges and universities is too formal, too artificial, too much based upon material specially prepared, laid up in herbaria, or conserved in cases and bottles; the lakeside laboratory offers an opportunity to correct this, at least in some small measure. Ever since the immortal Agassiz stood bareheaded with that famous company on the rocks of Pennikese, the naturalists of the world, at least, have realized that the proper and reverent place for the study of natural objects is in their natural surroundings. Dry dead fungi are dusty labelled things, as meaningless as the stuffed skin of mammal or bird, or a fossil in a box; better than no exhibit at all, to be sure, hut poor indeed as compared with the natural world, where the fungus starts in the forest shade, the wings of bird or insect fan the sunny air, or the fossil speaks its signifi- cance from the stony pages of the riven quarry stone. The lakeside laboratory shall afford to all interested, for once at least a chance to see the real world, nature alive, accomplishing her miracles in their own silent splendor, often needing not, for the student’s appreciation, the voice of interpreter or teacher. A few words now may describe the provisions making for natural history work. The university alumni have purchased property for a plant. About five acres of ground with a cottage for administration purposes, a boat-house, pier, and so forth, are already the equipment. It is expected within the next few days to erect a building for laboratory uses. This building will offer office, library and laboratory for each professor in charge of a line of work. A large hall to seat 125 people comfortably will he accessible for general lectures, evening entertainments, and so forth, and from the university such apparatus will be supplied as to enable ordinary classes to work successfully in botany, geology and zoology. Boats and dredges also will be at hand, while public conveyances enable students to reach conveniently more distant points of interest. It is proposed to offer tents and cottages to all comers up to the limits of laboratory accommodations; at present a class of not more than thirty is in. contemplation; and simple meals will be obtainable at reasonable rates. The classes sought to be accommodated are; first, all students of nature competent to enjoy the laboratory method of instruction; the laboratory shall be open to anybody capable of using its privileges; second, teachers of biologic subjects in academies and high schools everywhere, who may desire to com- bine recreation with work and who may find in the service of the laboratory IOWA ACADEMY OP SCIENCE 133 occasion to acquaint themselves with Iowa conditions and thus better equip themselves for serving the children of the schools; third, graduate students who may desire to perfect themselves in some line of research preparatory or introductory to an advanced degree. Such students are presumably competent to conduct work for themselves, needing simply a place at table and such suggestions as occasion may develop. In general, however, the laboratories for use are to be open to the world, students enrolling in the order in which application arrives. It is hoped that the open door may be thronged and that the enterprise may not only serve those already engaged in scientific work, but may reach and influence thousands and make real all natural science to the upbuilding and quickening of every school, college or academy within the borders of our state. IOWA ACADEMY OP SCIENCE 135 SOME FEATURES OF IOWA GROUND WATERS, II. BY W. S. HENDRIXSON. About two years ago the writer read before this body a paper, under the above title, giving a general statement of his work on the quality of Iowa, well waters. The accumulating experience of the past two years seems to justify at this time a statement of some additional facts that seem important and which may be of interest to the Iowa Academy of Science. The analytical work on which the author has been engaged is now practi- cally discontinued, not completed since the field seems almost without limit, and at present the results are being put in form for publication. During the course of the work there have been accumulated about four hundred analyses of the waters of wells of importance. These wells are fairly dis- tributed throughout the state, and there are representatives in almost every county in the state. A total of about one thousand analysis and nearly as many descriptions of wells have been at hand to give good opportunity for generalizations on the subject under discussion. It is proposed in this com- munication to confine attention to three topics, the availability of ground water in this state, the present and probable future development of this re- source, and the softening of hard water for industrial uses. Certain physical features of the surface of the state of Iowa which contribute to decrease the importance of its surface waters as compared with other states are almost too obvious to require statement. This is a state of comparatively level surface; that is, the differences of elevations above sea-level are small. Taken in detail its surface is gently undulating. There are no mountains, and scarcely anything worthy of the name hills. Ninety-five per cent of the surface is tillable and nearly the whole of it is under cultivation. There is thus very little wild land or forest area as compared with eastern states, to serve as collecting ground for lakes and rivers of good water. The soil is very deep and generally very fine and porous. Under it are the comparatively porous loess and .the sand and gravel of the drift. . The drift covers nearly the whole state -and is very deep, over most of its surface. Though the state has an annual rainfall of nearly thirty- five inches, these conditions contribute to make the run-off small and the amount of water taken up by the ground very large. Owing to the deep drift covering the rock strata, the scarcity of outcrops and the generally unbroken surface of the land, perennial springs that might feed the streams during dry weather are comparatively rare. Without this source of supply, without forest areas to hold the water back, and with the porous soil to take up nearly the whole of the rainfall of the drier months it follows that many of the small interior rivers of the state contract to insignificance during the dry periods, usually of the summer and early fall. At all times and specially during the dry seasons their waters are subject to pollution by the surface drainage, sewerage of towns and commercial concerns along their courses. Owing to the 136 IOWA ACADEMY OP SCIENCE large percentage of plowed land, the fine soil and clays, their waters are very turbid most of the year. In short, such streams as we who cast the fly find in Michigan and Colorado, with their strong currents of pure, clear water, derived from springs and forest covered sand layers, or from melting snow above the habitations of men, are unknown in Iowa. According to present sanitary standards there is no river in Iowa or on its border whose natural waters may be used the year through as the source of municipal supplies. The situation is likely to become worse rather than better as the population be- comes more dense and the industrial interests expand and multiply. Unless some practicable plan of filtration adapted to the smaller places is devised it seems probable that rivers as the source of such supplies will continue to be of secondary importance. Iowa is a state having few lakes of consequence. The only ones of im- portance form a group near the northern border of the state and well to the west. They are far removed from centers of population, they are fed by small streams, are shallow and they cannot be considered suitable the year around for town supplies. The same physical features that cause insuflB.cient and poor river water also make large reservoirs or artificial lakes of good water prac- tically unobtainable. It is an interesting and important fact that the most of the conditions that contribute to make the rivers of smaller importance are the ones that increase the ground water resources and its easy availability. The level surface, the porous soil and drift, the large percentage of cultivated land increase the percentage of water absorbed. The deep soil and subsoil, the sand and gravel of the drift afford it storage. This filtered and stored water is in most regions easily reached by the bored well or the sand point. In very many areas the sand and gravel layers lie in basins or troughs and in such regions flowing wells are secured. In some regions such water-bearing layers are struck high in the drift, but a very large number of wells go to the rock and derive their water from gravel layers just above it. The level nature of the land may also account for the fact that for the most part Iowa rivers and streams have low velocities of flow and meander through wide level valleys, instead of flowing with high velocity between ranges of hills as in more rugged countries. In such valley-plains of rivers, water supplies can be secured from the so-called “under-flow.” In the southwestern part of the state where there are many such streams this source seems to be the best and the most generally resorted to for town water systems. Good examples are Atlantic, Red Oak, Elliott and Griswold on the Nishabotany. Such waters have the advantage that they contain about the same amount or very little more mineral matter than the waters of the rivers themselves. There remains to be mentioned the unparalleled source of well water in the northeastern part of the state, — the sand-stone layers of the Cambrian and Ordovinchian systems, known as the St. Peter, New Richmond, Jordan and Dresbach. This magniflcent source is too well known to require further men- tion. It may be of interest to note, however, that in at fewest flve of the most favorably located counties this source is untouched, and in several others one flnds only one or two wells to each county. Such are the well water resources of the state. To what extent are they being used or to what extent are the people dependent upon them? That well waters have up to this time held the most important place appears strikingly IOWA ACADEMY OF SCIENCE 137 from a study of the municipal water systems of the state. The following figures are from the Underwriters’ Hand-book of Iowa, in which are given all the towns of the state with their populations and their means of fire protec- tion. The populations are taken from the last census, though the edition of the book is for 1907. In going over the list the following facts appear. There are 324 cities and towns having water systems, including stand-pipes, street mains and fire taps. Towns having systems for fire protection only are not included. Of this num- ber six have as their sources of supply lakes, or natural or artificial ponds; twenty-four have water from rivers, and 294 get their water from wells. It appears further that the urban population in towns having water systems are supplied as follows: Prom lakes and ponds. 21,000 Prom rivers .......... 341,000 Prom wells 534,000 It follows that well water supplies about 60 per cent of the dwellers in such towns But, this is only a part of the truth. The inhabitants of such towns are a comparatively small minority as compared with the whole population of the state. There are many large towns without water systems. The people of these towns and the whole rural population are dependent upon wells of one sort or another. Taking this fact into account it follows that about 84 per cent of the whole population are dependent upon ground water. There is much reason to expect a greater proportionate development in the use of ground water, and water from deeper sources. Though there are many towns of 150 to 300 inhabitants that have water systems, there are also many of 500 to 2,000 people that are yet without such systems. They will be forced to provide such supplies in the near future. The indications are that many towns have installed water systems more or less temporary and to meet the then existing needs, whether this temporary character was intentional or not. There is observable a very general tendency to extend well systems and to put down deeper wells as the towns have grown. It is interesting also to note the tendency to provide unfailing water supplies on the farms. Iowa is getting to be a state of very large live stock interests. Stock must have water, and something better than the shallow well, located very likely in some draw, only a few feet deep and provided it may be with only a hand pump, has become a necessity. The result is that farm wells 100 to 500 and even 1,000 feet In depth are becoming very numerous, and it is very probable that with the in- creasing need of plenty of good water, and also the increasing wealth of farmers in Iowa such farm wells will become very general. In the former paper referred to, mention was made of the corrosion of well casings by hard waters. Several instances are on record where casings or parts of them have been taken out of the wells and found full of holes due to pitting. There is evidence that this is very general in wells having hard waters, and though no very accurate data have been collected the probability Is that ordinary iron tubing in wells having quite hard water will be eaten through in from five to ten years. The following is an interesting example in a well in the southern part of the state and in a particular locality where the upper water is very highly mineralized. The well was drilled in 1904 to 138 IOWA ACADEMY OP SCIENCE a depth of 2,054 feet. The following are four analyses of its water made at intervals of about one year. Date of Analysis. Total Solids. Sept. 18, 1905 Sept. 9, 1906 Nov. 26-, 1907 Sept. 9, 1908. 1,228 1,637 1,930 2,594 The content of mineral matter has steadily increased during the four years, and it seems very likely that this is due to the gradual deterioration of the casing due to corrosion. The want of efficiency and durability in the casings is one of the chief weak points in the deep well as a source of water supply. Not only do casings rust through, but in many instances they do not reach sufficient depths to shut out hard water and to prevent caving of shale. The town of Grinnell has lost one well and the capacity of another in quality and quantity has been’ greatly diminished by the caving of shale at the depth of about 1,700 feet or just above the St. Peter. At the present time well number (4) is being drilled and has reached a depth of 1,850 feet. The plans and contract regarding casing are so unusual, and are likely to be of such importance that a mention of them seems desirable. As is well known cast iron far excels wrought iron in its resistance to the corrosive action of air and water. Of course, the mild steel which has so largely replaced wrought tubing on account of its cheapness is still far inferior to wrought iron in durability. Having had experience with both soft steel and wrought iron tubing the Grinnell authorities contracted for a casing of cast iron in well number (4) to reach to a depth of 1,700 feet. If this experiment succeeds it ought to be of much interest from both, the practical and scientific standpoints. There are few if any deep wells near the center of the state from which the waters above the great sandstone layers are entirely excluded. No one now certainly knows what these sandstones are capable of yielding in this region in either the quality or the quantity of water. In the Grinnell wells as they have hitherto been cased, very considerable quantities of hard water have been received from the limestone layers below the casings at depths from 1,200 to 1,600 feet. If the water supply of the new well should prove abundant and should have a mineral content anywhere near as low as the water from the same strata fifty miles to the northeast, it ought to encourage more deep wells in this region, and even the extension of the region of artesian wells farther to the south and west. In any event the successful putting down of this casing will demonstrate the practicability of cast iron for this purpose, and the opportunity of thus very greatly increasing the durability of the casing and the life of the deep well. Iowa waters from whatever source are notably harder than those from cor- responding sources in the states farther east. The wafers of Lake Michigan and of the great lakes generally contain about 130 parts of solid matter per million; lakes and rivers farther to the east contain smaller amounts, even to less than half as much. On the other hand the softest of Iowa river, lake and well waters contain about twice that amount; that is, about 260 parts per million. There are few well waters of this degree of freedom from mineral matter. Excepting a few wells the great majority vary from 350 to 10,000 IOWA ACADEMY OF SCIENCE 139 parts. On Iowa standards a town witb. a supply of water containing 500 parts of solids per million may consider itself fortunate in this respect; 700 parts may he considered fair, and 1,000 parts or even more, tolerable. For boilers and most industrial purposes none of these could be considered very good. One railroad in the state has classified its waters according to standards as follows: less than 134 parts, of incrusting solids, very good; 200 parts, good; 300 parts, fair; 450 parts, poor; 600 parts, had; over 700 parts, very had. According to this standard and its own analyses of waters along its lines no water can be considered very good; only- eight of its waters are good; thirty- seven are fair, and eighty-eight are poor to very bad. If the 123 waters of this road may be taken as representative and the standard quoted as valid, then about tw'O-thirds of the Iowa waters are poor to very bad for boiler use. The case is really worse. Railroads care little about the sanitary “condition of their boiler waters, and they take them from- rivers, ponds and slough wells by preference because they are softer than the waters from deeper wells such as supply cities. Of city supplies probably far more than two-thirds are really poor to very bad for boilers. That hard waters form boiler scale and are very likely to be corrosive are facts too well known by this body to require discussion; also, that scale de- creases the efficiency of the boiler, and corrosion means early and frequent repair and short life of the boiler. Many means have been devised with the object of avoiding these difficulties. From the standpoint of the chemist there is only one right way, if the water is to be used at all and is not bad beyond possibilities of treatment. Since this method has now been introduced on a very large scale in this state by one of the largest corporations and has proved very successful, at any rate a brief statement for record seems desirable. But first as to palliatives and quack remedies. If one wishes to avoid the difficulties attending the use of a hard water for boilers or other industrial purpose, the most obvious thing to do is to soften it, if this is practicable. There is nothing new in the idea of softening water; the chemistry of it has been known for a long time, but there are new develop- ments in methods and the scale on which it may be carried on, at any rate in this state, where on account of the hardness of the waters it should be a matter of very great industrial importance. In order to make more clear the scientific character and efficiency of the method I have mentioned it may be well to describe briefly two palliative methods as carried out on a small scale. One method is by use of the pre-heater, the source of heat being usually exhaust steam. It is a matter of economy to feed the boiler with heated water, and the heating causes the precipitation and settling out of a considerable portion of the calcium carbonate. Sometimes a boiler compound or an alkali is added to the heater, thus removing a portion of the permanent hardness. The method is good so far as it goes, but the apparatus is usually too small to allow proper settling, it is troublesome to manage and its efficiency is farther restricted by the want of knowledge and care of the individual engineer. Perhaps the most generally used and the worst method is that of using alkalies and so-called “boiler compounds” for the precipitation of the solid matter in the boiler. This makes the sludge where it will do the most harm. It may cause foaming, it necessitates frequent cleaning, it may settle in a com- pact mass when the boiler is out of use and cause overheating of the covered 140 IOWA ACADEMY OF SCIENCE plates and even explosion when the fires are again started. As a rule in practice the nature and amount of the boiler compound bear little relation to the work to be done, the compound of unknown composition being added from time to time without much regard to the mineral content of the water or the amount of water used. The treatment is likely to be only partial, or the com- pound is likely to accumulate and cause trouble. The number of boiler compounds on the market is very large and for them their venders claim almost miraculous properties, and they sell them at ex- orbitant prices. A few days ago there came into my hands a boiler compound used in a Grinnell power plant. So far as could be discovered it contained only sodium hydroxide, about 18 per cent, and a very little coloring matter that may have been due to the action of the strong alkali upon the barrel. It was bought by the barrel at eight cents a pound, or about $42.00 a barrel. It was actually worth, barrel and freight included, about $5.00. The man who bought this compound is one of unusual intelligence and business ability. In fact, the ap- peal of the boiler compound to the trade may be likened in many respects to that of the patent medicine, and mystery seems to be the controlling factor. Now, as a matter of fact there are only a few practically useful chemicals for softening water, and they are all perfectly well known as is also their action. There is no necessarily efficient nostrum applicable in all cases. Any peculiar, secret and patented combination ought to be treated as a fraud, and the engineer who applies to a chemist for advice should be plainly told this fact. The chief substances in water that make boiler scale are calcium and mag- nesium in association usually with carbonic and sulfuric acid ions. The scale consists mainly of calcium and magnesium carbonates, hydroxides and calcium sulfate. The chief agents of corrosion are free carbonic acid, and other acids that may be set free by the hydrolysis of salts at the high temperature of the water. The problem is, therefore, to remove calcium and magnesium (secondarily aluminium and iron), and carbonic acid ions, to leave the water neutral or slightly alkaline, with the introduction of the minimum of soluble material. First of all one must have an accurate mineral analysis of the water to be softened. The volume of the water must be measured and the chemicals must be calculated to meet the given case and the amount used weighed. Though there is no logical procedure applicable to all waters, effectiveness and cheap- ness both considered, it is generally better to use only lime if the calcium and magnesium ions do not exceed in equivalence the carbonic acid ion, HCO®; otherwise a mixture of lime and soda ash serves the purpose best. The abso- lute amounts depend, of course, upon the quantities of substances to be re- moved, and their relative amounts must be varied according to the infinitely varying proportions of the ions, Ca, Mg, HCO® and SOi. Every water must have its own proportions precisely adapted to its mineral content. The chief reactions in such water softening are represented by the following equations: 1. CaCHCOa)^ 4- Ca(OH)2 = 2CaC03 + 2H2O. 2. Mg(HC03)2 2Ca(OH)2 = 2CaC03 MgCOH)^ 4- HaO. 3. MgSOi 4- Ca(OH)2 = MgCOH)^ 4- CaSO^. 4. CaSOi 4- NasCOs = CaCOs 4- CaSO^. Equations (1) and (2) show the removal of calcium and magnesium car- bonates, or “temporary hardness.” When the water contains sulfates of these elements, that is, is “permanently hard,” sodium carbonate is also used, and IOWA ACADEMY OP SCIENCE 141 remoYes calcium sulfate already present or formed as in (3) by the reaction expressed in (4). The chemical scheme that I have outlined is the one that is being used by the railroads of Iowa so far as they have taken up the enterprise. The present situation is indicated by the following points from the correspondence with the chief chemists, or engineers of tests as they are in some cases called. Mr. M. H. Wickhorst of the Burlington road writes that they have installed three large plants which are giving very satisfactory results. Mr. Geo. D. Prentiss of the C., M. & St. P. states that his road has attained excellent results at Sioux City and in another plant across the river in South Dakota. Mr. P. O. Bunnell states that the Rock Island could scarcely maintain its present schedule in some regions without the softening plants, and that their system of soft- ening would probably soon be extended to Iowa. To the Chicago & North-western railroad, however, is due the credit of the widest application of water softening on a large scale. The information at hand comes from Mr. Geo. M, Davidson, engineer of tests for many years, through correspondence and a paper on the North-western softening system, published in the Western Railroad Club. This road has in successful operation forty-one softening plants, of which twenty-two are in Iowa. With three exceptions these plants have a capacity of 240,000 gallons a day. The chemical process has already been essentially described. Only a few of the prominent mechanical features and the results can be given. The apparatus is comparatively simple and is constructed in the shops belonging to the road. The essential vessels, excluding the storage tanks for the hard and for the softened water are, a small tank to hold the mixture of milk of lime and sodium carbonate, the mixing tank provided with stirring blades, and two settling tanks. The hard water receives the softening solution just before it reaches the measuring apparatus, which consists of a two-com- partment tilting box, each compartment holding 100 gallons. The tilting vessel operates two pumps whose cylinders supply the softening solution and the length of the stroke can be regulated to supply the desired volume. The weight of water in the tilting vessel is also the source of power to operate the stirring blades and they are reversed with every change of position. Prom the mixing vessel the water goes to the settling tanks of which there are two, each having a capacity of 77,000 gallons. From them the clear water is pumped to the storage tank for use. The effectiveness of the process may be illustrated by the results attained by three plants, at Council Bluffs, Denison and West Side. The average of the incrusting solids of the untreated waters is 644 parts per million, and of the treated waters seventy-four parts. About four grains per gallon or seventy parts per million of incrusting solids marks the usual efficiency without much regard to the character of the water originally. This amount is regarded as practically harmless. The results of the use of this softened water in railroad engines have been very gratifying. The first effect in boilers that have used hard waters is to cause leakage owing to the loosening of old scale. If the tubes are then re- rolled there is very little farther trouble, and the general results is that boiler repair and time lost by engines in the repair shop are reduced to a small frac- tion of what they were when untreated water was used. 142 IOWA ACADEMY OF SCIENCE The cost of treatment varies greatly with the degree of hardness of the water. Pair boiler waters cost about one cent per 1.000 gallons. Prom this minimum the cost increases to ten cents, with the average about three cents per 1,000 gallons. All waters cannot be made good boiler waters by softening. Very hard waters are likely to contain already some sodium sulfate. To remove calcium sulfate by the method described means necessarily an increase of sodium sulfate. If the total quantity present exceeds about 600 parts per million, the result is foaming in the boiler. Iowa waters are hard and trouble with them in boilers and in other indus- trial uses is well-nigh universal. The trouble will not disappear of itself, but will become more acute as the industries of the state increase. I deem it worth while to call the attention of men of science to this most scientific remedy which has been proved wholly practicable on a large scale. It ought to be as practicable for a large stationary power plant or a manufacturing con- cern as for a railroad. In every town of considerable size there are numerous power plants, often laundries, tanneries and the like, and it would seem reason- able for them to unite in the erection of a softening plant for their common use if the method of solving their difficulties regarding water were made clear. IOWA ACADEMY OP SCIENCE 143 THE ANALYSIS OP SMALTITE WITH SPECIAL REPERENCE TO THE ESTIMATION OP ARSENIC AND COBALT. BY NICHOLAS KNIGHT. A gram of the substance is weighed into a porcelain crucible of 150 c. c. capacity, 50 c. c. of dilute nitric acid are added, and evaporated to dryness on the water hath. The nitric acid is removed with sulphuric acid. This treat- ment changes the lead sulphide that may be present to lead sulphate, which with the silica is removed by filtration. The filtrate is diluted to a volume of 200 c. c. and heated to 60°-70°, while a stream of hydrogen sulphide is run into the liquid for three to six hours. This precipitates arsenic, bismuth and copper, all the other substances remaining in solution. After filtering and washing the precipitate in cold water, it is treated with warm potassium sulphide. This dissolves arsenic sulphides, while bismuth and copper sulphides remain unchanged. The solution of arsenic is evaporated to dryness on the water hath, and if sulphides of arsenic and copper separate from the solution as may happen, these are filtered, and added to the other portion. The arsenical residue is transferred to a 150 c. c. crucible and five to seven grams of solid caustic potash are added. Then a stream of chlorine is run into the crucible for twenty or thirty minutes, or until the contents of the crucible bleach litmus paper. With the crucible covered by a watch glass about 50 c. c. of dilute hydro- chloric acid are added, and then evaporated until crystals appear. The opera- tion is then repeated, using 50 c. c. of concentrated hydrochloric acid. By the use of hot water, the contents of the crucible are transferred to a beaker glass and filtered to- remove the sulphur and silica. The filtrate con- taining the arsenic is diluted quite largely with water and kept at a tempera- ture of 60°-70°, while a stream of hydrogen sulphide is introduced for three to six hours. The arsenic sulphide may he collected in a Gooch crucible or on a tared filter. The reactions: CoAs, -t- 6HNO3 = Co(N03)2 2H3ASO, -1- 4NO. 2H3ASO4 5HoS = AS0S5 8H0O. AS2S5 -1- 3KoS = 2K3ASS4. K3ASS4 + 40KOH 32C1 = 4K2SO, -f 32KC1 -f 2OH2O -F K3ASO4. Pot arsenate. The excess of KOH and Cl becomes 2KOH -1- 2C1 = KCIO 4- KCl -f H2O and 3KC10 = KCIO3 -f 2KC1. Adding dilute HCl, 2HC1 -t- KCIO = KCl -f 2C1 -f HoO, the hypochlorite and also the K2CO3 are decomposed. The K2CO3 is formed by the action of the CO2 of the atmosphere upon the caustic potash. It is also necessary to add Cone., HCl to decompose the KCIO3 as follows: 144 IOWA ACADEMY OF SCIENCE KCIO3 + 6HC1 = KCl + 6C1 + 3H2O. K3ASO4 + 3HC1 = H3ASO4 + 3KC1. 2H3ASO4 + 5H2S = AS2S5 + 8H2O. After the first filtration of the arsenic, the iron is next determined, followed by the estimation of nickel and cobalt as follows: The filtrate from the iron is evaporated to a smaller volume, and both nickel and cobalt are precipitated as hydrates with caustic potash. The hydrates are filtered off, removed with a feather to an evoporating dish, and hydrocyanic acid is added until a reddish tint, not very pronounced, is assumed; then a solution of caustic potash, drop by drop, until all is dissolved save a small flocculent precipitate of cobalt para- cyanide. This is filtered through the same paper from which the precipitates were removed. The filtrate is concentrated to a small volume, and mercuric oxide, sus- pended in water is added until the liquid remains a red color. This is Liebig’s method of precipitating the nickel. It is left about an hour on the water bath, when the nickel is removed by filtration. The Coltalt. The filtrate from which the nickel was removed is evaporated to dryness in a platinum dish. The cobalt paracyanide is now united to this main portion. About 30 c. c. dilute sulphuric acid are added, and after half an hour the same quantity of strong acid. It is evaporated to as small a bulk as possible on the water bath, and cautiously heated with the free flame to remove all sulphuric acid. The residue is treated with a little water and the mercury salt that it usually contains is removed by filtering. The filtrate is once more evaporated to dryness, and again filtered to remove the last traces of mercury. The filtrate on the water bath is precipitated hot with a solution of caustic potash. The well washed precipitate is finally reduced to metallic cobalt with a stream of hydrogen. The reactions: Co(N03)2 4- 2KOH = Co(OH)2 4- 2KNO3 Co(OH)2 4- 2HCN = Co(CN)2 4- 2H2O. KOH and HCN are added until the double salt, potassium Cobalto Cyanide, Co(CN)2, 4KCN is formed. Expressing this double salt in another way we have K4 Co"(CN)e. 2K4 C0(CN)6 4- 0 4- H2O = 2K3Co"'(CN)6 + 2KOH. There is a change of valence from two to three. Adding dilute sulphuric acid there results: K3Co(CN)e 4- 3H2SO4 = 3HKS04 4- H3Co(CN)6. The concentrated sulphuric acid reacts as follows: 2H3Co(CN)e 4- I9H2SO4 = 2C0SO4 4- 12CO 4- 12N 4- I7SO2 4- 22H2O. Heating to dryness changes the HKSO4' — 2HKSO4 = K2S2O7 4- H2O. C0SO4 4- 2KOH = Co(OH)2 4- K2SO4 Co (OH) 2 4- 2H = Co 4- 2H2O. IOWA ACADEMY OP SCIENCE 145 THE FRUIT OP VIBURNUM NUDUM. BY EGBERT H. LOTT AND NICHOLAS KNIGHT. The fruit of Viburnum Nudum was gathered in the swampy portions of the territory around Sylvan Beach, N. Y., on the eastern shore of Oneida Lake, August 27th to September 5, 1907. The territory was formerly the lake bot- tom, at the time when the water was discharged into the Mohawk river. An elevation of the land took place, the lake was projected farther north, and the water now reaches Lake Ontario through the Oneida and Oswego rivers. The soil of the Sylvan Beach territory is almost a pure sand, unadapted to agricul- tural purposes. This species of Viburnum grows on shrubs four to seven feet in height. It is common in swampy regions from the New England states to Florida. The portion gathered August 27th was comparatively green, while on the 4th and 5th of September it had become quite ripe. It was then a beautiful cardinal red, very abundant in the neighborhood of Sylvan Beach, and the most gorgeous object in the early autumn landscape. The dried fruit of the species consists of berries that resemble commercial currants. They differ in that their color is bluish black instead of brownish black, and they are more elongated. The odor of the berries is also similar to that of currants. The taste of the berry passes quickly through . different degrees of sweetness to that of a decided bitterness. The bitter taste is very similar to that of a wild cherry, or to the bark of a peach tree, although not quite so strong. The fruit when burned gives off three distinct odors; first, a sweet odor like that of taffy made from sorghum molasses; secondly, an odor somewhat resembling coffee; and lastly, the odor of burning damp straw or leaves, which is very penetrating. The fruits are very easily crushed in an agate mortar. There were 270 grams available for the analysis. The average weight of each was 0.05 gram. THE SUGARS. About 100 grams of the fruit were taken for the sugar extraction. They were placed in a 500 c. c. flask, fitted with an inverted condenser, and treated with successive portions of alcohol for about thirty-five days. The alcoholic extraction was removed each day, and a fresh portion applied. The alcohol was distilled off, and two substances remained behind; one a dark, thick syrup; the other a resinous, gummy substance possessing a bluish clay color. The alco- holic extraction gave an acid reaction to litmus paper. The color and odor of the first extraction bore a strong resemblance to new cider. In a short time the odor resembled old cider, and a test for acetic acid showed that fermenta- tion was taking place. A test with Pehling’s solution at the end of thirty-five days showed that the sugars were almost extracted, and distilled water was substituted for alcohol. The berries under the alcohol treatment remained hard, but on the addition of 10 146 IOWA ACADEMY OP SCIENCE water became soft and mushy. The alcoholic extraction at the end of thirty- five days was almost colorless, while the water extraction was very black, resembling coffee that had been boiled. Ten days more were required to remove all coloration and the remainder of the sugars by the water treatment. The percentage of the sugars was determined by Fehling’s solution of such a strength that 10 c. c. corresponded to 0.05 gram sugar. The determination was made by taking 1 c. c. of the sugar extraction and diluting with 50 c. c. of distilled water in a small beaker. This was heated to boiling and titrated with Fehling’s solution. To ascertain when the end point was reached, a small portion of the solution was filtered from time to time, always pouring the filtrate back, until the sugars had no more reducing power. The filtrate was of a marked straw color until the reduction was complete, at which time it became a light blue. The change in color could be brought about in either direction by three drops of the sugar solution or the same of Fehling’s solu- tion, and so it seemed a satisfactory test. There were found to be 42.85 grams of sugar corresponding to 42.85 per cent. The loss by fermentation was not ascertained. The two different sugar extractions were evaporated to dryness, and the odor was that of scorched sorghum. The residue was a black thick jelly-like substance and had the bitter taste of the original berry. A portion of this residue was purified by heating for several hours on the water bath with purified bone black. The solution w^as quite light in color, and was evaporated to dryness for treatment with phenylhydrazine.. With portions of 0.01 gram sugar, 0.04 gram phenylhydrazine, and 0.03 gram sodium acetate, the test pointed to fructose. Another test with cobalt nitrate indicated dextrose, so it is quite likely both are present. The osazone crystals were purified by crystallizing .with alcohol, and attempts were made to obtain the melting point, but the efforts were unsatisfactory. The residue of the fruits after the sugar extraction was dried and weighed. The loss of weight was 53 per cent. The berries were black in color, shriveled and hard. As a larger quantity of residue was needed for oil extraction, it seemed likely that the sugars might be removed more rapidly by using a litre fiask and larger quantities and changing the solvent twice daily. In two weeks all the sugar in 125 grams of fruit was extracted. This portion was dried and weighed, showing a loss of 48 per cent as compared with 53 per cent the first time. THE ASH. Four different portions of the berries of about two grams each were ashed in a platinum evaporating dish of 100 c. c. capacity. From the first portion silica, iron, aluminum, calcium and magnesium were determined; from the second portion, the sodium and potassium by a modification of the J. Lawrence Smith method; from the third portion, the sulphates,, and lastly, the phos- phates. The analysis showed more sodium than potassium, and the flame test both from the original berry and the sugar syrup pointed in the same direction. The results of the analysis were as follows: IOWA ACADEMY OF SCIENCE 147 FIRST PORTION. SiO. ALO3 Fe.Oa CaO MgO Weight of berries taken Weight of the ash SECOND PORTION. ,2.11 per cent of the ash 3.88 per cent of the ash 3.88 per cent of the ash 7.60 per cent of the ash 1.87 per cent of the ash 2.015 grams 09 grams KoO Na^O Weight of berries Weight of ash... 12.87 per cent of ash 16.79 per cent of ash 2.0403 0.0933 THIRD PORTION. SO3 27.13 per cent of ash Weight of berries 2.0533 Weight of ash 0.0921 FOURTH PORTION. The phosphate was determined by dissolving the ash in nitric acid, filtering and treating the filtrate v/ith a solution of ammonium molybdate. PoOg 12.89 per cent of the ash Weight of berries 2.0523 grams Weight of ash 0.0734 grams The total is 89.09 per cent of the ash; the remainder is organic matter that escaped combustion, and carbon dioxide. A portion of the pulp of the berries after the sugar and oil extractions was thoroughly dried, and 2.6083 grams ashed. The ash weighed 0.0483 grams, about half the weight of the ash of the original fruit, and a much larger bulk of fruit was required to weigh two grams than of the original fruits. The pulp now had only two characteristic odors, that of coffee, and of damp burning leaves. The odor of taffy seemed to have disappeared. THE OILS. The dried berries from the sugar extraction weighing 112 grams, were finely ground in a small coffee mill, and used for the oil extraction. The powder was placed in a 500 c. c. fiask which was tightly fitted with an inverted condenser, and treated with ether. Two weeks were required to extract all the oil. The ether was removed from the oil by distillation. The oil at first was of a beauti- ful green color, due no doubt to chlorophyll. The attempt was made to remove the chlorophyll by filtering through bone black, with ether, in the cold, but no effect wl/atever could be detected. The oil was then heated for twelve hours with ether and bone black, using an inverted condenser, and then filtered The oil now came out a beautiful amber color, the specific gravity of which was 0.9353. It was not possible to solidify it in a freezing mixture. The boiling point is about 82°. It has a characteristic odor which somewhat resembles 148 IOWA ACADEMY OP SCIENCE that of olive oil. Four saponifications were made by Koetstorfer’s method which resulted as follows: Amount Taken Time Heated Saponiflcat’n Equivalent 1 0.857 2 612 2 0.858 4 343 ^ 2'. 302’ 12 291 4 . 3.1605 303 The results indicate that the oil is difficult to saponify, and that complete saponification takes place only after continued heating. The figures show that the oil is one of the oleins in the same group as castor oil, almond oil and olive oil. The conclusion accords well with the physical characteristics. The products of the third saponification were separated. The soapy solution after saponification was diluted with distilled water, and a quantity of ether was added which dissolved the unsaponifiable portion. This was separated from the liquid, evaporated to constant weight and found to be 0.0483 grams. This residue was dissolved in hot alcohol and filtered, and left to evaporate spontaneously. A few minute crystals separated out which were supposed to be chloresterol. After separating the ethereal layer, the remaining liquid was acidified with sulphuric acid and slightly heated, whereupon the fatty acids liberated by saponification collected upon the top of the liquid. These were separated and boiled with distilled water for several hours. They were afterwards separated from the water, dried on the water bath, and found to weigh 3.6033 grams more than the amount of oil at first taken. The increase of weight is due, doubtless, to the oxidation of the acids. Two distinct acids appeared, one very clear and odorless, which crystallized in a freezing mixture to fine needles, and melted at about 4°, the other was a yellow limpid liquid with an odor resem- bling lard. This last crystallized at a low temperature, but we did not succeed in finding the melting point. Judging from the descriptions given in the literature, the clear acid seems to be oleic, and the yellow one is linoleic. Both reacted acid to litmus paper. An attempt was made to obtain the weight of the soluble fatty acids. The acidified liquid was first separated from the insoluble fatty acids, and the dis- tillate exactly neutralized by normal caustic soda, using phenolphthalein as an indicator. The washings from the insoluble acids were now added to the contents of the fiask and again distilled to a small bulk. This distillate like- wise was neutralized with normal caustic soda. The two distillates were evaporated to dryness to constant weight. The number of centimetres used in the neutralization was multiplied by 0.022, and the product subtracted from the constant weight. The result was unsatisfactory. Each fruit bears a single fiat stone which undoubtedly contains the oils. We obtained in all 14.5667 grams of oil from 225 grams of the original fruit or 6.47 per cent. THE PROTEINS. Some of the berries were crushed and boiled in distilled water for a short time. A small amount of this solution was heated with nitric acid, giving a yellow color, which became an orange red when made alkaline. This showed the presence of albumen. IOWA ACADEMY OP SCIENCE 149 A portion of the fruit was heated with an excess of soda-lime in a dry test tube. The fumes reacted alkaline to litmus paper. A similar effect was pro- duced by heating the berries alone at a high temperature. The nitrogen was determined by the Kjeldahl method; 2.0933 grams of the berries gave 0.0112 gram of nitrogen, equivalent to 0.53 per cent. A quantity of solution which resulted from boiling the berries in distilled water was tested to learn if the albumen contains sulphur. We treated a solu- tion of lead acetate with caustic soda until the precipitate which first forms is redissolved. The fruit solution was now added to this and heated to boiling. A dark colored precipitate of lead sulphide formed which indicates the presence of sulphur. THE ACIDS. The acid tests were made from the sugar extraction. Tartaric and citric acids were found, with a small quantity of malic acid. Citric acid seemed to predominate. IOWA ACADEMY OF SCIENCE 151 SIGNIFICANCE OF THRUST-PLANES IN THE GREAT BASIN RANGES. BY CHAEELS E. KEYES. For more than a generation no other hypothesis of the rearing of the mountain ranges of the Great Basin has been countenanced except that of simple normal faulting on a gigantic scale. This is the explanation offered by Gilbert*. It has its foundation in the observations made by this investigator in the Grand Canyon region of Arizona. While faulting is widely known in the Great Basin country, it is one of the most surprising of facts that few fault-lines have ever been discovered at the foot of the Basin ranges. Whenever the greater lines of displacement are located it is almost invariably the case that they are not at the base of the mountain ridges, but at a distance of several miles out on the adjoining plaint. The mountains are in the main symmetrically developed. The longer ridges have usually a distinct bilateral symmetry. These facts are suggestive of some inattention to the time-factor of the major faulting. In the majority of cases in which critical evidence has been adduced the dates of the principal displacements are not nearly so recent as had been assumed. Instead of being quite late geologically the period appears to be quite early. Probably most of the more profound faulting took place in Jurassic times. While with- out question fault movements^ have been continuous since the beginning of Mesozoic times, and are even now in progress as Spurrt has lately noted, the main displacements are ancient. Recent investigations have had especially in mind the determination of the dates and of the kinds of the various crustal adjustments in the Great Basin country. On the whole, the later movements of the great rock-masses appear to be largely the result of compressive rather than of normal strains. The infolding of old lava-sheets in deposits of Eocene, Miocene, and Pliocene ages, in the Death Valley district of eastern California, for instance, is particularly suggestive. Similar marked flexing of Tertiary strata is now known in many other places in the same region. The compressive character of the acquired geologic structures is especially well indicated by certain enormous thrust-planes which have been recently noted. Although the exact dates of some of these phenomena are not as yet clearly flxed the positions which some of them occupy seems to point to the fact that the accompanying movements may have had much to do with the rearing of the mountains themselves. The importance of the recognition of the presence of thrust-planes in many of the desert ranges lies in the inference that *Geog. and Geol. Expl. and Surv. W. 100 Merid., Prog. Kept., p. 48, 1874. tBull. Geol. Soc. America, Vol. XIX, p. 63, 1908. IBull. Geol. Soc. America, Vol. XII, p. 217, 1901. 152 IOWA ACADEMY OF SCIENCE we may kave to ascribe to tbe mountains of the region generally, .even when normal faulting is in evidence, an initiatory genesis through reversed faulting. Second only in importance to this important observation is that of the possible radical difference in expression of compressive strains in great rock- sections composed entirely of brittle masses and these of masses made up of alternating beds of weak and resistant rocks, especially when the former greatly predominates. Through great compression the tectonics of the western country would thus be quite distinctive from that of the eastern, or Appa- lachian, field. In the last mentioned region the rock-masses include numerous thick zones of yielding shales. Under compression from the sides such masses would easily flow, as it were, enabling the more rigid and brittle layers to become severely flexed into a series of close folds without loss of their con- tinuity. In the Great Basin region there are practically no shale beds except the late clays. In the entire Paleozoic section, which is upwards of 15,000 feet in thickness, there are very few layers that would yield to flexing. Under these conditions folding would in any case be very slight. With brittle rock- masses only breakage and shearing would be possible. As shown by Irving* for the Wisconsin region, great movement in such rocks, is likely to take place only through a narrow belt. Thousands of feet of movement may be expressed within a space of a few hundred feet with no other break within a distance of many miles on either side. In the desert region of the West the conditions are not so‘ favorable as they might be for obtaining critical evidences bearing upon this point. The foots of the mountains are almost invariably covered by ever-shifting loose materials. So far as known the desired data have never been especially sought. The only published suggestion that is now recalled of this mode of mountain origin is in the cases of the Sierra de los Caballos, the Sierra Oscura, and the Sierra San Andreas, in south-central New Mexicot. If the thrust be the true explanation of some of the Great Basin ranges then the mountains of this region are not to be put in a class so very different from that to which the Appalachians and the Juras belong. The specific difference is only in the character of the rocks composing the mountains. This, however, may give rise to very diverse geologic structures. It is also now known that there have been great tortional movements in many parts of the American arid region, by which long ranges have undergone con- siderable lateral displacement. Abundant evidences of this phenomenon are to be seen in the Sandia and Manzano ranges, and in the Caballos, Cochillo and Fra Cristobal mountains!. This phase of the subject is of very great in- terest and is worthy of careful and extended inquiry. *U. S. Geol. Surv., 7th Ann. Kept, p. 390, 1888. tJoumal of Geology, Vol, XIII, p. 64, 1905. tProc. Iowa Acad. Sci., Vol. XII, p. 163, 1905. IOWA ACADEMY OP SCIENCE 153 OROTAXIAL GEOLOGIC CORRELATION AND DIASTROPHISM. BY CHAELES E. KEYES. Exact stratigraphic correlation is today bothering the geologist more than any other subject relating to earth knowledge. This phase of geology has, indeed, been a constant source of embarrassment ever since the science’s birth more than a century and a half ago. A hundred years ago William Smith, an English engineer, discovered the use of organic remains in the determination of the relative ages of rocks; and since his time fossils have been very gener- ally depended upon in unravelling the geologic history of the various parts qf the globe. During the last quarter of the last century stratigraphy began to demand quantitative, instead of merely qualitative, results. Other stratal criteria of a critical character were found to be, in the field, of even greater practical value than the fossils could ever hope for. At the present time most of the geological surveys have adopted a lithologic standard for the geologic unit in mapping; and the fossils come to have only a secondary importance, or are ignored altogether. Even this scheme has not proved to be so satisfactory as was anticipated. It is now quite manifest that we shall have to seek more fundamental criteria in the interests of exact geologic correlation. We shall have to look more carefully into the factors which control sedimentation, which modify it, and which delimit the geologic terranes. Every classification of natural objects is very simple and very perfect so long as we make no comparisons with other methods and do not adopt any other criteria. For example, we may classify plants by means of their fiowers; or by their leaves. We may arrange systematically the mammals according to their teeth. So, also, we may construct an elaborate stratigraphic scheme in accordance with the contained fossils and have, to all appearances, not only a complete but a seemingly flawless plan. This for the last hundred years the paleontologist has tried to impress upon us. It is, however, a classification of organic remains and not necessarily of geologic formations. When we make comparisons with other standards, which seem equally critical, the shortcomings of the paleontologic method become alarmingly glaring. When closely examined the paleontologic scheme of geologic classifica- tion is found to be not a classification of terranes at all, nor a logical arrange- ment of historic events, but merely a rather imperfect grouping of faunas. The question arises whether in stratigraphy we should not be better off today if we were to ignore the fossils altogether, or recognize them only in the most general way. At the meetings last winter in Baltimore of the American Association for the Advancement of Science, and of the Geological Society of America, there was 154 IOWA ACADEMY OF SCIENCE a notable symposium on geologic correlation occupying the time for several days. This fact alone is indicative of the great interest which is being taken in the subject at the present time. The most suggestive paper of all, perhaps, was the one presented by Professor Chamberlain, of the Chicago University. In it was urged the use of diastrophism as an ultimate basis of geologic corre- lation. This is essentially the utilization of the expressions of the local changes in elevation or depression of the surface of the globe, particularly along the sea-coast, due to mountain-making and epeirogenic movements. Now, it may be ^of no little interest at this time to recall the fact that eleven years ago there was read before this Academy a paper* on this very subject. It was entitled “Some Physical Aspects of General Geologic Correlation.” This paper was a more mature consideration of an article published in the American Geologist three years beforet, and called “Orotaxis; A Method of Geologic Correlation.” Since that date I have referred on several occasions specifically to the subject!, particularly in treating§ of the “Orotaxial Significance of Cer- tain Unconformities.” As originally stated** the definition of orotaxis, or stratigra,phic correlation upon the basis of diastatic, or diastrophic, movements is essentially as follows; “The immediate causes for the changes between the relations of the land and sea areas are to be sought in orogenic and epeirogenic movements. As the two kinds of movements cannot be readily separated practically, and as it is of small advantage to separate them theoretically, the results produced may be all regarded as arising from the one cause — that is, from mountain-making forces. The greatest and most abrupt modification in sedimentation, and con- sequently in lithologic, faunal, and, in fact, all characters, are those connected directly with diastatic change, producing depression of some land areas below,< sea-level, and the uprising of other districts above the level at which they once stood, to form those great features of the earth’s surface called mountains. Geologic chronology, therefore, is believed to find ,a true and rational basis in those changes which primarily govern sedimentation and which are intimately connected with the genesis of mountain systems. It is proposed, therefore, to emphasize this factor as fundamental in the marking out of the leading subdivisions of geologic time and to define general stratigraphic succession in accordance with the cycles of orogenic development, calling the classification, or the fundamental principle of correlation, a systematic arrangement of mountains, or orotaxis.” By the term mountains is meant not alone those geographic features which at the present time rise so majestically and conspicuously above the earth’s surface, but also all of those remnantal structures which have been in the past ' prominent characters in the surface relief and which, geotectonically at least, are still mountains, though perhaps now completely planed off and buried be- neath later sediments. With these old mountains the cycles of orogenic deve- opment are properly regarded as extending from the time when the strata first were flexed, through the periods when they were bowed up, then planed ofC nearly to sea-level, and submerged, perhaps, until new degredational products *Proc. Iowa Acad. Sci., Vol. VI, pp. 131-154, 1899. tAmerican Geologist, Vol. XVIII, pp. 289-303, 1896. JSee; Science, N. S., Vol. XII, p. 146, 1900; also. Bull. Geol. Soc. America, Vol. XII, p. 175, 1901. §Am. Jour. Sci. (4), Vol. XXI, pp. 296-300, 1906. **American Geologist, Vol. XVIII, p. 298, 1896. IOWA ACADEMY OP SCIENCE 155 were deposited upon their upturned edges. The completed cycle of mountain- making is the measure of orotaxial chronology. The division-planes cutting the geological column into series, terranes and the smaller subdivisions are actually, as well as theoretically, the lines of unconformities and their represen- tatives. In the cases of the more extensive features of discordant sedimenta- tion they represent no doubt base-leveled surfaces, or peneplains. As a concrete illustration there is probably no better one than that pre- sented by the stratigraphy of the southern end of the Rocky mountains. There are in the geologic column more than a score of well defined terranes having the taxonomic rank of series. With possibly one or two exceptions they are all separated from one another by marked planes of unconformity. The most exact means of correlation over wide areas are given. Of not the least interest are the comparisons that are able to be made with the geologic sections both to the eastward in the Mississippi valley and to the westward in the Great Basin region. Figure 1. Oscillation of Continental Sliore Lines. In the domain of geologic correlation the most important deduction of recent years is that there is an erosional history of continental borders equally sig- nificant as that expressed in the sedimentary record. At best the sediments present only one-half of the stratigraphic history. The historical testimony of the fossils is not only fragmentary so far as the sediments in which they occur are concerned but it gives no suggestion of the erosional sequence of events which are of even greater consequence. If we represent in diagram (Fig. 1) an ideal cross-section of a continental border, complete sedimental history stands at one side (section A), and com- plete erosional history at the other side (section C). In terms of the sedi- ments the latter is an hiatus, or as the older text-books on geology call it a time-gap. The section B represents about as much of the complete history as the fossils ordinarily record. In reality the history which organic remains portray is merely that of faunal sequence, with no necessary relationships of physical episodes suggested; in its entirety it is only a small and imperfect fragment of the actual record of geologic events. The zig-zag line may be further taken as indicating the oscillations of a shore-line; and also the course of the migration of a specific fauna during geolo- 156 IOWA ACADEMY OF SCIENCE gic time. At B, where the biologic section is made the point of special inquiry, the recurrence of faunas is graphically explained. More important than this is the weakness of the biotic method of geologic correlation that is shown; and the great strength and exactness of the correlative methods which are purely physical in character that are indicated. The sedimentative section with its contained fossils stands for the con- tinuous record; while the erosive history represents the rhythmic breaks which make possible exact correlation of terranes and general stratigraphic classifica- tion. The stratigraphic expression of the latter is the unconformity. This again is the outcome of diastatic, or diastrophic, movements, or more impres- sively and more readily recognizable in the field, the results of mountain-mak- ing changes upon the position of the shore-line of the ocean. Systematic ar- rangement of terranes on this basis is fundamental; it is strictly genetic; it is not dependent upon the often more or less fanciful interpretation of fossils; it is directly in harmony with the laws controlling sedimentation inself; it is the most practical and exact of any method yet devised; and it enables the votaries of geologic correlation to swing entirely clear of paleontology. The nicety and rapidity with which the orotaxial principles act in practice are indicated by a number of concrete examples. In the Upper Mississippi valley the values of the different methods of geologic correlation have been recently specifically compared.* In the Ozark region the shortcomings of the older methods of geologic classification have been pointed out.t Around the southern end of the Rocky mountains, in central New Mexico, the great value of the orotaxial method has been especially emphasized.! Its value has been determined in the unfossil- iferous Tertiary deposits of the Death Valley region in eastern California and Nevada.! Earlier Irving** strictly followed the method in correlating the Pre-Cambrian sequence of the Lake Superior region; and McGeett applied its principles to the unfossiliferous formations of the Atlantic Coastal plain. In the present advanced state of stratigraphical science, in which recon- naisance work is no longer needful over the large part of our country, it seems that we have reached a stage where classification of terranes should follow definite principles in accordance with the taxonomic ranks of the various geologic units, much in the same way that it is accomplished in botany or zoology. A dual geologic classification — one structural and the other biotic — is certainly superfluous. The biotic scheme may be advantageously eliminated entirely as it is now really done in practice by all except the old-school pale- ontologists. We may arbitrarily recognize the larger divisions as worldwide time-divi- sions; and regard the sediments as deposited during certain eras or periods. The latter may also be advantageously subdivided into Early, Mid and Late classes, still retaining the time criterion. Below the taxonomic rank of period, or sub-period, however, geologic sections are provincial in character. The structure sequence of the region now becomes the most critical of the corre- *Proc. Iowa Acad. Sci., Vol. X, pp. 105-107, 1903. tBull. Geol. Soc. America, Vol. XII, pp. 173-196, 1901 ; also, Ibid., Vol. XIII, pp. 267- 292, 1902. !Am. Jour. Sci. (4), Vol. XXI, pp. 296-300, 1906. §Trans. American Inst. Mining Eng., Bull. No. 34, pp. 867-903, 190'9. **U. S. Geol. Surv., 7th Ann. Kept., pp. 437-439, 1888. tfCong. geol. international, 5me Sess., p. 164, 1903. IOWA ACADEMY OF SCIENCE 157 lative criteria. The series is all-important and not its time equivalent, which begins to have very vague definition even when different parts of the same geologic province are compared; and necessarily so in provinces with dissimilar histories. This plan gives prominence to the structural unit of geologic map- ping, the lithologic formation, or terrane. Minor subdivisions of the latter may be delimited by the specific mineral peculiarities of the fossils. By clearly distinguishing between geologic history and biotic history geologic correlation is placed upon a rational, genetic and philosophic foundation. Stratigraphy is immeasureably advanced. tl IOWA ACADEMY OF SCIENCE 159 CARBONIC COLUMN OP RIO GRANDE REGION. BY CHARLES E. KEYES. The character of the later Paleozoic succession in southwestern United States has radically modified our general ideas regarding carbonic history in America. As directly bearing upon this subject the Carbonic rocks of the New Mexican region are of exceptional interest. The Rio Grande section, if it may be so designated, is serially the most complete in the country. It is of great thick- ness. It contains many elements wholly unknown elsewhere on the continent. It furnishes full data with which to close the already prolix debate on the exact a’ge and stratigraphic position of the uppermost Paleozoic beds of Kansas and other parts of the country. It is particularly important at this time as connecting the succession of the Mississippi province with that of the Far West. By contrast it emphasizes the insignificance of our eastern Carbonic representatives. It was recently shown* that while few estimates on the maximum measure- ment of the Carbonic rocks of the Southwest ventured above 2,000 feet there really existed of these sediments in New Mexico the enormous thickness of more than 6,000 feet. Although there have been many notes published on the Carbonic rocks of the Southwest there has never been any serious attempt to correlate the results of the various disconnected observations. Only lately have investiga- tions of broad character made reasonably exact geologic correlation in the region possible. While it is, perhaps, as yet premature to venture beyond the pro- vincial series in the detailed consideration of the Carbonic formations of the Rio Grande region, there are certain terranal names which have long been locally applied that may be used. Some of them were not, possibly, so exactly defined as they should have been originally; but this fact could hardly be a valid excuse for the proposal of new names on no better grounds than the old ones and the use of some of these old names in entirely different senses. From such course only confusion can come. In its latest and most complete form the standard Carbonic section of the Rio Grande region, or of New Mexico, may be indicated as follows: *Journal of Geology, Vol. XIV, p. 147, 1906. 160 IOWA ACADEMY OF SCIENCE GENERAL RIO GRANDE SECTION OF CARBONIC TERRANES. Time Divisions Provincial Series Formations Rocks DATE Cimarronian Moencopie Shales Sandstones Pecos Shales Guadalupan CnpifaTi Limestones Eddy Sandstones MID Maderan Bernalillo Shales Hueco (upper).— Oscuro Limestones Limestones Manzanan MO'Sca — —J— Coyote Montosn Limestones Sandstones Limestones Sfludia Shales Ladronesian Alamito Shales EARLY Socorran Sierra Lake Valley Grande Limestones Limestones Limestones The presence of marked planes of unconformity between all of the several serial divisions is especially significant. It points to still other unknown and important representatives to make the American section complete. How great are the terranal representatives of these intervals can at present only be sur- mised. In northern New Mexico the unconformity plane between the Maderan and Cimarronian series is known, 200 miles to the southward, to be represented by over 3,000 feet of sediments. The remnants of the true coal-bearing series, corresponding to the lower productive coal measures of the Mississippi valley is believed to have been once of great thickness and extent. Under similar conditions an erosion interval north of the Ozark dome at the base of the Des Moines series is known to be represented farther south in central Arkansas by sediments the thickness of which is more than 10,000 feet.* * In the South- west the depositional equivalents of the Carbonic unconformities may equal or even greatly exceed in thickness that of the present known section. The Socorran series corresponds in a general way to the lower part of the original Mississippian series of Missouri and Illinois. The Ladronesian, Man- zanan, and Maderan series might be included in the world-wide Pennsylvanian division of the United States Geological Survey. The Guadalupan and Cimar- ronian series have no representation in the East; and the latter in the Missis- sippi valley only in western Kansas. Three important subdivisions of the Socorran series have thus far been recognized.! These find their best development in the vicinity of Lake Valley, in southwestern New Mexico. There are good reasons for believing that other formations of this series exist nearby. These formations are the Grande, Lake *The heavy lines indicate planes of unconformity. The Eddy sandstones may more properly belong to the Maderan possibly co-extensive with the Bernalillo shales and sandstones ; there are reasons for believing that marked line of unconformity exists at the base of the Capitan limestone. All of the unconformities represent erosion epochs, except that between the Maderan and Manzanan which is apparently an overlap. There are several planes of unconformity in the Maderan section. *Bull. Geol. Soc. America, Vol. XII, pp. 173-196, 1901. tTrans. American Insti. Min. Engin., Vol. XXXIX, 1908. IOWA ACADEMY OP SCIENCE 1'61 Valley and> Sierra limestones. The Lake Valley limestone, carrying the typical fauna of the- Lower Burlington limestone was originally fully described by Springer.! . Its northward extension to the Magdalena range, 100 miles away,, was recently noted. § Herrick’s title** “Graphic-Kelly lime,” for a part of this formation, that has crept into geologic literature during the past year, was not intended to have exact geologic definition but merely local mining significance, referring, to mines of that name. . The Grande limestone appears to. contain the, fauna of the Chouteau limestone of. Missouri. The Sierra limestone is a for- mation higher than a.ny other of the Early Carbonic strata yet recognized in the Southwest. Gordon is mistaken in regarding all three of these divisions as the original Lake Valley limestone. The only known Carbonic- coal-bearing formation in the Southwest is included, in the Ladronesian series. It is thought to be an extension or representative of the Arkansan series of the southern Ozark region. Being sharply delimited above and below by marked unconformity planes of erosional character it was doubtless once one of the most important formations of the region. Her- rick,* *, who first noted the beds, though not recognizing their true significance,, referred them to the Upper Carbonic, but he subsequently was convinced that they w^ere of earlier age. The series will doubtless be found to be wide-spread though possibly only in remnantal areas. t No one who has seen the two for- mations w^ould think of correlating the beds of this series with any part of the Sandia shales. Its fauna and flora ia a theme of great interest as it must be so unlike anything else in the West. It is a matter of great surprise that the recent considerations of the beds constituting the Manzanan series should give rise to such a confusion of ideas as they have. It can only be accounted for by the cursory and incomplete character of the examinations during hasty reconnaisance work which has been the usual method in the region. The use of the term Mamzanan is an, attempt to preserve Herrick’s title without introducing new names. To be sure, it was not at first definitely delimited, but since no other title for the beds in question has intervened there appears no good reason for abandoning the term, or for using it for a very different section having no elements in common with the first one. As he himself has often in person explained, Professor Herrick in none of his published writings ever intended to formally propose any of the geolographic names wdiich he used provisionally. The formal proposals of the necessary geologic titles and their definition was reserved for a special memoir which I believe v/as well along towards completion at the time of his sad demise. The intentionally informal character of the few geographic names he use . from time, to time is clearly indicated in all of his v/ritings. His term Manzano, for ex- ample, is used in a number of different senses in as many different places; one referring to the gray limestones between the red-beds and the red quart- zite at the top of his Sandia shales. The title Bernalillo shales, which I had suggested for the Mid-Carbonic red-beds, was acceptable to him and would have been used by him in his final memoir. lAm. Jour. Sci. (3), Vol. XXVII, p. 102, 1884. §Proc. Iowa Acad. Sci., Vol. XII, pp. 169-171. 1905. ** American Geologist, Vol. XXXII, p. 311, 1904. *Journal of Geology, Vol. XII, p. 242, 1904. tEng. & Min. Jour., Vol. LXXXI, p. 1129, 1906. II 162 IOWA ACADEMY OF SCIENCE If the gray and blue limestones below the Bernalillo red shales of the Sandia district (Manzanan and lower Maderan) are to be thown together, which does not seem at all advisable, the term Magdalena Group as recently proposed* is clearly synonymic. Richardson’s title of Hueco groupt covers this section ex- actly, and has the great advantage of being at least recognizably defined. The Maderan series appears to be separable from the Manzanan upon the same faunal and other grounds as the Missourian and Oklahoman series in Kansas. Its development is that of a three-fold sequence. As exposed in the north, in the Sandia mountains the main limestone member is only 400 feet in thickness. Higher and higher limestone beds come in southward until a max- imum measurement of 3,000 feet is attained. This superior dark limestone formation, or median member of the series, is included in the Hueco forma- tion of Trans-Pecos Texas. If the name Hueco is to be retained as a geologic title it may advantageously be applied to the median members as representing the main body of limestone of western Texas. The third and youngest member of the Maderan series is composed of shales and sandstones having a characteristic red coloration. The title Bernalillo shales has been applied to them.t The fact that the “Red-Beds” are not of Permian nor Jura-Trias age is not a new discovery as lately announced by Lee.l As early as 1900 Herrick** had found abundant fossils in these beds which were correlated with the so-called Permian (Permo-Carbonic) of Kansas. It must be remembered that all of this author’s later references to the Permian are to this so-called Kansas Permian and not to the true Permian. About the first revision which my own preconceived notions of the region underwent when first I visited New Mexico in 1902, was that these Red-Beds of the Rio Grande region corresponded faunally to the Oklahoman series of Kansas. They were thus specifically correlatedtt and their distinctness from the Kansas Red- Beds emphasized by the designation of the local title of Bernalillo shales. At the time it was thought that the upper one-third of the red-beds section might be a part of the Cimarronian series; but it w^as soon afterwards discovered that over thi. part of the region of central New Mexico both the Kansas Red- Beds and the Triassic Red-Beds were absent.* In the section east from the Manzano mountains, down the Rio Pecos and Canadian river valleys there are thus found three great red-beds formations imposed upon one another with apparently no sharp planes of separation and belonging to three distinct geologic ages. To avoid confusion I have tried to be always very careful to apply the title Red-Beds only to this great sequence. There are in the region extensive Cretacic “red-beds,” which I have always referred to as the Pink beds, or Ter- tiary “red-beds,” and farther south great Devonian “red-beds,” which I have not designated at all. To further complicate the Red-Beds problem southward from the Sandia locality the sandy materials rapidly increase and the red coloration fades, as it does in the Red-Beds region of Kansas and Oklahoma. In the 150 miles ^Journal of Geology, Vol. XV, p. 812, 1907. -fUniv. Texas Min. Sur., Bull. 9, p. 32, 1904. tOres and Minerals, Vol. XTI, p. 48, 1903 ; also. Kept, of Governor of New Mexico to Secretary of Interior, for 1903. p. 339, 1904. gJournal of Geology, Vol. XV, pp. 52-58, 1907. **Journal of Geology, Vol. VIII, p. 116, 1900. iiLoc. cit., p. 339, 1904. *Amer. Jour. Sci. (4), Vol. XX, pp. 423-429, 1905. IOWA ACADEMY OP SCIENCE 163 which separate the Sierra Osciira and the Guadalupe range, which I have iioi yet been over thoroughly, a grave question arises as. to what becomes of the red Bernalillo shales and sandstones. I have fancied sometimes that the 1,500 feet of Richardson’s Delaware Mountain sandstone (Eddy sandstone) which im- mediately overlies the dark Hueco (Maderan) limestones is the southern con- tinuation; but of this there is as yet no strong proofs. I had also thought that I had traced the Cimarronian Red-Beds of western Kansas and northwestern Texas up the Canadian River valley and down the Pecos valley, around the great escarpment of the Llano Estacado, to the vicinity of the Guadelupe mountains where presumably they rested on the Guadelupe limestone. While on account of the extensively faulted character of the area it may take further field work, in order to determine this point beyond all question there has yet appeared no valid grounds for believing that these Red-Beds underlie the Guadalupe limestones. The existence of a dark limestone, 800 feet in thickness, above the Berna- lillo shales, as urged by Lee* and by Gordont I very much question. There will have to be very much better testimony adduced before their ascertion can be accepted. My own observations have been strongly to the contrary. I am quite familiar with all of the localities mentioned by both of the authors named. In every instance there seems to be very clear evidences of profound faulting which has raised, as it were, the lower limestones above the outcropping level of the red shales. In the San Filice range, east of Socorro, the fault has been tested by the drill and a displacement of nearly 1,000 feet found, yet along the faultline there is practically no bending of the strata. Similar apparent fault- ing back of the Sandia and Manzano ranges, v^^here Lee states that the great upper dark limestone is missing, brings the lower limestones above the level of the same shales, in the same way as it does in the Caballos, Oscura and San- Pilice ranges. Small wonder is it that Girty comments with surprise upon the similarity of the fossils which were collected for him from the limestones be- neath the Bernalillo shales and the alleged limestone above. Late Carbonic time is represented in the Rio Grande region by the great Guadalupan series of limestones, the faunas of which were early described by Shumardt and later by Girty§, but which have no counterparts elsewhere on the American continent. Their affinities are Avith the original Permian series of Russia.** The other Late Carbonic representative is the true Cimarronian series of Red-Beds of Kansas, separated from the Triassic red-beds by marked unconformitytt. *Journal of Geology, Vol. XV, p. 54, 1907. tibid., p. 816, 1907. tTrans. St. Louis Acad! Sci., Vol. I, p. 280, 1860. §Univ. Texas Min. Sur., Bull. 9, p. 40, 1904. **Journal of Geology, Vol. VII, pp. 321-341, 1899. ttAm. Jour. Sci. (4), Vol. XX, pp. 423-429, 1905. I IOWA ACADEMY OF SCIENCE 165 THE HYSTERESIS LOOP. BY D. W. MOEEHOUSE AND HAEEY EAY WOODEOW. It is not proposed to introduce a new method for the determination of the hysteresis loop, but to introduce some advantageous modifications. The method is similar to the ring ballistic method outlined by Dr. R. A. Millikan. This method has the advantage over the old magnetometer method in that the lines of force are continuous through the iron. It cannot be used hov/ever if the iron is hard and causes any creeping. The revolving commutator is a plain application of the mercury cup com- mutator with which we are all familiar. The variable resistance is an applica- tion of the common resistance box, using knife edge sv/itches in place of the plugs. This gives a continuous current which can be increased or diminished by the throw of the switches. The current was increased by small steps and the value of the current taken by a potentiometer as the most accurate ammeter will not detect the small changes. The Induced current was measured by the throw of a ballistic galva- nometer and the throw evaluated by means of the earth inductor. The value of the magnetizing field increased more rapidly than the induct- ance until (H) reached the value of about two gauses, then the inductance increased much faster than (H), until (H) reacfhed the value 5.068 gauses and from this point the ratio of (B) to (H) became smaller and smaller and ap- proached zero as a limit making the curve approach a straight line parallel to the X axis. As the current decreased the curve crossed the Y axis at (B) = 10,486 lines, giving 73.3 per cent for the retentivity. When the current was reversed the curve crossed the X axis at — 3.03 gauses which is the coercive force. ; IOWA ACADEMY OF SCIENCE 166 DATA FOR THE HYSTERESIS LOOP. I + .055 .063 .0?2 .085 .095 .m .143 .170 .204 .266 .353 .472 .620 .718 .621 + .621 .472 .350 .264 .204 .171 .143 .124 .108 .097 .083 .062 .055 .000 — .055 .062 .073 .125 .142 .167 .205 .350 .468 .609 .714 d +3.58 1.05 2.00 5.80 5.70 5.69 4.68 3.60 1.95 — .08 1.30 1.50 1.55 1.75 1.10 .55 .50 .45 5.10 -^.00 1.60 5.68 10.33 15.90 17.30 13.25 10.70 9.84 7.58 6.50 5.. 50 2.13 Sum. d. V equals .570747. + 3.58 Radius of ring:, 4. 75 cm. 4.63 Coil, 590. turns. 6.63 Test coil 75. turns. 11.71 Earth inductor 1000 turns. 16.01 Radius of E. In. 7.7 cm. 22.01 Radius of teste. .717 cm. 28.69 Mean d was 8.36 cm. 34.49 39.79 45.07 H B u 50.77 56.46 3.553 61.14 5.068 64.74 17.61 66.69 I +65.84 —.608 64.59 .467 63.09 .348 61.54 .261 60.10 .203 69.09 .168 58.21 .143 57.51 .124 56.91 .110 53.36 .096 55.86 .086 55.36 .071 54.66 .034 54.21 .054 49.11 .000 —40.11 +.054 38.51 .063 35.51 .1073 29.11 .087 23.43 .097 13.10 .109 — 2.80 .124 20.10 .142 33.36 .169 44.05 .204 53.89 .262 61.47 .350 67.97 . 466 73.47 .606 75.60 .709 7230.5 2036.6 max. 9453.0 1865.5 13920.0 790.3 d Sum. d. + .80 —74.80 1.30 73.50 2.45 71.05 1.40 69.65 1.30 68.35 1 .02 67.33 .80 66.53 .70 65.83 .60 65.23 .55 64.68 .49 64.19 .90 63.29 .62 62.67 .42 62.25 5.20 57.05 +9.42 —47.63 1.70 45.93 3.18 42.75 6.50 36.25 5.67 30.58 10.40 20.18 15.90 +41.28 17.45 13.17 13.00 26.17 10.27 36.44 9.30 45.74 8.02 53.76 6.10 59.86 4.30 64.16 2.20 66.38 IOWA ACADEMY OF SCIENCE 167 THE GOOGLER PRIMARY BATTERY. BY IIAERY RAY WOODROW. The cell furnished us by the Battery Company was of the two fluid type. The exciter was sulphuric acid and zinc and the depolarizer was principally nitric acid. It resembled very much the Groove and Bunsen cells but differed in the depolarizer, which contained ferric sulphate. The carbon was placed inside the porous cup surrounded by 450 c. c. of the depolarizer. Outside this was 2,000 c. c. of sulphuric acid and a round cylinder of zinc. The mercury served the purpose of keeping the zinc amalgamated and also in making con- tact with the external circuit. In the chemical analysis I found iron and a slight trace of zinc in the depolarizer but no metal in the exciting fluid. Both solutions were acid which proved to be nitric and a small amount of sulphuric in the depolarizer and only sulphuric in the exciting fluid. It was at once evident that the iron in the depolarizer was in the form of ferric sulphate which gave the solution its brown color. It is to be noted that this brown color turned to green as soon as the action began in the cell. The hydrogen reduced the ferric sulphate and then the nitric acid oxidized the ferrous sulphate. The object of this was to make the action milder and fewer nitrous fumes would escape. The quantitative analysis of nitric acid is best determined by titration and the sulphuric acid is determined very nicely by precipitating the sulphate with barium chloride and weighing the precipitate as barium sulphate. From this data the amount of sulphate (s) can be determined by the formula: s = abd ce (1) where (a) is the molecular weight of (s), (c) the molecular weight of the weighed precipitate, b the weight of the precipitate, (d) the total volume of the solution in the battery, and (e) the amount taken for determination. The sul- phate is not all in the form of sulphuric acid but some of it is combined with the iron and zinc. The iron was determined by precipitating it as ferric hydrate and weighing it as ferric oxide. The amount of iron is found by formula (1) by usng the values of a, b, and c which correspond to iron and ferric oxide. Formula (1) may be simplified by the use of the chemical factor (f) which is equal to a — c. log. (s) = log. (b) + log. (f) + log. (d) — log. (e) (2) The zinc was determined by precipitating it as a corbonate and weighing it as an oxide. After the amount of zinc and iron is known it is a simple matter to determine the amount of sulphate (k) combined with them by the use of the formula: k -= os g (3) where o is the molecular weight of sulphate, s the same as in formula (2) and g the atomic weight of the metal (s). 168 IOWA ACADEMY OP SCIENCE We can now subtract the amount of sulphate combined with the iron and zinc from the total amount and the remainder will be the amount combined with hydrogen to form sulphuric acid. j = kl - m (4) given the amount of sulphuric acid; when k is the amount of available sul- phate, 1 the molecular weight of sulphuric acid, and m the molecular v/eight of sulphate. As v/e have the amount of sulphuric acid we can nov/ proceed to find the amount of nitric acid in the solution. As was said before this can be done by titration with a hydrate, but we must remember that the sulphuric acid will require some of the hydrate to neutralize it. I therefore subtracted the amount of potassium hydrate, as I used potassium hydrate for titration, re- quired to neutralize the sulphuric acid in the portion used. The remainder was the amount used in neutralizing the nitric acid. Methyl orange was used as an indicator as it changes color from the acid to neutral solution. The amount of nitric acid (N) is determined by the following formula: N = ACEd - Be (5) A is the molecular weight of nitric acid, B the molecular v/eight of potassium hydrate in one c. c., C the number of c. c. of potassium hydrate used against nitric acid, and d and e the same as in formula (1). We now have determined the amount of zinc sulphate or zinc, ferric sulphate or iron, sulphuric acid, and nitric acid in the depolarizer. The outer solution was much easier analyzed as it only contained sulphuric acid at first and later on zinc sulphate and sulphuric acid. I determined these the same way as I did in the depolarizer. In order to find the chemical action it was necessary to take out ten c. c. of both solutions every six hours and analyze it. This was done and the results are tabulated in data 3, A very essential thing to know about a cell is its action on open circuit. I let the cell stand for forty-eight hours on open circuit and the action was slight and much more in the zinc and sulphuric acid than on the nitric acid, there being 25.2 grams of zinc dissolved, 36 grams of sulphuric acid used and 1.4 grams of nitric acid reduced. I took the E. M. P. of the cell by means of the Leeds Norturup potentia- meter, type K, and found it to be 1.8935. The next step was to find the internal resistance of the battery in order to know what external resistance would give a current of about nine amperes. The condenser method was used and the internal resistance B found by the formula: B = S(d'— d") - d" (6) Where S is the resistance in shunt, d" the throw on charge or discharge shunted, and d' the throw on charge or discharge. The throw is proportional to the voltage, and d' represents the E. M. P. and d" represents the P. D. with an external resistance S. Thus we see this method is only a simplified one of the regular fall of potential method, whose formula is: B = ( (E-V) -V) R or B equals (E-V) - C (7) I found the ohmic resistance to be .0710. I used the condenser method in finding the internal resistance on recovery and the fall of potential method when the battery was running on closed circuit. Having found the internal resistance (B) to be .0710, I used the formula: c = V (r b) IOWA ACADEMY OF SCIENCE 169 in order to find the value of r necessary to make c about nine ampers. I then put r to about this value and measured it exactly with the postofRce bridge. I measured the E. M. P., the P. D. and current by the potentiameter every hour until the battery was run down. The E. M. P. and P. D. are measured directly^ on the potentiameter while the current is measured by measuring the potential difference of .01 of an ohm resistance in the circuit. Then c equals v' ^ r = v' .01 equals lOOv' (8) These results are tabulated in data 2 together with the temperature of the room, the internal and external liquid, and the internal resistance as figured out by formula (7). Having the chemical action, we are now in a situation to calculate the E. M. P. when 96,550 colombs of electricity possess one gram equivalent of each ion. One colomb is lO-’^ c.g.s. units and one volt is 10® c.g.s. units. Therefore one colomb of electricity will correspond to 10^ E ergs and 96,550 colombs will equal to 96,550x10' E ergs. We will now assume that all the energy due to chemical action is converted into electrical energy. If we let m equal the amount of heat evolved by the action of sulphuric acid on one equivalent of zinc and n equals the amount of heat evolved by the reduction of the acid. Then the work done in ergs by the chemical action is (n+m) 4.2x10^ for 4.2x10^ is the value of a calorie in ergs. As we have both the electrical energy and chemical energy in ergs and assume them to be equal, we have 96,550xl0‘E' = (n+m) 4.2x10^ Thus E' = ( (n+m) 4.2) - 96,550 (9) One gram atom (63gms.) of zinc dissolved in sulphuric acid evolves 38,066 calories of heat. Zinc is a diad and consequently one equivalent (63^2 gms.) evolves 19,033 calories of heat and is the value of m. In taking up the value of n, a more difficult problem confronts us. The nitric acid is reduced in several different stages. The two principal equations of formations are: HNO3 + Ho = HNO2 + H,0 + 41013 calories, and HNO3 + H = NO, + H2O + 26966 calories. Besides the reduction of the nitric acid in these two ways, the brown fumes of nitrogen pentoxide showed that some of the nitric acid was broken up into nitrogen pentoxide and water. 2MNO3 = N2O5 +H0O — 7330 calories. We do not know the amount of each formed, but we can calculate the average during the interval of six hours. We know the quantity of zinc (x) dissolved and the quantity of nitric acid (P) used. It 'will he necessary to consider that just two of these actions occur at once and, as HNOo will not be found when N0O5 is liberated, this will be permissible. If we let X equal the amount of zinc dissolved, y the hydrogen liberated, P the HNO3 used, r the HNO3 reduced to HNO2, and a the hydrogen liberated which reduces the HNO3 to HNO2. Then P-r equals the HNO3 reduced to NO, + H2O and H-a the hydrogen used with it. Then 65-2 = x-y (10) 63-2 = r-a (11) 63-1 = (P-r) (y-a) (12) Eliminating a and y equation (10), (11) and (12) r = 126x - (65-P) (13) 170 IOWA ACADEMY OF SCIENCE If r comes out minus we consider that no HNOg is formed and proceed to determine the HNO3 used for N2O5 and NO2. To determine this we calculate the amount of HNO3 used for all the zinc and subtract that from the HNO3 used and that leaves the HNO3 decomposed into Hg and N2O5. These results are tabulated in data No. 4. As we have the ratio of the different reductions of the HNO3 we can deter- mine n and then the calculation of E' is very simple by subtracting in equa- tion (9). This is done for the five intervals of time and tabulated in first part of data No. 7. In calculating the E. M. F. (E') of the cell at different times we have not taken into consideration the temperature coefficient (deldt) which must enter into the equation for the time calculated E. M. F. We must now direct our attention to the temperature coefficient (de|dt). In doing this we will let H' equal to the amount of heat supplied (in ergs) at the temperature T' and H" the heat subtracted at the temperature T". Then (H'— H" H' = (V —T") + T' H' — H" is the quantity of heat used and is equal to O" (E' — E") ; where O" equals the units of electricity passed at T' and T" and E' and E" the E. M. F. at T' and T". Therefore O" (E'— E") - H' = (T'— T") 4- T' thus H' = O" T' (E'— E") -4 (T'— T"). (E' — E") 4- (T' — T") is the rate of change of the E. M. F. of cell with tempera- ture and we will designate it by de4-dt. By letting O" equal to unity the equa- tion reduces to H = T (de-4dt) (14) Which is the quantity of heat converted into electrical energy during the passage of a unit quantity of electricity. It is to be noted that deldt carries its sign. That is it is plus if it increases with temperature and minus if it decreases with temperature. If H'" is total amount of heat produced by chemical action when one unit quantity of electricity passes through the cell. Then H'" -t- p = E When H'" and p are in ergs. Consequently, H'" 4- de4-dt = E (15) And E is the time calculated E. M. F. of cell temperature T on the absolute scale. Now we will proceed to find de|dt, which is necessary in calculating the time E. M. F. We will represent the current by c and the P. D. at the terminals of cell on closed circuit with external resistance r by e. Then the heat developed in the external circuit in the time t is equal to aect calories, when (a) equals .2387, which is the value of one joule in calories. The heat developed within the cell itself in the time t, by the passage of the current (c) is ar"e^t where v" is the internal resistance of the cell. Therefore (ar"c^t + aect) is the amount of heat developed by the passage of ct units of electricity. E = s e 4- cr" multiply by act acEt = acet 4- ac^rt (16) It will be noticed that each side of this equation represents the energy trans- ferred into heat. IOWA ACADEMY OF SCIENCE 171 If w represents the amount of heat taken up by the cell and also the amount radiated; then w = arV't — actdejdt t (17) Eliminating arV't in equation (16) and (16) and (17) acEt = acet + w + acTdejdt t Hence de^dt = acEt — acet — wjaTct And de-dt = E — e — ar-^act(T) (18) Before we can continue any further in finding de-^-dt, we must find the value of w, which represents both the radiated heat and the confined heat. The first step in finding w is to find the water equivalent of the battery, which is done in the following manner: Weight of jar Sp. H. .198 W.E. 287.3 Weight of carbon ... 956.3 “ .144 “ 135.2 Weight of zinc ...1907.2 “ .093 “ 177.4 Weight of porous cup.. . . . 565.4 “ .206 “ ll-O.S Weight of Fe<,S04 . . . 12.39 “ “ 26.4 “ 2.1 149 Weight of ZnS04 . . . 25.2 “ 26.4 “ 4.13 161 Weight of H2SO, ... 288.33 “ “ .269 “ 77.69 Weight of HNO3 ... 353.7 “ .303 “ 107.20 Weight of H.O ...2124.15 “ “ 1. “ 2124.15 Total water equivalent 3031.62 The specific heat of a sulphate is 26.4 4-M where M is the molecular weight of the compound. We now have the water equivalent of the battery and the confined heat is the product of water equivalent and change in temperature. The radiation constant (a) is the next essential to determine. The battery was heated to a few degrees above the temperature of the room. The tempera- ture of the battery was now 27® and the room 23®. The temperature fell to 25.25® in 45 minutes. Then the total amount of heat lost per hour was 1.75x3031. 62H-.75 which is 7069 calories. Then the quantity of heat (Q) radi- ated, is Q = a(T" — T®") (19) where T' and T® is the temperature of the battery and room on the absolute scale. 7069 = a (8001000000 — 7727000000) log a = 5.4115 — 10 Now in finding the heat radiated we have a, T' and T® given and solve for Q. The value of w is thus figured for the five intervals of time and tabulated in data No. 5. As we have w we can now substitute in equation (16) and find de-:-dt. This is done and tabulated in data No. 6. We now have everything to make a complete calculation of the E. M. F. E. M. F. = E' + Tde^dt. The most Accurate way in determining the efficiency of a battery is to take the total amount of electrical work done in comparison with the total amount of chemical work done. . 172 IOWA ACADEMY OF SCIENCE The accompanying curves are drawn according to the accompanying data. Curve 3, fig. 1, plate 1, is the E. M. P. on open circuit and was very steady after the first few minutes until about three forty, when it suddenly drops. This drop is due to polarization and by looking at data No. 4 we will see that there is more hydrogen liberated at this point than the nitric acid was able to take up. The curve runs along very smoothly until the last hour, where it drops a little and also at this point the nitric acid is practically all gone. The recovery curve 2, fig. 1, plate 1, came up very rapidly at first and then slowly rose until it reached the starting point, where it was very near the calculated voltage of the cell when HNO2 is formed. Curve 1, fig. 1, plate 1, which is the E. M. F. curve on running down again, dropped so fast that it was difficult to take the E. M. F. readings. It dropped to the level of the E. M. P. when the recov- ery curve started and then gradually fell. The potential curve (18) fig. 2, plate 1, agrees very well with E. M. F. curve if we consider curve (c) which is the internal resistance curve. The P. D. falls gradually while the E. M. F. runs along very near the same level. This fall is due to the use in the internal resistance. This curve runs along with the calculated E. M. F. curve (4) fig. 1, plate 1, until it reaches the point of polarization. The drop in the sixth hour is due to the rise in temperature at that time, shown by curve (9) fig. 2, plate 4, for de-^dt is negative at this point. The current curve (17) fig. 2, plate 2, falls faster than P. D. curve because the internal resistance here again enters into the equation. The drop at the sixth hour here is the same as in the P. D. curve, as would be expected. The internal resistance curve (6) fig. 1, plate 2, rises until the nineteenth hour when there is a drop. The resistance that is above the level of curve (7) fig. 1, plate 2, which is the recovery curve of the internal resistance, is due to polarization. The drop here is due to the fact that hydrogen is not liberated so fast 'and the nitric acid can take care of it better. The internal resistance falls immediately on recovery which shows very plainly the polarization resis- tance.- ^ The ’wattage curve (8) fig. 1, plate 4, is a combination of the P. D. curve and the current curve and has their respective characteristics. The temperature curve (9) fig. 2, plate 4, of battery represents the heat developed within the battery and it together with the temperature of room shows the heat radiation. The specific gravity curves (11) fig. 2, plate 3, and (12) fig. 2, plate 3, resemble the HNO3 curve (13) fig. 1, plate 3, and the zinc curve (16) fig. 1, plate 5. The reason for this is the fact that the specific gravity of nitric acid is proportional to its per cent. The action through the porous cup changes this a little and at the end of the specific gravity curve it rises a little, due to the heavier zinc solution coming in. In the outer solution the specific gravity raises in proportion to the amount of zinc brought into the solution. The hydrogen liberated curve (14) fig. 1, plate 3, and the zinc consumed curve (16) fig. 1, plate 5, are the same relative curves as the hydrogen liberated is proportional to the zinc consumed. These are also the same d,s the HoSOi curve only inverted. The zinc consumption curve (21) fig. 2, plate 5, against the wattage repre- sents the zinc efficiency and is equal to the H2SO4 curve (20) fig. 2, plate 5, only inverted. This is true because the amount of chemical work dohe by the zinc and H2SO4 is proportional to the zinc consumed. The wattage, that is watt hours in the case, is the electrical work done. The HNO3 decomposed curve IOWA ACADEMY OF SCIENCE 173 (19) fig. 2, plate 5, does not exactly represent the work done because it decom- poses in different ways and evolves different amounts of heat. The heat watt curve (23) fig. 2, plate 6, is the efficiency curve as x repre- sents the total chemical heat and y the watt hours. Curve (22) fig. 1, plate 6, is the temperature coefficient curve plotted against the time. It starts out a plus dun to the heat taken up in formation of N^-O^ and soon changes to a minus and then contrives to fall. The cell is of no practical good for closed circuit work after the nineteenth hour when polarization sets in. But the cell may be filled with the solution again and be nearly as good as new. It is to be noted that the rougher the zinc gets, due to the chemical action, the higher the local action is. This is due to the fact that the rough dirty zinc will not keep amalgamated. DATA NO. 1. PHYSICAL PROPERTIES. Weight of zinc 1975.7 grams Weight of carbon 956.3 grams Weight of o'ar 1787.4 grams Weight of porous cup 565.4 grams Weight of mercury 408.6 grams Inner Sol., volume 450 cc spgr 1.3824 Outer Sol., volume 2000 cc spgr 1.1023 Surface of carbon 141.99 sq. inches Surface of zinc 188.49 sq. inches DATA NO. 2. ELECTRICAL PROPERTIES. Time E. M. F. P. D. C. Int. Res. Watts Int. t Ext. t R’m. t 9:40' - 1.8435 1.2667 9.252 .06532 11.61 6.00 6.00 7.50 10:40 1.7650' 1.1814 8.662 .06982 9.89 8.00 8.00 7.00 11:40 1.7646' 1.1808 8.2170 .07112 9.68 9.00 8.50 ' 5.50 12:40 _ 1.7444 1.1502 7.973 .07447 9.17 9.00 8.50 4.50 13:40 _ _ _ 1.7412. 1.1345 ■ 7.752 .07820 8.76' 9.50' 8.50 5.75 14:40 1.7385 1.1336 7.724 .09100 8.72 9.50 9.00 5.00 15:40 — ■ 1.7323 1.0'753 7.144 .09169 7.64 10.00 9.00 5.00 16:40 1.7205 1.12187 7.404 .09616 8.28 11.00 9.50 4.75 17:40 _ 1.7200 1.0511 6.951 .10'520i 7.29 10.25 9.00 4.50 18:40 ____ 1.7110 1.0242 6.621 .1099 6.75 9.50 8.00 4.00 19:40 1.7158 .9923 6.578 .1076 6.52 11.00 11.80 7.00 20:40 1.7092 .9902 6. '667 .1199 6.69 12.00 12.00 7.00 21:40 -- __ 1.7058 .9741 .6.091 .1312 . 5.93 13.20 12.00 8.00 22:40' 1.7020' .9220 5.934 .1496 5.47 14.8 13.00 9.00 23:40 1.6891 .8684 5.448 .1656 4.72 14.8 13.50 9.00 24:40 1.6640 .8247 5.0'33 .1782' 4.17 16.00 14.50 11.00 1:40 1.5977 .7950 4.70'3 .2075 3.73 17.00' 16.50 11.00 2:40 ___ - 1.5977 .7555 4.051 .2985 3.05 18.00 17.00 12.00 3:40 1.5754 .6093 2.929 .3141 2.04 19.00 18.00 14.00 4:40 1.2900 .5152 2.4695 .3148 1.26 19.00 18.00 14.00 5:40 - __ .5550' .3138 1.893 .1274 .59 19.00 18.00 16.00 6:40' .4846 .2108 1.024 .2655 .215 18.60 17.80 15.50 7:40 .4598 .798 .958 .2388 .171 18.00 17.00' 14.50 8:40 .4189 .1471 .938 .2897 .138 19.00 18.00 16.00 9:40 .. .4300 .1475 .872 .3119 .128 19.50 19.50 18.00 10:40 - .3277 .0952 .7285 .3194 .070 20.00 19.00 16.00 174 IOWA ACADEMY OP SCIENCE RECOVERY ON OPEN CIRCUIT. Time 10:^ . W;59 . 11;21 . 31:34 . il:.53 . 1*2:38 - i;3;3S . 14:54 . 10:1*3 - 17:55 . .5:30 . 11:30 . E. M. F. .3277 .3918 .4374 .7485 .7485 1.0332 1.3730 1.4133 1.4791 1.5416 1.7359 1.7410 Internal Resistance by condenser method Time ^ Int. Res. 10:57 .275 11:13 .174 11:27 .0^ 11:48 .195 13:39 .202 13:40 ^ .177 14:55 .205 16:15 .201 16:15 .235 8:30 .2605 BATTERY ON CLOSED CIRCUIT. Time E. M. F. P. D. Current '1:-^ ... .. . 1.7410 .2354 1.185 n -.^5 _ .8786 .1330 1.137 -- . . .3565 .1070 .694 17:50 >•00 . . .2730 .1455 .0351 .0730 .3010 .0021 7\'att Hours Complete Amount of work done in Joules 132.382 .476575.200 DATA NO. 3. CHEMICAL DATA. Inner sol. Outer sol. Time HjSOj Zn 1 HNO3 FE2(S0)^3 Spgr. H2SO4 Zn Spgr. .9:40 Wed 8.241 00.0 358.1 12.39 1.3824 316.09 000.0 1.1023 Fri 2.0 353.7 1.375 280.09 23.3 1.1216 15-49 — 9.6 105.0 1.1555 183.7 87.3 1.1634 9:1 'MS 21.7 37.8 1.1007 102.59 145.2 1.203 5^*40 36.3 12.6 1.0947 46.09 159.6 1.261 v-4n 2.06 30.5 4.^ 1.0947 26.39 162.1 1.280 10:40 — 1.13 31.6 .914 — 1.0951 16.99 162.9 1.284 DATA NO. 4. IOWA ACADEMY OF SCIENCE 175 DATA NO. 5. DETERMINATION OP W. Time Temp, of B. Temp, of R’m. Heat Rad. Heat in B . Total Heat W Q-4A— 10-40 6. - 8. 7.25 —1751 6063.2 43(^.2 |?i- 40—10-40 9.5-10.25 4.9 4-11150 2273.6 13423.Q 90-40—9:1 -40 12. -12.6 7.5 4-11400 1818.9 13218.9 Sr4n — 4!40 18.5-18.5 14. 4-11150 3000.0 11150.0 S- 40— 10-40 17.5-18.5 16. 4-2579 3031.6 5510.6 DATA NO. 6. DETERMINATION OP HEAT COEPPICIENT DE^DT. Time E P. D. C. T W de-^dt 9:40 1.8042 1 2240 8.907 280 00° 4309.2 -f. 000062 -f .00053 -f. 00066 -}-.00136 4-.00237 15:40 1.7264 1 0985 7.324 283 25° 13423.6 21:40 1.7075 .9821 6.379 285.60° 13218.9 11150.0 3:40 1.4327 .6072 2.699 291 50° 8:40 .4194 .1473 .905 292.00° 5610.6 DATA NO. 7. DETERMINATION OP E. M. P. Time N M E de-^-dt E. M. F. 9-49 . _ 23057. 19033 1.830 4-. 0000625 —.00053 1.8475 1.6001 1.4147 1.3863 1.0135 15:40 . 22659. 19033 1.813 91-40 20503. 19033 1.719 — .00060 3:40 ; . 21625. 19033 1.767 —.00136 7:40 ■ . _ . _ 20840. 19033 1.735 —.00237 DATA NO. 8. TOTAL EPPICIENCY. From Data No. 2 — Amount of electrical work done 476575.2 joules From Data No. 4 — Total chemical heat 205560. calories Total chemical work • 861200. joules Total efficiency 55.34 per cent 176 IOWA ACADEMY OF SCIENCE IOWA ACADEMY OF SCIENCE 177 178 IOWA ACADEMY OF SCIENCE IOWA ACADEMY OF SCIENCE 179 IOWA ACADEMY OP SCIENCE 181 EFFECT OP TEMPERATURE INEQUALITIES ON THE BALANCE. BY L. D. WELD. The topic herein presented had its origin in some work preliminary to another investigation, requiring the use of a sensitive balance operated with the greatest possible degree of precision. The balance used is by Sartorius, with 18 cm. beam and sensibility of about 2.3 scale divisions per mgr., pans empty, and so constructed that the sensibility increases slightly with moderate increase of load. The writer was studying this balance with a view to getting acquainted with its peculiarities, determining its constants and learning what degree of precision to expect of it (as should always be done with a new balance about to be used in particular work), and had taken a series of con- secutive zero readings by the oscillating pointer method with pans empty, when a marked progressive change in the readings attracted immediate attention and demanded explanation. The first readings, separated by a few moments only, were as follows; 10.56 10.56 10.41 10.45 10.37 10.33 10.32 10.27 10.26 10.09 Subsequent sets of readings, in which a fair degree of constancy had been secured, gave the probable error of a single pointer reading as less than 0.03 scale division, so that the change observed must have been real and not due simply to errors of observation. Variations of temperature were naturally looked to as the probable cause. The balance was badly located, with the right end of the case adjacent to an outside wall and the left away from' it. At this particular time, the wall was cold, and the temperature of the room was rising, so that such an effect was to be expected. But balances are frequently used in just such locations, and the magnitude of the change, amounting in only a few minutes to what would be equivalent with this balance to over 0.2 mgr. placed upon the right-hand pan, was such as not to be tolerated in precise weighing. It was thought well, therefore, to look into the matter somewhat before entering upon further work. After experimenting for a time with sensitive thermometers placed inside the case, the writer prepared a thermo-electric arrangement of ten pairs of elements, which was suspended immediately behind the beam with the two sets of junctions in juxtaposition with the two end knife-edges. This apparatus was connected with a sensitive D’Arsonval galvanometer of the wall type, which gave a deflection of twenty scale divisions per degree centigrade, so that the temperature difference between points very near the ends of the beam could be fairly estimated to about one two-hundredth of a degree. The object of this arrangement was to study the effect of known temperature inequalities in the 182 IOWA ACADEMY OP SCIENCE case upon the zero readings of the balance. One set of results must suffice here. In these, the conditions were in a measure controlled by having an eleqtrie light mounted outside the case at the left end, and turning it on and off at will. The accompanying figure best illustrates the results, which are tabulated below. Time P. M. 4:10 4:17 4:20 4:23 4:20 4:34 4:30 4:37 4:39 4:42 4:45 4:48 4:52 4: 54 4:58 5:03 5:05 5:07 5:10 5:12 5:17 5:19 5:21 Galv. Read, j Pointer Read. Remarks 2.9 15.1 16.9 17.9 11.0 15.0 16.8 18.0 19.0 19.5 20.1 20.5 20.9 11.0 5.3 4.9 4.3 4.1 10.12 10.47 10.55 10.69 10.60 10.30 9.97 9.84 10.04 10.21 10.30 10.35 10.32 10.29 10.20 9.84 9.33 9.24 9.01 9.01 Liglit off Light on Light on Light on Light off Light off Light off Light on Light on Light on Light on Light on Light on Light on Light on Light off Light off Light off Light off Light off Light off Light off Light off An examination of these curves suggests several things. Note the remark- able promptness of the pointer reading effect when the light is turned on. The second drop in the pointer reading precedes the drop in temperature difference, and is gradual instead of sudden, showing that it is due partly to other causes. This does not occur in the first and shorter exposure to radia- tion. No doubt the other causes operating to bring down the pointer reading are the equalization of temperature in the beam by conduction and the gradual growth of air currents in the case by contact with the warm glass on the left side. The same thing is noticed in the rise of the pointer reading at the end of the series, while the temperature difference is still decreasing. It is to be noted that the whole range of temperature difference is less than one degree. It is evident that air currents in the case, set up by difference of tempera- ture at the two ends, have an effect opposite to that of expansion in the beam. For. the current is downward at the cooler end, bearing down on the pan; while the corresponding arm is the shorter, which tends to raise the pan. It is difficult to say how much the effect of expansion in the beam may be thus modified by the air currents; but it is likely that with broad pans the modifica- tion may be considerable, providing the air currents have had sufficient time to get fairly started. The statement is made in some laboratory manuals that the difference in length between the two arms of a first-class balance when in adjustment will be found negligible for all but the most precise weighing, for which latter pur- pose the interchange of object and weights is recommended. This is perhaps quite true, providing the beam is at a uniform temperature; but the experi- ments herein described show how marked may be the effect of even slight temperature inequalities. Moreover, if such inequalities exist, unless they can IOWA ACADEMY OP SCIENCE 183 be kept constant throughout the various operations of the double weighing, with the opening and closing of the case that are necessary in any balance not provided with special reversing apparatus, the interchange method does not remedy the difficulty. The writer made two double weighings of the same object by the interpola- tion method, using the same individual weights in both cases, but under differ- ent temperature conditions. The first set was made on a warm day, the room being considerably colder than outside; while the second set was made on a cool day, the room being steam heated. The balance had not been adjusted as to arm ratio since its arrival from the makers; and the right arm was still toward the outside wall. The results were as follows: FIKST SET. Object on left pan 19.23112 grams Object on right pan 19.23219 grams SECOND SET. Object on left pan 19.23148 grams Object on right pan 19.23213 grams The right arm is obviously the longer in both cases. But if the mean of the first set be taken, it will be found that the residual or departure of each weighing from it is 0.00052, while for the second set the residual is only 0.00032. The explanation of this is, that in the first case the right arm was warmer than the left, thus adding to the inequality, while in the second, it was cooler, subtracting from it. The difference in temperature at the ends of the beam could not have been in either case more than one or two-tenths of a degree, as indicated by the galvanometer. The beam of the balance here used is of phosphor-bronze, with a centigrade coefficient of expansion," according to the makers, of 0.0000181. A simple calcu- lation, using this figure and the known constants of the balance, shows that a uniform temperature gradient of one degree from one end of the beam to the other, barring air currents, would produce an anomalous deflection of about 1:8 scale divisions, corresponding to well toward a milligram. The thermo- electric apparatus, when used under the best conditions obtainable in the winter with the balance situated as it was, though carefully screened and blanketed, showed temperature gradients of nearly one-fourth of one degree, and much greater ones when no special precautions were taken. The varia- tions observed are therefore not at all surprising. In conclusion, it may be suggested that sufficient care is seldom taken in conducting balance work to secure freedom from the disturbing influences of temperature gradients, direct radiation and accidental air currents. For suc- cessful work, the balance should be centrally located in a quiet, thermostatic room, on a pier if possible, and carefully screened from radiations from heating apparatus, artificial lights and sunlit windows. It is well to blanket the case, and the illumination should come from the front, not from the side. Unless such precautions are taken, it is doubtful if the great precision often claimed for weighing methods can actually be realized. Further, it will bo found a source of satisfaction, to anyone endeavoring to get the best results from weighings, to install within the case, as described, a thermo-electric series of simple design, which will give warning of the presence of temperature inequal- 184 IOWA ACADEMY OP SCIENCE ities, and thus indicate when the best conditions exist. Such a thermopile may be easily made in any laboratory shop from iron and copper wires mounted on an ebonite or wooden frame, and can he located so as to he used during weighing without being in the way. Cor'iTes/Doncling Ternfaer'^Ture Dijji IOWA ACADEMY OP SCIENCE 185 EVAPORATION FROM FREE WATER SURFACES. BY ARTHUR G. SMITH. The very extensive work being done by the United States Reclamation Service in the storing and preserving of the waters of the arid and sub-arid regions of this country, has brought prominently before irrigation engineers the ques- tion of the amount of evaporation taking place at different places and under various external conditions. Taking for example the annual evaporation from a reservoir in Arizona, as amounting to six feet, and supposing the amount of water needed for satisfac- tory irrigation as two feet then 'we see that in a reservoir like the Roosevelt reservoir with a surface of 16,000 acres area, it means that the efficiency of the reservoir is reduced by nearly 50,000 acres. A loss that is very considerable in comparison with the total capacity of the reservoir. If we suppose the value of the irrigation to an acre of ground to be say five dollars a year, then this evaporation means a loss of a quarter of a million dollars a year to the arid region surrounding this particular reservoir. While the amount of evaporation from the water surface is a matter of both scientific and economic importance in the arid west, it is also of considerable interest in the humid regions of the middle west. During the summer of 1906 through the kindness of Mr. A. H. Horton, United States Hydrographic Engineer, an evaporation gaging station was estab- lished at Iowa City, the reader having charge of the work. It is a well known fact that the evaporation consists of two steps; first the liquid must be changed to the vapor state forming a film as it w^ere upon the water surface and then this film must be removed by the atmospheric move- ments in order that another dryer layer of air may take the place of this saturated film and take up the succeeding evaporation. The amount of evapora- tion will of course depend upon vapor pressure and this will depend upon temperature. The removal of the film of saturated air and its mixture with the upper layers of the air, depends very largely upon the wind. If we think of the wind as advancing across a considerable body of water and thus becom- ing more or less saturated with water vapor, the removal of the film will be- come less and less effective. It may then be expected that the average evapora- tion will not be so great from a large body of water as from a smaller area for the unit area. During the midsummer months the water surface is cooler than the air above and the tendency is for the cooled air in contact with the water surface to hang upon the surface sinking rather than rising unless the wind is sufficient to remove it. Later in the year, say from the middle of August on the water surface except in the middle of the day is w^armer than the air above and the air warmed by contact with the water not only takes up the water vapor but then rises from its expansion and gives place to dryer 186 IOWA ACADEMY OP SCIENCE air; thus the amount of evaporation is increased especially during the night time. In order to measure the evaporation from the surface of streams and lakes, pans are floated in them and the evaporation from these pans is measured. In order that comparisons might be made upon the relative rates of evaporation from pans similar in every respect except that one is surrounded by land and the other by water, two pans were installed. One was floated upon the river and the other imbedded in the ground upon the bank of the river; the pans were three feet square and eighteen inches deep, filled with water to within about one and one-half inches of the top. A sharp point set in the middle of the pan is just kept covered; the amount of evaporation being measured by the number of cups of water required at time of observation to just cover this point. By using a rain-gage to allow for rainfall it is possible to measure with accuracy to the one-hundredth of an inch the amount of evaporation. The surfaces of the water in the pans were adjusted morning and evening at 8 A. M. and 6 P. M.; the temperature of the water being taken both in the pan and in the river outisde. By means of a sling psychrometer the relative humid- ity was determined at seven o’clock both morning and evening. An estimate was also made of the maximum velocity of the wind in the course of the twenty-four hours. The amount of data collected, to the present time, is not sufficient to war- rant more than the noting of certain facts; one can hardly say conclusions, for conclusions resting on insufficient statistical evidence becomes nothing but weighted guesses. To note briefly some of the results obtained; The total amount of evaporation, from the river pan during the summer of 1906, was in excess of that from the land pan in the ratio of 100 to 90; during the six months from April 1st to October 31st, 1907, while reading were made, the evaporation from the land pan exceeded that from the river in the ratio of 100 to 92, and the month of April, 1908, just past, has shown an evaporation from the land pan one-fourth greater than from the river pan. While at first thought it might be expected that the evaporation from the land pan would be the greater, it should be borne in mind that the river pan, especially in the late summer and fall, has a temperature markedly above that of the land, and for this reason the rate tends to rise higher for the river pan at this time of the year. It is the reader’s opinion that on the whole the evaporation from the river pan will be found to be above that from the land pan. This is of course for a pan upon a stream as small as the Iowa river. The following table gives the evaporation from the two pans for the six months of 1907, named above and also April, 1908. Relative amounts for Land pan River pan night or day 1907 Inches Inches Land River April 2.95 2.14 57% 56% May 3.38 3.18 61 80 June 3.03 2.60 66 74 July 4.75 66 68 August 4.73 4.34 90 86 September 2.98 71 75 October 1.91 1908 April 2.40 51 71 IOWA ACADEMY OF SCIENCE 187 The following table gives the amount of precipitation for the corresponding months of the year at Iowa City. April . . . . May June July August . . September October . . 3.2 inches 4.3 inches 3.0 inches ,4.5 inches ,3.3 inches ,3.5 inches ,2.4 inches It will be seen at once that even in a humid climate like this, that the total evaporation from exposed water surfaces is quite comparable with the tota? precipitation, possibly as great. The relative evaporation during the night to that of the day is perhaps larger than might be expected. This is as has already been spoken of, due in part to the higher temperature of the water during the night than of the air in contact with it. This higher temperature is much more marked for the river than the land pan. The values found for the relative humidity at seven o’clock in the morning and evening are as follows: Relative humidity 1907 7 A. M. 7 P. M. April 86% 81% May 87 79 June 88 82 July 92 88 August 91 84 September 92 87 October 94 83 1908 April 89 79 The temperature of the water in each of the pans and of the river surface is of considerable value, giving some clue to the causes of the fluctuations in the amount of evaporation. The river temperature is also of interest as it shows the march in temperature during the summer months, in the water flowing in such a stream. The following table show^s these various tempera- tures as well as the average temperature of the air as taken from the mean of the readings made at 7 A. M. and 7 P. M. It should be noted that this mean is some five degrees lower than the mean as computed from maxima and minima readings. Land-pan River -pan River Surface Mean Temp. 1907 8 A. M. 6 P. M. 8 A. M. 6 P. M. 8 A. M. 6 P. M. April 43.0 50.0 46.3 48.5 47.3 48.2 40.1 May 51.6 61.8 57.2 59.7 57.9 59.7 54.4 June 66.7 73.0 69.0 71.4 69.0 71.8 65.0 July 74.3 81.0 75.5 78.8 77.3 78.8 72.0 August 72.0 78.5 74.3 76.5 75.1 77.0 69.0 September 61.0 68.5 68.2 69.7 69.1 70.0 61.0 October _ _ 50.0 55.5 52.7 55.5 53.5 55.7 47.0 188 IOWA ACADEMY OF SCIENCE A number of theoretical formulae have been proposed for the computation of evaporation from freely exposed water surfaces the general form of which is the simple one given by Dalton E = A (a-b) (1 + ck) where the argufnents A,c,K are the temperature of the water surface, the dew point of the atmosphere and the movement of the wind, a and b being the dry and wet bulbs. Carpenter from Ft. Collins .in 1887 proposed the following, which is of this form; E,inch-day=0.3868 (e^— e j, ) (l+0.0025w), where w is the wind movement per day in kilometers. The constants suggested here apply satisfactorily only to local conditions and are not general. The author hopes in another year to offer a formula that shall be satisfac- tory for the Iowa river conditions but is not prepared to do so at the present time. IOWA ACADEMY OP SCIENCE 189 THE FIFTH AND SEVENTH CRANIAL NERVES IN PLETHODON GLUTINOSUS. BY H. W. NORRIS. Thinking that possibly some of the conditions described by Dodds (1906) in the cranial nerves of Plethodon glutinous might throw some light upon the homologies of the ramus maxillaris V in the urbdele amphibians the writer was led to work out carefully the distribution of the fifth cranial nerve and its branches, together with those of the seventh nerve, in the same species. The material, small adults 35mm. long, was fixed in Vom Rath’s picro-acetic- osmic-platinic mixture, infiltrated and sectioned in celloidin, and studied en- tirely from cross-sections. Although the differential staining was not as thor- ough as the writer has usually obtained by this method with amphibian material, yet except for very minute branches its precision is reliable. According to Dodds there spring from the gasserian ganglion of Plethodon glutinosus three nerves: rr. mandibularis, maxillaris and ophthalmicus (pro- fundus). The rr. mandibularis and maxillaris arise together and pass out by a common foramen. I find that three nerves arise from the dorso-lateral border of the ganglion, one of which is the r. mand. Dorsal to the latter there emerge two others that evidently represent collectively the r. max. of Dodds. Accord- ing to the latter the r. max. branch “passes off laterally and curves forward in twm parts. One branch (infraorbital) breaks up back of the eye-ball, and the other (maxillary) passes forward a little above the maxilla.” Of these two nerves that I find leaving the gasserian ganglion dorsal to the r. mand. the dorsal one is distributed to the skin dorsal and posterior to the eyeball. The more ventral passes anteriorly until it comes in contact with the posterior border of the eyeball, where it divides into about five branches, of which two are distributed to the skin dorsal and anterior to the eye, while the other branches pass ventrally and are distributed to the skin ventral and anterior to the eye and dorsal to the mouth. Dodds is doubtless correct in interpreting these two branches as the r. maxillaris V. That in many cases they arise from the ganglion as a single nerve, as described by him, is probable. Dodds states that “the mandibular passes off laterally and soon curves ven- tralward to the maxilla, where it breaks up into three branches. Two of these remain in the upper jaw and pass forward well into the snout, one just external to, and the other just internal to the maxilla. * * * These two branches may possibly represent a part of the maxillary ramus. The third branch, about equal in size to the other two combined, passes ventralward into the lower jaw.” Such a distribution of the branches of the mandibular ramus as des- cribed by Dodds would be very unusual. I cannot agree with him as to the facts in the case. The r. mandibularis passes ventro-laterally from the gasserian ganglion and after giving off motor branches to the temporal, pterygoid and masseter muscles and a medium sized sensory branch to the skin, divides just 190 IOWA ACADEMY OF SCIENCE dorsal to the mandible into three branches. One of these passes straight ven- trally through the mandible between Meckel’s cartilage and the dentary bone to be distributed to the intermandibular (m. mylohyoideus anterior) muscles anterior and posterior, and to the skin of -the ventral surface of the head ex- ternal to these muscles. The distribution of this branch is that which usually obtains in the Urodela. Miss Bowers (1900) designates it in Spelerpes as md. interims V. A second branch runs anteriorly at the lateral border of the mandible supplying the skin of the side of the lower jaw. This branch also has nothing unusual in its distribution. It has been described in Amblystoma (Coghill, 1902), Spelerpes (Bowers) and Amphiuma (Norris, 1908) and evidently is a constant feature in urodele anatomy. Miss Bowers terms it r. md. ex- ternus V. The third branch runs anteriorly along the dorsal border of Meckel’s cartilage, then gradually shifts medially and ventrally between the cartilage and the angulo-splenial bone and fuses with a branch of the r. alveolaris VII. This combined nerve of general cutaneous and communis fibers runs anteriorly, presumably to supply the teeth and lateral floor of the mouth. This third branch has no peculiarities, and its anastomosis with the alveolaris has been described in Amblystoma and Amphiuma. Miss Bowers does not describe it in Spelerpes, but my own preparations of Spelerpes show it very distinctly, and that the anastomosis with the alveolaris undoubtedly occurs. None of these three branches of the r. mandibularis remain in the upper jaw, nor can I find any branches such as Dodds describes in the upper jaw. Coghill describes in Amblystoma an anastomosis between the motor portion of the r. mand. supplying the intermandibular muscles and the motor part of the r. jugularis VII supplying the interhyoid muscle. A similar anastomosis occurs in Plethodon. Of the ramus ophthalmicus profundus V Dodds says: ‘Tt soon divides into two branches. One of these extends dorso-lateral and breaks up in the muscles in front of the eye.” Although this is not a positive statement that this dorsal branch is motor, yet such an inference may be drawn. There are no muscles in Plethodon anterior to the eyeball unless we except the superior and inferior oblique muscles of the eyeball itself. Furthermore, this dorsal branch is ex- clusively general cutaneous in composition and is distributed to the upper eye- lid and the skin of the dorsal side of the head mesial and anterior to the eye. Examination of the published figures of the cranial nerves of Amblystoma, Spelerpes and Amphiuma shows that similar branches are found in these forms. Dodds correctly describes the three terminal divisions of the main portion of the r. oph. prof,: a mesial, a lateral and a ventral branch, the latter anastomos- ing with the r. palatinus VII. The condition seems to be similar to that in Amblystoma and Spelerpes. Of the exact nature of the anastomosis with the R. pal. VII the material studied does not give exact information. Apparently it differs from that described in Amblystoma and Amphiuma. In the material studied the lateral line system had disappeared. Hence the VII-VIII complex is much simplified over that of the larval stage. The VII-VIII nerves arise from the brain by three groups of rootlets: a dorsal communis, a middle auditory and a ventral motor group. From the common ganglion of the VII-VIII nerves an anterior auditory vestibular branch passes to the utriculus and the anterior and horizontal semicircular canals of the ear. From the posterior part of the ganglion a number of auditory branches pass to the sacculus, lagena, etc. Dodds says that a single small twig supplies this portion of the ear. From IOWA ACADEMY OF SCIENCE 191 the antero-lateral portion of the ganglion the fibers of the facial nerve emerge in two parts: an anterior r. palatinus and a lateral r. hyomandibularis. The palatine branch passes anteriorly to its anastomosis with the r. ophthalmicus profundus already mentioned. A Jacobson’s commissure between the IX nerve and the r. pal. VII evidently exists, but its entire course was not traced. The main portion of the facial nerve, truncus hyomandibularis, passes posteriorly, laterally and ventrally from the ganglion. It soon gives off a r. alveolaris (not noticed by Dodds) that passes antero-ventrally to supply the lateral floor of the mouth. Its anastomosis with the r. mandibularis V has been described. Near the place where the r. alveolaris leaves the hyomandibular trunk the latter receives the ramus communicans from the IX nerve. Most of the fibers of the r. communicans enter the r. alveolaris and are evidently communis. Of the exact composition of the r. communicans no reliable information was gained, but apparently general cutaneous fibers are contained in it. The con- dition seems to be very much like that described by Coghill in Amblystoma. After giving off the r. alveolaris the hyomandibular trunk supplies the depressor mandibulae, sphincter colli and interhyoideus muscles and apparently sends general cutaneous fibers to the skin overlying these muscles. A comparison of a plotting of the fifth and seventh cranial nerves of an adult Plethodon with that of a larval Spelerpes (as given by Miss Bowers), shows that after omitting the lateral line system of the latter the resemblances are very close, so close as to make evident an almost identical arrangement in the two. It would appear that Dodds is completely in error in supposing that there are any anomalies in the composition and distribution of the fifth cranial nerve in Plethodon gliitinosus. LITERATURE CITED. Bowers, Mary a. 1900. The peripheral distribution of the cranial nerves of Spelerpes bilineatus. Proc. Amer. Acad. Arts and Sci., vol. 36. Coghill., G'. E. 1902. The cranial nerves of Amlystoma tigrinum. Jour. Comp. Neurol., vol. 12. Dodds, G. S. 1906. The cranial nerves of one of the salamanders (Plethedon glutinosus). Univ. of Colorado Studies, vol. 3, no. 2. Norris, H. W. 1908. The cranial nerves of Amphiuma means. Jour. Comp. Neurol, and Pscyh., vol. 18, no. 6. IOWA ACADEMY OF SCIENCE 193 THE RELATIVE FREQUENCY OF ARTERIO SCLEROSIS OF THE VARIOUS ARTERIES. BY W. E. SANDEES. The present paper is a preliminary report of one phase of a series of arterio sclerotic cases which the author studied during the summer of 1908 while engaged in pathological studies in Berlin and Munich. A brief autopsy report was taken of each case, especial attention being given to the condition of the heart and kidneys. The macroscopic appearance of the vessels were noted at the autopsy and specimens taken for further microscopic study. The vessels selected were the arch of the Aorta, the Pulmonary, the Coronaries, the Splenic, the Renals, the Internal Carotid, just below the circle of Willis, or pre fossi sylvii, and occasion- ally various other arteries. The material included only selected cases from some 300 post-mortems with a view of elimina.ting syphilitic endo and mesarteritis and including only early cases of the so-called senile artero sclerosis, the primary object being to determ- ine the nature and location of the initial process and if the same be of a circum- scribed or diffuse character. The critical phases of the subject I shall not dis- cuss in this paper but shall reserve it for a later contribution. The specimens v/ere fixed in 2 per cent Formol cut with the freezing micro- tome and stained with Hsematoxoylin and Sudan iii, for degenerative changes, and Carmine and Weigert’s elastic stain for the changes in the elastic elements. The following is an epitome of twenty cases. In describing the extent of the process I have used the terms minimal, moderate and pronounced. It must be understood, however, that these terms are used only in a relative sense as the cases Trere most all as I have, previously stated in the initial or early stage of the disease. Case I. Male, 51. Died from carcinoma of the cesophigus. The thoracic aorta was free, the abdominal aorta minimal sclerosis. The left coronary and splenic minimal, the right renal moderate and the left renal and the right femoral pronounced changes. Case II. Male, 56. Died from Addison’s disease. Thoracic and abdominal pronounced, both carotids and both coronaries moderate, splenic, both renals and the coeliac axis minimal and the basalar and cerebrals free. Case III. Male, 46. Died from purulent meningitis. The thoracic and abdominal aorta, the subclavian, both carotids, the splenic and both renals minimal, the left coronary pronounced, the right coronary and cerebrals free. Case IV. Male, 47. Died from a myxo' sarcomatous tumor of the medias- tinum. 13 194 IOWA ACADEMY OP SCIENCE Thoracic and abdominal aorta, splenic and left renal minimal, left and right coronary and right renal moderately effected. Case V. Male, 76. Acute infection, likely influenza. Thoracic and upper abdominal and right coronary moderate, descending branch of the left coronary pronouncedly, splenic, left renal and internal caro- tid negative, pulmonary minimal. Case VI. Male, 72. Died from cerebral apoplexy. This case was rather ad- vanced but was studied with a view of noting the condition of the vessels in general in relation to the apoplectic insult. Pronounced sclerosis of the aortic arch, atheromatous ulcer of the abdominal aorta, splenic and coronaries pronounced with calcification of the latter, right renal moderate, left renal, pre fossi sylvian and pulmonary minimal. The sub- clavial and common carotid pronounced, the hasalar and vertebral were nega- tive notwithstanding the cerebral hemorrage. Case VII. Male, 39. Died from pernicious anaemia. The aortic bulb at the origin of the left coronary as well as the latter itself show minimal localized sclerotic patches, the left common carotid moderate, coeliac, both renals and the splenic minimal. The right coronary and prefossi sylvii were not studied. Case VIII. Male, 47. This was a medico legal .case, the man dying sud- denly after falling on the sidewalk. Examination revealed pronounced scler- osis and some atheroma of the aortic arch and pronounced sclerotic stenosis of the origin of the left cornary. The right coronary was minimally effected. The other vessels were free. The diagnosis of angina pectoris was established. Case IX. Male, 68. Died from carcinoma of the ampulla of the rectum. The aortic arch showed minimal sclerosis, the abdominal aorta moderate sclerosis with atheromitous ulcers about the original of the renals. The cere- bral vessels were not examined but the other vessels revealed no macroscopic changes. Case X. Male, 34. Died from peritonitis, caused from a perforating carci- noma of the stomach. The arch of the aorta showed minimal circumscribed slightly elevated yel- lowish sclerotic patches. The other vessels were free. Case XI. Male, 40. Died from typhoid fever. The aorta and the pulmonalis showed moderate circumscribed slightly ele- vated yellowish sclerotic patches. The other vessels are not diseased. This case is of interest because of the infection which existed, some authorities claiming infections, particularly typhoid, as an important etiological factor in arterlo sclerosis. Case XII. Male, 33. Died from heart disease. This case is of special in- terest because the sclerosis was practically limited to the pulmonary arteries while the systemic vessels were free. I have reported the case elsewhere. (Arch, of Internal Med., April 15, 1909.) The aortic arch showed minimal sclerosis but the pulmunary, especially the medium and smaller branches revealed a pronounced diffuse sclerotic thickening limited to the intima. Case XIII. Male, about 50. Died from cerebral hemorrage. The coronaries, the basilar, the pre fossi sylvii and the cerebral all pro- nouncedly affected. The aorta, the renals and the splenic only minimal IOWA ACADEMY OF SCIENCE 195 changes. This man also had a gastric ulcer which very possibly was induced by sclerosis of the gastric vessels. Case XIV. Male, 40. Died from tubercular meningitis and pulmonary tuber- culosis. The aorta from the arch to the iliacs showed moderate sclerotic patches. The pulmonary minimal, also the coronaries, the inferior thyroid, the pre fossi sylvii and the right common iliac moderately affected. Case XV. Male, 31. Diagnosis cardiac insufficiency. Right side pleurisy. Aortic arch pronounced plate like sclerotic elevations. Thoracic aorta mini- mal pessary like elevations around the orifices of some of the intercostals. The coronaries, the renals were very slightly affected, while the splenic and pre fossi sylvii were negative. Case XVI. Male, 54. Died from heart disease, odcema of the extremities marked. Aorta and both renals moderate, coronaries minimally affected. This may have been syphilitic. Case XVII. Male, 62. Died of sepsis from a carbuncle. Had also chronic interstitial nephritis. Aorta pronouncedly sclerotic with atheromatous degeneration in the abdo- minal portion. Coronaries, splenic and renals moderately affected, arteria pre fossi sylvii very slightly. Case XVIII. Female, 48. Died from heart disease, old mitral stenosis and acute endocarditis. Aorta minimally, stem of pulmonary moderately, while the medial and the smaller sized pulmonary vessels are pronouncedly sclerotic. The splenic, re- nals and vertebral show only minimal sclerosis. Case XIX. Female, 60. Died from some acute infection. Pronounced sclerosis with some atheroma of the aorta, both coronaries and both renals moderately and the splenic and pre fossi sylvii only slightly af- fected. ' Case XX. Male, 40. Died from carcinoma of the pancreas. The aortis arch, moderate circumscript patches near the origin of the caro- tids and coronaries. Abdominal portion atheromatous changes some in the ulcerative stage, the coronaries themselves only minimal sclerosis. Renals coeliac and pulmonalis free. These twenty cases showed four between 30 and 40, seven between 40 and 50, four between 50 and 60, three between 60 and 70, and two between 70 and 80. The youngest was 31 and the oldest 76. Chart I. * = not studied; o = negative; i, ii, iii = minimal, moderate and pronounced sclerosis. Of the twenty cases studied, nineteen or 95 per cent revealed sclerosis of the aortio arch; fourteen or 70 per cent of the thoracic; fifteen or 75 per cent of the abdominal; fifteen or 75 per cent of the left coronary; twelve of the eighteen right coronaries, or 60 per cent; thirteen of the left renals, or 65 per cent; fif- teen or 75 per cent of the right renals; twelve out of nineteen, or 57 per cent, of the splenics; five of the thirteen, or 37 per cent, of the pre fossi sylvii. In general the degree of the process is in accord with its frequency. Without entering into detail I may state that the result of my study has demonstrated conclusively that so far as histological evidence is concerned the process is essentially limited to the intima being of the hyperplastic connec- 7 196 IOWA ACADEMY OF SCIENCE live tissue type. The character of the rather superficial circumscribed yellow- ish elevations so commonly observed in infectious cases, correspond very well with the changes produced experimentally by treating animals with such sub- stances as adrenalin, nicotine, bacteria and their toxins, et cetera, and I am by no means convinced that they bear any relationship to the type of sclerosis here discussed. The degenerative changes which occur in advanced cases are invariably of a secondary character and almost always begin in the deeper layer of the intima. One of the early changes observed in the smaller vessels is a fission or lamellation of the elastica interna, the interstices becoming filled with con- nective tissue cells. IOWA ACADEMY OP SCIENCE 197 THE SUMMER-RESIDENT BIRDS OP POLK COUNTY, IOWA— A GUIDE TO LOCAL STUDY. BY LESTEE P. FAGEN. This paper consists of notes on the more common summer-resident birds of Polk county, Iowa, Its purpose is not to give an exhaustive treatment of the subject, but merely to include those birds which the true, faithful student can expect to find nesting in this county every summer. This is not in any way a key to the identification of the birds when found. There are many books giving reliable color keys for that purpose, perhaps the best one of which is Chapman’s “Birds of Eastern North America.” The true purpose of the paper is two-fold. Pirst, to give the reader a glimpse of the possibilities of profitable, extensive study which may be prosecuted by one desiring to become acquainted with the birds of this county. Second, to furnish a guide to the local study of our Polk county summer birds. I have selected one hundred birds, all but a very few of which are now common, during the nesting season, in this section of the state. I have drawn upon my twelve or fourteen years of almost continual observation to localize for this county what is given in a general way by most writers on the subject of birds. Polk county, Iowa, is an exceptionally well favored section for the study of birds, for in it we find everything of environment from the open stretches of prairie to the deep, quiet woods, from the high, dry uplands to the low- land, riverbottom marshes, everything from the fiat, level prairie to the rugged, wooded hills; and streams of nearly all sizes with occasionally large ponds and small lakes. Each locality attracts its different types of birds, and until very recently Polk county had almost anything in the environment asked for except mountains and salt water. The past five years have made some differ- ences, however, which have changed somewhat the personnel of our feathered citizenship, for the tiling out of our bigger marshes, the cutting down and settling up of our heavier wooded tracts have wrought changes which make it more difficult to find the birds whose haunts are the deep woods or the big swamps. The unrestrained killing instinct of man and the barbarous taste of women have also caused some of our more common birds to become little more than memories. Some of these birds once common here but for one reason or another not so any longer, I have included in this paper, stating in each case the cause of its disappearance. This work contains then all of our common summer-residents with the local hints as to where they may be found by one wishing to use this paper as a local guide. I feel sure that it will prove in all respects reliable and trust worthy for this locality. A word of caution, however, will not be out of place at this time for the one who is to begin this personal study of birds. To such a one let me say, — do 198 IOWA ACADEMY OF SCIENCE not expect to find all of these birds in one week or even in one season. When hunting birds, do not wear fiashy, startling colored clothes. Do not approach the bird you are seeking to identify in a direct line nor in a stealthy mg^nner. After identifying a bird, do not rush off at once to find another but watch the one that you have found and become acquainted with him, — his manner of feeding, his call notes and songs, his peculiarity of flight, and if possible, his nesting place. Learn not to be discouraged or surprised if, some days, you arrive in a locality that should be full of birds and fail to find any. That is one of the most valuable assets in your search for birds, though by no means necessary, is a good field glass or a pair of opera-glasses. With this much for suggestions and instructions, I shall now proceed with the individual consideration of the birds, taking them up in their order of families. ORDER PASSERES: PERCHING BIRDS. American RoHn. By far the best known of our native birds, the robin heads our list. From early March until the snow begins. to fly the following winter, his cheery song in its simple melody resounds throughout city streets and around our farmhouses and orchards. His nest, a course structure of hay and twigs plastered outside and in with mud and lined with dried grass, is easily found and recognized. In it are laid four to six eggs of a peculiar shade of greenish blue. The Wood Thrush. In some localities, this second of the silver tongued family is known almost as well as the robin, but not so in Polk county. From early May till late in August, in the heavier wooded hills, his voice may be frequently heard in its ringing melody. Seen at close range, his beauty is a match for his rolling, vibrating song. His nest and eggs are much like that of his cousin, the robin. The wood thrush stays here until in October, when he leaves to return about the first of May. Wilson's Thrush, Yeery. The veery is the most slender and graceful of the thrushes. Its first arrival in early May will be the best time to see it, for when it retreats into the woods to build its nest, all disappears except the voice, that ringing “echo-song” that causes one to listen in glad bewilderment, then search, ofttimes in vain, to find the singer. His nest is like the wood thrush’s, but it lacks the mud. Its eggs, its haunts and winter home are so like those of the wood thrush that a separate description is not needed. Blue Bird. The baby blue bird first sees the light in the inside of an aban- doned woodpecker’s hole, a bird house, or decayed knot hole, and learns to fly within a few short weeks. Late in October he leaves the state of his birth to take up winter quarters in the Gulf states and Cuba, only to return again in early March to vie with the robin for first honors in reporting coming spring. His song is mellow and assuring. Heard at a distance it has a purling quality and through it all runs a note of sadness that blends in rare harmony with the cheery, rolling notes of the robin and the wood thrush. Chickadee. This jolly sociable little fellow is a yearly resident with us and may be found wherever there are trees or bushes. He builds a tiny nest of feathers and down in a hole in a stump or tree a short distance from the ground IOWA ACADEMY OP SCIENCE 199 but well concealed. His song has a care free merry ring to it which goes well with the character of the singer. 'White-Breasted Nut-Hatch. Though excelled as contortionists by the parrots, the nut-hatches stand in a class by themselves, — our recognized bird acrobats, running head downward down a tree on the under side of a limb, using only their feet as means of support and never their tails as do the woodpeckers and creepers. This white-breasted cousin of the chickadee reminds one often of our little black-capped friend, staying with us all the year and showing many of the jolly, sociable characteristics of his irrepressible cousin. His nest is much like that of the chickadee except that the hole which he uses is excavated by the nut-hatch himself, and is not a natural cavity or an old excavation. In winter the nut-hatches are often found with flocks of titmice and kinglets, and are of our most beneflcial birds, destroying thousands of scale insects and eggs of larger ones. Red-Breasted Nut-Hatch. What has been said of the preceding species can be said of this except that as a rule, in this part of Iowa, the red-breasted one is^much shyer and more retiring than the white-breasted. The red-breasted species is really rather rare in Polk county the past few years, though in some parts of the state it is more frequently found than the white-breasted. Gat Bird. The cat-bird, one of the tamest of our native birds, is a true mocker, but he also has a song of his own that is full of rolling melody, only slightly inferior to that of the brown thrasher. Prom early May until October or November he may be found in and about the gardens and orchards, stealing fruit sometimes, but always eating insects. His nest is built in a bush or small tree, and looks much like the thrush’s but lacks the mud. The cat-bird winters in the southern states and Central America. Brown Thrasher. Prom the time of his arrival about the last week of April till -the last week of June, the thrasher is the most enthusiastic songster we have. Por the first week or two, there is a continuous flow of almost uninter- rupted song. Then begins the nesting period. The music does not stop, how- ever, but continues at intervals every day until the last of June. Though not quite so common or sociable as the cat-bird, it is a well known bird in the spring, seen frequently at midday on the topmost twig of a tall tree, pouring out his soul to the great wmrld about. Its habits, though confined more to the light wmods, are very much like the cat-bird’s. Its stay here ends early in October, when it leaves for winter quarters in the southern states. House Wren. These busy little bodies, the children’s favorites, arrive usually about April 15th and stay until the first week in October, during which time three nests are built and three broods raised. The nest is built in corners about houses, barns and outbuildings, in old shoes, mittens, cans, boxes, and indeed anything that can be made cozy when nearly filled with sticks and straw. The wren, being so small, hardly suggests its relationship to the cat-bird and brown thrasher except by his busy habits and the joyous manner of his singing all the day through. The house wren’s winters are spent in the southern states and Mexico. Long-Billed Marsh Wren. A bird of moist meadows and reedy swamps, we find this fellow nearly as jolly and fearless as the house wren itself. He builds his nest and lives in places not easily accessible by man. 200 IOWA ACADEMY OF SCIENCE One nest is built for the rearing of the brood, and while the eggs are being laid and hatched, the male builds from four to seven dummy nests near the real one in more conspicuous places to delude the molester. Their stay here is from early May until September. Short-Mlled Marsh Wren. The short-billed marsh wren is much rarer than the long-billed species, erratic in its habits, some years being found in several marshes about Des Moines, and other years in none of them. Their habits and all are identical with the long-billed except that they are shyer. Black and White Warhler. This alert little fellow is only spasmodically common in Polk county, some years being very rare indeed. His arrival from Central America is about May first and his departure for the south again is about September first. His habits are so like those of the downy woodpecker, as he rambles around over the trunks of the trees in search of larvae, that you may easily mistake him for the downy. His nest is hidden very adroitly in a stump or on the ground, and is one of the most difficult to find. Yellow Warhler. From their winter home in northern South America, these little fellows arrive about May first to stay until September. They are very sociable and confiding, feeling as much at home in the trees by the house as in seclusion. This is the little warbler who always baffles the lazy cowbird, when her nest is victimized, by building a second story over the unwelcome egg, leaving it in the one below. The yellow warblers, like ail other warblers, feed entirely on insects, and are of invaluable aid to the farmer and fruit raiser. Chestnut-Sided War'bler. A shy little bird, of a retiring disposition, the chestnut-sided v/arbler is not well knov\^n in Iowa. It is not found here in great numbers, but in the spring may be found often in company with the redstarts feeding industriously on the insects in the orchards and gardens. When the nesting season arrives, they retire to the seclusion of the woods and are very seldom seen or heard. From May to September is their season in central Iowa. Prairie War'bler. The prairie warbler is probably the smallest warbler that nests here, and has a quaint and curious song, for which it is most noted. Found usually in shrub dotted pastures or brushy light woods it builds an elaborate and beautiful nest in a small tree or low bush. Ovenhird: Golden Crowned Thrush. To come to know the Ovenbird is one of the greatest feats of the nature student, for while not rare in Polk county it is one of the most shy birds we have. A bird of the deep quiet woods, his wild defiant call of “Teacher, teacher, teacher,” is in keeping with his life of untamed freedom. His love song, melodious beyond description, is seldom heard by human ear, while his nest, that little hut of dead leaves and grasses with the door at the side, though widely famed, is seldom found. His season with us is from May to October. Maryland Yellow-Throat. One of the merriest, most bewitching of our ground warblers, the Maryland yellow-throat can be found in old brushy pastures or near willow-edged swamps at nearly any time during the summer. From his arrival in May until his departure for the Gulf states, in Septem- ber, his song may be heard and his happy, roguish face seen by the earnest seeker. His nest is large and deep, sometimes partly roofed over, made of broad grasses and put either on the ground or in a bushy tangle. IOWA ACADEMY OP SCIENCE 201 Yellow-Breasted Chat. The most distracting, uncertain bird in the whole tribe, the yellow-breasted chat seems to take almost fiendish delight in the be- wilderment caused bird lovers by his mocking, ventriloquous voice. The chat can imitate almost any bird as well as man’s whistle and voice. With us from May first to September first. The chat may be found usually along country roads, in small groves and about gardens and orchards. The nest is built of bark and twigs, lined with soft grasses and placed in briary, inaccessible bushes near the ground. American Redstart. This little, self-important warbler reminds one of a miniature bantam rooster when seen strutting about on the ground the first day of his arrival from the south in early May. When the nesting time comes, he retires to the quiet of the woods. Kirk- wood Glen, a few years ago, was a favorite resort for the redstart, but now we must go farther, to Walnut Creek or Pour Mile Creek or the wooded tracts off of Beaver Ave. and North Thirtieth Street. The nest is a carefully made structure of moss fibres and horsehair, set in a forked branch about twenty feet from the ground. Like many other warblers, the redstart leaves for Mexico and South America in September. Red-Eyed Vireo. This bird that always builds into its nest some cobwebs, and usually some scraps of hornets’ nests, is one whose song is seldom noticed until late in May, but from then on through July it is a constant singer. In our groves and lightly wooded tracts, the red-eyed vireos nest in comparative abundance throughout Polk county. The nest is one of the most beautiful and perfect we have. A cup-like, pensile nest in a slender fork of maple, oak or apple tree about eight or nine feet from the ground, it is a most remarkable piece of workmanship, composed of fibers, string, cobwebs, scraps of paper and bits of hornets’ nests, all woven in to form a firm, durable structure of great beauty and daintiness. White-Eyed Vireo. The general habits of the white-eyed vireo resemble those of the red-eyed species except that it is less common, comes later in April or early May, and builds its nest in lower bushes or vines. It frequents the gardens and orchards more than the red-eyed, and is bolder, being quite a scold at times when disturbed. Warhling Vireo. The warbling vireo resembles very closely the red-eyed in all its habits. Its nest, however, is usually placed at a height of twenty or thirty feet and contains some moss as a rule. Its song is much more beautiful than the red-eyed, though even he has much of sweetness in his simple melody. Loggerhead Shrike: Butcher-Bird. The shrike, known among the farmers as mouse-bird and among the boys as butcher-bird, is one of the first to arrive from the south and one of the last to leave. Arriving here the last of Febru- ary or the first of March, its nest is often built and eggs laid before March 25th, while May Day has found the second nest built and eggs incubating. Two different years have I found snow on the ground when the young birds of the first brood were learning to fiy. The shrike’s food consists largely of beetles, grasshoppers, mice and small birds. In localities where English sparrows are very abundant, they furnish most of the shrike’s bill of fare, though I have rarely found them killing our native birds. Their habit of hanging the mice and birds killed on thorns has given rise to the name of butcher-bird. 202 IOWA ACADEMY OP SCIENCE The shrike may he found along the roads near pastures where Hawthorn or crab apple trees are found or where there is an osage orange hedge. His nest is built in such a hedge or in a thorn bush or tree. It is a large, bulky, warm structure resembling somewhat a large king-bird’s nest. Cedar Waxwing. Majestic, stately looking bird of exquisite coloring, the cedar waxwing is quite rare in Polk county during the breeding season, though abundant in the spring and fall and throughout the winter, seen in flocks of from ten to thirty quite frequently, generally in the light woods or orchards. Its food consists of seeds and insects, with occasionally some fruit when it Is convenient. The waxwing’s nest is a deep structure of sticks and fibers, lined with grass and feathers, and located in the crotch of an apple tree or cedar bush a few feet from the ground. Purple Martin. The most common of the swallows in and about Des Moines, the purple martin may be seen on the telephone and telegraph wires throughout the residence districts of our city and along most of the roads leading to it. Their season here is from the middle of April to the first of September. Their nests are built in boxes, corners of buildings and hollow trees, and con- sist of a little heap of leaves and a few straws. Barn Swallow. Next in order comes the barn swallow, known by his long, forked tail, and building his nest of mud and straw on or against tne rafters of the barn or shed within easy access of the willful pilferer. His stay with us is about the same as that of the purple Martin. The diet of all the swal- lows is chiefly insects, caught on the wing. Tree Swallow. This white-bellied swallow is found in some places in Polk county in rather large numbers, especially during the times of gathering be- fore the fall migration. Their general habits correspond very closely with those of the purple martin, both in the time of arrival and departure and their nesting habits. BanU Swallow. Arriving in May and leaving again in late August, the bank swallow makes the shortest stay of all our swallows. He is the smallest of our swallows and builds a nest in a tunnel excavated by himself in a clay bank along a river or railroad cut. This tunnel is lined with grass and feathers, making a soft, warm nest. Other habits the same as the other swallows. Clijf Swallow: Eaves Swallow. This last of the swallows to be considered is, to some of our farmer boys, the best known of them all, for in some local- ities beneath the eaves of every barn are found long rows of these peculiar, gourd-shaped nests of mud, with the opening through the neck, and lined with feathers and straw. Often they are placed so close together that a single mud wall forms the dividing partition. Where there are no desirable buildings upon which to build the nests, they are built under shelving cliffs. The barn swallow is typical of this swallow in other respects. Scarlet Tanager. Once one of our most common and familiar birds, the scarlet tanager is our best local example of the unspeakably pathetic effect of the uncurbed exercise of a semi-savage taste. Together with all of our bril- liantly plumaged birds, the scarlet tanager has been nearly persecuted out of existence, and had not prohibitory laws been passed, the present would have witnessed the list now containing the American bison, the woodcock and the passenger pigeon swelled by another once common Iowa resident. Five years ago it was an exceedingly rare bird in Polk county, but it is now on the in- crease, though its confidence in human kind has not returned. We must now IOWA ACADEMY OP SCIENCE 203 look for it in our deep, secluded woods, though occasionally a pair is found in the more open woods and groves. The tanager’s stay with us is short, being from about May 15th until August 20th. The nest he builds is a rather flat, irregular nest of sticks and root fibers, lined with finer material of the same kind and placed on a high, hori- zontal branch of a white or bur oak tree. English Sparrow. Words strong enough cannot be found to adequately ex- press the denunciation which* the bird lover feels toward this feathered pest that is overrunning our land, destroying our native birds, our grain and our buildings, and scattering weeds and vermin wherever it goes. We all know the habits of this unmitigated pest too well to need description. Let us en- courage and aid in the destruction of the English sparrow wherever possible and thereby do what we can to check their increase and protect our native birds. Vesper Sparrow. We turn now to the well known twilight singer of the road sides and the fields. The vesper sparrow arrives here from the southern states in April and from then on until October you may hear his sweet, clear song from late afternoon until night. His nest is built in a deep depression in the ground and lined with a thick layer of soft grasses neatly woven together. These sparrows are mostly seed eaters, though during the summer, insects and berries also fur- nish part of their feed. Chipping Sparroio. As the vesper sparrow closes the evening chorus of the birds, so the chipping sparrow leads out in the morning melody. This little fellow is perhaps the most common of our native sparrows in Polk county, and being of a sociable turn of mind, is found in almost every locality where the English sparrow is not in too complete possession. Their nests are built of fine grasses lined with horse hair and placed in bushes or trees all the way from the ground up to fifty feet. Song Sparrow. The song sparrow is the most constant singer among our Iowa birds. Arriving here in early March, his song does not cease until he leaves in November, though it changes quality and tune several times. The singer may be found in the open fields, the shrub-dotted pastures, the light groves, the gardens and the orchards, and even in the light woods I have at times come upon him. The nest is built on the ground or in a low bush or clump of weeds, not well hidden as a rule. Swamp Song Sparrow. Not such a singer as his cousin of the upland pas- tures, and much rarer in Polk county, the swamp song sparrow is, neverthe- less, a splendid vocalist and a common summer resident in nearly all the swamps along our rivers and the ponds northwest of Des Moines. They are shy birds and build their nests in the reeds and swamp grass or in small bushes in the swamps and may be found here nearly any time from the first of April until their departure for 'the southern states in late October. Field Sparrow. Another half shy, half bold little songster of the fields and meadows. The field sparrow is quite common in the meadows about Des Moines, though heard much oftener than seen. Its season with us is almost identical with that of the song sparrow, as are also its nesting habits. American Goldfinch: Wild Canary. This cheery, genuine whole-souled little beauty, with his confiding, happy manner and wild carefree, canary-like song, has an individuality all his own. IOWA ACADEMY OP SCIENCE The American goldfinch arrives here late in April, but he stays until late in December before leaving again. Their nests are of the softest possible material, often composed entirely of plant and thistle down. The nest is round and very neat and compact, placed in a bush or a tree where it is well protected by surrounding branches or thorns, and where it is pretty well hidden. Cardinal. The American red bird or cardinal is entered in this treatise of Polk county birds, not because it is a common resident here, but because in the past few years it has become quite a common bird in the southeastern part of Iowa, and I have the boldness to prophesy that in the next ten years it will be frequently found nesting in Polk county. Already I have twice seen the cardinal in our county as a wild bird, and with continued protection I look for it to become one of our much loved Iowa birds. Towhee, ChewinJc or Ground RoHn. The towhee, one of the common sum- mer residents of Polk county, usually arrives about the middle of April. It is one of our shy birds, to be found in the quiet wooded strips along the smaller creeks or near brush thickets, nesting on the ground in a clump of underbrush where the nest is well concealed. The towhee is a very restless bird and is to be frequently found upon the ground scratching among the dead leaves for in- ^sects and seeds which it ea^s with equal relish. The male’s song is typical of the bird, — a wild, defiant, startling series of notes heard only, during the nesting season. He leaves for the south again about the middle of October. Rose-Breasted Groslteak. Naturally a bird of the open woodland, the rose- breasted grosbeak has easily adapted itself to life in the residence district of our city where the trees are of sufficient size. Its season wnth us is from about the first of May to the middle of Septem- ber. It builds a neat, circular nest of fibers and grass, lined with finer grass and placed in a low tree or in a large thornbrush. Its food consists of beetles, flies, larvae, seeds and the buds of various trees. Indigo Bunting. This shy little friend of brilliant hue is fast becoming one of our rare birds in Polk county. Naturally a bird of the quiet, secluded woodland districts, the rapid destruction of our woods and the building of houses in those that are left, have driven this timid little fellow to other haunts. However, in the timber uplands along Beaver creek and Four Mile creek, they are still to be found in some abundance, while in many other smaller wooded tracts they are to be met v/ith occasionally. The indigo bunt- ing is here from the middle of May to the middle of September. Its nest is a rude, bulky structure of sticks and leaves, built in a low bush near the ecge of a thicket or occasionally in a small, bushy tree. Bobolink. I include the bobolink in this work on Polk county birds for a variety of reasons. First, because I have found the bobolink nesting in Polk county a few times. Secondly, because of all birds famed for its song in our middle and northern states, none is more widely known or loudly praised than the bobolink. Thirdly, because several times in the last five years our Des Moines papers have contained articles on the birds found in the vicinity of Des Moines, in which the bobolink was given a foremost place and reported to be a common bird in this locality. Almost the reverse is true. The bobo- link is in reality one of the rare birds in Polk county and will be seldom met with here, though in some parts of Iowa they are found in large numbers. Red-winged Blackbird. One of the very familiar birds of our lowland meadows and marshes and along roadsides is the red-winged blackbird. From IOWA ACADEMY OF SCIENCE ^05 the time of its arrival early in March until it leaves in October, it proves it- self very valuable to the farmer by destroying insects and cutworms in great numbers. Its nest is usually built in the reeds or marsh grass in the edge of a swamp, though I have found them a few times in pine and evergreen trees some distance from any marsh. The nest is a bulky pocket of rush blades and grass, often easily seen but very hard to get to. The red-wing is probably the most common of our blackbirds in Polk county. Bronzed Orackle. The bronzed grackle is in habits so closely the same as the red-winged that no separate description is necessary. They are nearly as common in Polk county as the red-winged species. Rusty Blackhird. These rusty, black fellows are not found in such large numbers in Polk county as the other two kinds just described and yet in the more secluded swamps they are found very frequently. The rusty blackbirds do not migrate in flocks as do the red-wings, but in pairs. Except for that, the description for the red-wings fits this species too. Yellow-headed Blackhird. Some years not found in Polk county at all and other years seen in good sized colonies, the yellow-headed blackbird presents the most surprising sight of his tribe when seen. The yellow-headed blackbirds seem to be diminishing the past few years with the draining of our bigger swamps, and they are probably destined to become a thing of the past in Polk county, at least. When met with, their habits are not essentially different from those of the red-winged. Meadow' Lark. Not a lark at all, but a first cousin to the blackbirds and the bobolink. The meadow lark is common in nearly every meadow in Polk county, and within the past few years seems to be growing more plentiful rather than less so. The meadow larks arrive here about the middle of March and stay until about November 1st. Their nesting habits are almost identical with those of the bobolink except that the nest is more often protected by a tuft of grass acting as a covering. Orchard Oriole. Another relative of the blackbird, the orchard oriole is less common here than the Baltimore oriole. It is very largely a bird of the orchards, building its little cup-shaped nest of green or dried grasses nearly always in a fruit tree in some old orchard in a quiet, secluded place, for the orchard oriole is a very shy bird. Its season with us is from May first until September. The orchard oriole is becoming more rare in the near vicinity of Des Moines, though nearly all the older orchards a few miles away will have one or more pairs each summer. Baltimore Oriole. The Baltimore oriole arrives here from Mexico about the first of May and from then on until the last week of September may be found anywhere in the residence districts of our city and nearly everywhere in the woods where there are large, spreading trees. Their nests are beautiul, pensile pockets, smallest at the top, and suspended from the end of long, swaying branches, from fifteen to seventy feet from the ground. The nests found near the city are made of strings, milkweed, flax, bits of cloth, rope, etc., v/oven compactly together. I have one nest, however, which I found in the deeper woods northwest of Des Moines which contains almost nothing but plant fibers, grasses and strips of bark; a typical nest of the Baltimore oriole before settling up of our wooded district and the con- sequent abundance of more easily utilized material. IOWA ACADEMY OF SCIENCE 2oa Blue Jay. The blue jay, well known for his brilliant plumage, saucy airs, and harsh call notes, is one of the most dreaded foes of the song birds. Through- out'the spring and summer months, these feathered bandits live largely on the eggs and young of our most useful song birds. The fear and hatred felt by our songbirds toward these daring robbers is well illustrated by the fury with which they attack the intruders whenever found near the songbirds’ nest. The blue jay is a yearly resident here and builds a bulky nest of sticks, rags, paper and leaves, in a crotch from ten to fifty feet from the ground in almost any kind of a tree. Crow. The crow, another hated robber, not beautiful like his blue coated cousin but much more discreet and wary, is in other respects just a blue jay “built large,” with a correspondingly larger capacity for the eggs and young of our feathered friends. Both of these birds are worthy of destruction, doing more harm than good and forwarding the feared extermination of some of our rare song-birds. The habits of the crow are almost identical with the blue jay and therefore do not need a separate description. The nest is about three times as large and placed always about^ thirty to sixty feet from the ground, in the deeper wooded districts. ORDEE PASSEEES: PERCHING BIRDS. 8ul)-order Clamatores: Songless Perching Birds. Kingbird. The kingbird has been well named, as all who are in any degree acquainted with this dauntless fighter will heartily agree. He is a born fighter and wages unrelenting war upon all crows and hawks that come within his range of vision. His food consists of insects which are caught on the wing, for the kingbird is a true fiy-catcher. From his arrival with us in early May until his departure in October, he is living on injurious insects and keeping them in check. He is a sociable bird and can be found many times nesting in the residence districts of our city, though most commonly seen on the outskirts of our city and in the light timberland of the country near open fields and pastures. The kingbird’s nest is a rather large, bulky, deeply cupped structure com- posed of sticks, bark and grasses, lined with grass and matted fibers. It is generally placed in a conspicuous place in a crotch or on a horizontal branch in an orchard or thin woods. Great Crested Flycatcher. This largest, most magnificent of our fly-catchers, the great crested, has several characteristics all its own. Being a bird of the deep, quiet woods, it is now becoming much less common in Polk county than a few years ago, though still to be found in several localities in some abun- dance. Its call is a harsh, wild, weird call, suggestive of the bird and its habits. Its nest and eggs are also of a peculiar type, for this is the bird that nearly always lines his nest hollow with a cast-off snake skin. The nest itself is usually placed in a hollow tree or in an abandoned woodpecker’s hole. The eggs are striped with longitudinal markings only, of a rich purple, chestnut and chocolate brown. No other American bird lays eggs of this peculiar type. Their season with us is from May until early October. IOWA ACADEMY OF SCIENCE 207 Phoede. This cheery little flycatcher, the first to come and the last to, leave of its tribe, is well known to all those living in the outskirts of our city or on the farms throughout the country. The phoebe is a favorite because of its confiding sociability and cheerful habits. From its arrival early in April until its departure late in October, U is constantly to be seen and heard as it flits about catching food or building its spongy nest of mud, moss and grass. These nests are bracketed on rocks near running water in the woods, or on rafters or supporting beams of barns, bridges, porches and other buildings. They frequently harbor bird lice in large numbers and are therefore very objectionable about a house. Wood Pewee. Though not a songbird, the wood pewee has a plaintive little strain truly musical. The wood pewee is a very common resident here from May until October and can be found in nearly every strip of woods within the county. Its nest is a flat, lichen covered, mossy home, saddled to a woodland limb slightly softened by decay and growing moss, on which the little nest seems but a knot. Least Flycatcher. This smallest of its tribe is not found in Polk county in very great abundance. His season and habits correspond with the other fly- catchers except that his nest is built in an upright crotch of bush or tree and is composed mostly of plant fibers, weeds and a lining of down or horsehair. This little fellow is usually to be found in orchards during May and Sep- tember when he can be most easily found and recognized. OEDER MACEOCHIRES: SWIFTS, WHIP-POOR-WILLS, ETC. Whip-poor-will. A strange, weird bird of the night, the whip-poor-will is much less common in this vicinity than its close relative, the nighthawk. The whip-poor-will arrives here late in April and leaves about the first of October. Its food consists of night flying insects and moths, which it catches on the wing. The whip-poor-will builds no nest but lays its eggs in a mossy hollow on the ground, usually a good distance from any large number of houses, though often near farm building in secluded nooks. Nighthawk. In all its habits, the nighthawk is so like the whip-poor-will as to need almost no further description. It is a very common resident of Polk county and may often be seen flying about in the evening even far down into the city. Its harsh cry is readily recognized and never to be confused with the distinct cry of the whip-poor-will. The nighthawk has been known often to lay its eggs on the flat roofs of buildings in the city, and though I have never known of that occurring in Des Moines, it is by no means improbable. Chimney Swift. Another bird gaining its food while on the wing, yet neither a fly-catcher nor a swallow nor a close relative of the whip-poor-will, the chim- ney swift is also one of our feathered wonders. He flies and catches his food equally well by night or day, and his loud twitter can be heard nearly any time during the summer. The chimney swift is never seen to perch like other birds, or indeed to alight anywhere except within chimneys or hollow trees. Its claws and tail feathers (the shaft of which extends three-fourths of an inch beyond the vanes) are 208 IOWA ACADEMY OP SCIENCE nearly as sharp as needles and make it easy for them to bracket themselves within the hard brick chimneys. Their nests are open, lattice-work baskets made of small twigs broken from trees as the birds fly by and glued together and to the chimney (or hollow tree, as is the case in wild regions) by a glue secreted as saliva by the birds them- selA^'es. The season of the chimney swift with us is from late April until well into October. Ruby-throated Humming Bird. The only humming bird commonly found in lov/a and the only one that I have ever found in Polk county is the well known little ruby-throated species. They are not very common here, though by no means rare. They are the smallest of our birds and build their tiny nests usually on a horizontal branch where it resembles a tiny knot. The 'nest is made of fern wool, plant down, etc., and covered with lichens or chips of bark. The nest disappears soon after the young birds have left it because of its minute size and the destructiveness of the weather. The humming bird is with us from about the second week in May until some time in October. OEDER PICi: WOODPECKERS, ETC. Hairy Woodpecker. The least common of the five woodpeckers which I shall speak of here, the hairy woodpecker is found in the light woods along the rivers and among the wooded hills throughout the county. He is a dashing, active fellow, a little larger than the red-head and hence easily recognized. He is a yearly resident here most often seen in the fall when the young ones are numerous. This woodpecker, as is the case with the others, drills its nest cavity out in a tree or post from eight to thirty-five feei from the ground. Downy Woodpecker. Just a smaller edition of the hairy, in color and habits, the downy woodpecker is much more common in Polk county as well as being more trustful of the human family. This little fellow may often be seen at all times of year persistently searching the trunks of trees for insects and their larvae and pupae. Yellow-bellied Bapsucker. The sapsucker is a common summer resident, ar- riving here in March and departing in November, and is the one destructive member of the woodpecker tribe. His pernicious habit of drilling rows of holes into our trees, sucking the sap and eating the Cambrian layer of bark, has been the cause of the death of many of our fruit trees, and has brought a hearty hatred for the sapsucker from most of our horticulturists. Red-headed Woodpecker. The red-headed woodpecker is well known wher- ever there is a suitable place for nesing. I am sorry to state, however, that this bird is becoming less common than he was a few years ago, due, I think, to the slaughter practiced by the thoughtless boy, or man, with a gun and no game. Flicker. The flicker, commonly known as the yellow-hammer or golden- winged woodpecker, is at present the most common of our woodpeckers in Polk county. His season with us, as is also the case with the red-head, is from March to November. This is the largest bird of his tribe in this locality, and does a vast amount of good to the farmer and to humanity in general by des- troying countless numbers of insects. IOWA ACADEMY OF SCIENCE 209 The flicker may be found anywhere throughout the residence districts of our city and everywhere in the country, feeding on the trunks of dead trees and decaying stumps, or on the ground like a pigeon. OBDER coccyges: CUCKOS, KIlsmFISHEES, ETC. Yellow-Mlled Cuckoo. We now come to another shy bird of the quiet wood- land. The yellow-billed cuckoo is a beautiful, soft colored bird of secretive habits, and for that reason, not often met with. Being very fond of the tent-worms and their moths, it is frequently to be found in orchards where these worms have gotten a start. Its nest is a flat platform of a few sticks loosely laid together, placed in a bush. This cuckoo’s stay in Polk county is from April until October, and its winter months are spent in the valley of the Amazon. Black-Mlled Cockoo: ^‘Rain Crow.'" Like the yellow-billed species in all its habits, this bird needs no further description. It is, however, more common in Polk county than the yellow-billed. Belted KingfisTier. A relative of the cuckoo, though almost its opposite in everything visible, this dashing, noisy, fearless chap is a common resident here from early March until late November, and can be found anywhere along our rivers and many of the smaller creeks. His home is in a hollow tree or in an earth-burrow from six to eight feet deep in some high embankment along a river or railroad cut. ORBEB, RAPTOEES: BIRDS OF PREY. American Barn Owl. Not a very common owl, and yet one that is frequently met Vv^ith in this part of the state is the American barn owl. It is a harmless bird, feeding on mice, moles, large beetles, etc., and building its nest in barns, belfries, towers, etc. In wuid regions it builds in hollow trees. The owls are all yearly residents here. Screech Owl. The most common of our Polk county owls is this little fel- low, v/hose weird cry is so startling and uncanny on a still night. Also a bird of prey, feeding on mice and moles to a large extent, this fellow is really a benefit to the farmer. Great Horned Owl: ''Hoot Oiol." This great, wild, weird fellow is the most destructive of our owls, and his raids upon the chicken or turkey roost are very disastrous. Now a comparatively rare bird in Polk county, he was once a very common resident, and made the nights hideous by his uncanny cries. The hoot owl will be found now only in the deep, quiet woods where the trees are large and the underbrush thick. Here he still builds his nest in a hollow tree and captures rabbits and raids surrounding poultry yards for his food. Marsh Hawk. This graceful “blue” hawk that is so often seen circling slowly over marshy lowlands is the most beneficial of its family, for it lives entirely on reptiles, locusts, grasshoppers, and small mammals, never touching poultry. It can see to hunt by night as well as by day, and is often hunting the most at that time. 14 210 IOWA ACADEMY OF SCIENCE The marsh hawk builds its nest on the ground in swampy meadows or among rushes in a marsh. With us the marsh hawk’s season is from early March until November, and in mild winters some of them winter here. Sharp-shinned Hawh. Of this small, common hawk. Dr. Abbott says: “It is feathered lightning. He ceases to be before you realize that he is.” Be- cause of his wonderful swiftness and daring, this little hawk is about as destructive of poultry and song birds as the famous chicken hawk which I shall describe next. A frequenter of all wooded districts, this little brigand builds his nest high up in a thick topped tree. The nest itself is a bulky platform of sticks with a nest of bark, leaves and moss in the center of the top. This hawk is a yearly resident. Coopers HawTc: Chicken Hawk. This exceedingly destructive hawk has be- come, in the last few years, much less common than formerly in Polk county, much to the advantage of the song birds and poultry. This bird has not the dash and daring of the sharp-shinned hawk, but is one of the most crafty of our birds of prey. It is a shy bird, and, except where there are chickens, is seldom seen about dwellings, but in and about the wooded strips. Its nest is built in the tops of trees in the thick woods and resembles that of the last named species. During April of 1856 or 1857 a great migratory flight of these hawks was noted, in which hundreds of thousands of the birds were seen to pass over northwest Des Moines in a single day. They flew in flocks like ducks, one flock within easy sight of several others in the general flight and occasionally a hungry hawk was seen to drop suddenly from the flock into a chicken yard below. Red-tailed Hawk: Hen Hawk. The great red-tailed hawk is the most com- mon of our big hawks, and it is the one that scatters the hens in wild con- fusion upon its appearance, for this hawk is easily capable of carrying off a good sized hen. However, it is said that eighty per cent of its food consists of rodents, destructive to agriculture. Its nest is built, as the last one just described, in the top of a tall tree in the deep woods, and there are a few nests to be found every year in Polk county. Red-shouldered Hawk. A trifle smaller than the red-tailed, this other of our big hawks is not quite so often met with in Polk county as is its larger cousin. It is a dignified bird with an owl-like flight but majestic, eagle-like pose when at test. It is also a bird of the deep woods, though it often hunts, as does the marsh hawk, about the marshes where frogs are abundant. Bald Eagle. No longer found resident in Polk county, though occasionally seen here and found nesting in other parts of Iowa, the bald eagle cannot be left out of a treatise on birds without a feeling of incompleteness. This majestic bird was often found here by the early residents in this sec- tion, and in honor to our nation and justice to our state, I take the liberty of this much mention of him, and of suggesting that, while we feel a sentimental regret that the great bald eagle is no longer found here, perhaps it is fortunate for our farmers that this bullying robber is no longer among us. IOWA ACADEMY OF SCIENCE 211 American Sparrow Hawk. This, the smallest and prettiest of our hawks, is also one of the most useful, living on rodents and large insects, with an occas- ional song bird or sparrow. In the country districts throughout Polk county, this little fellow can he frequently met with along the roads and near groves or wooded strips. Rarely a resident, this hawk comes to us usually in March and goes again late in November. Its nest is huilt in a hollow tree or old woodpecker’s hole, and in fact, sometimes in dove-cots. American Osprey: Fish Hawk. One of our most interesting birds of prey, the fish hawk is much less common than formerly in Polk county, though in other parts of Iowa it is still a familiar sight along our rivers. Living almost entirely on fish, which it catches in its large, strong talons, this daring fellow will dive quite deep at times to secure its prey. After such a dive it will frequently emerge from the water, shake a shower of spray from its wings and rise slowly, carrying a five or six pound bass to a convenient tree or high bank where it is consumed. Although a resident here, the osprey is seen most frequently in the spring and early fall (its season with us is from April to November). This eagle-like bird builds its bulky nest in a high tree near or over water, and frequently in almost inaccessible places. Turkey Vulture: Turkey Buzzard. Only twice have I seen these great sca- venger birds in Polk county, and, since the time has come when carrion is no longer left lying about on our prairies or in the timberland of our well settled county, they will never become again, as they once were, familiar residents in this part of the state. Thirty years ago the turkey vulture was as common a resident of Polk county as is the crow today. The vulture’s favorite means of defense was to vomit on the besieging enemy. ORDER, coltjmbae: pigeons. Passenger Pigeons. Forty years ago the wild pigeon was probably the most abundant of our game-birds and migrated in immense fiocks that blackened the sky as they flew over. Today they are so rare that every ^ppearance is care- fully noted. Once only in the past fourteen years of observation have I seen the passenger pigeon in Polk county, Iowa, where once they were killed by the hundreds and left lying as food for the pigs, while others were hauled by the wagon load into our city and shipped to larger places. The woodcock has already gone the way of the wild pigeon, and the quail, prairie chicken, grouse and snipe are in grave danger of the same fate. Let us do all possible to create sentiment and enact laws that will protect them before it is to late. Mourning Dove. These shy but sociable birds are very common in Polk county. Naturally a bird of the quiet woods, they are also found nesting in the residence portions of our city and in nearly every farm yard. The* nest is a loose bunch of sticks thrown together to form a transparent platform on a horizontal branch of almost any .kind of a tree, though a pine or evergreen is preferred. The season here is from March to late November. 212 [OWA ACADEMY OF SCIENCE OEDEE, GALLII^AE: GALLINACEOUS BIEDS. Bo'b-white: Quail. Beginning with the boh-white I shall give only a brief statement regarding each of our more common game-birds and water birds. They are all rapidly becoming rare birds in Polk county as summer residents, and I shall merely try to give a few suggestions as to where they can yet be found. The bob-white is a yearly resident with us and can be found best in the spring and early summer in the quiet, open woods v/here there is considerable underbrush but not a thick growth of timber. In the fall they are often met with in flocks in the fields or woods, but because of the man with the gun are very wild at that time. Their nesting habits are like those of our domestic chickens except that the nest is located in a very quiet, secluded spot, as far as possible from the houses or places of labor of man. Ruffed Grouse: {Pheasant). A bird of the deep, quiet woods, this magni- ficent drummer is still sometimes met with in Polk county. The ruffed grouse is also most easily found in the spring, early April being tiie best month. Only in the deep woods will he now be found, and mostly northwest of Des Moines, in the wooded hills near the Des Moines river or Beaver creek. Prairie Hen: ‘Hrairie Chicken:' More common than the ruffed grouse in this county, we will meet with the prairie hen most often near or in the edge of a grain field near a brush-covered hill or a thick wooded strip. Also a yearly resident, the prairie chicken is seen in the early fall in flocks of from fifteen to fifty, flying from field to field where food is to be found at that time of year. Its nesting habits are also like those of the domestic fowl. OEDEE, LIMICOLAE: SHORE BIEDS. Kildeer Plover. Recognized by its cry, the killdeer plover is abundant one year and very rare the next along our streams and marshes. It nests in swampy meadows, arriving in March and not leaving until late November. It is most easily found in early spring and late summer. American 'Woodcock. The king of our game-birds, the American woodcock is a thing of the past in Iowa, another tribute to the greed of the American hunter, for this bird was also once a well known bird in these parts. I have only found the v/oodcock twice in Polk county, both of those times along the river in the woods between Camp Douglas and the mouth of Beaver creek. Spotted Sandpiper: '^Teeter." As yet a common bird in Polk county, the spotted sandpiper may be found from April until late October along nearly any of our roadside or woodland brooks, and along the rivers and larger creeks. The nest of this sandpiper is to be found in such a location as is chosen by the meadow-lark. OEDEE, paludicolae: ceanes, bails, etc. American Coot: Mud Hen. Still a comparatively common bird about our sw'ampy ponds and river bottoms, the mud hen is known by all the hunters and the boys who spend much time in those places. Arriving here early in March, the mud hen stays until late October or November, building its nest on a decayed reed bed in a swamp or on a mucky tussock in a marshy place where the eggs and young are always damp. [OWA ACADEMY OP SCIENCE 213 ORDER, HERODIONES: HERONS, ETC. American Bittern: Stake Driver. An evil looking inhabitant of the great, lonely marshes, the American bittern is probably almost excluded from Polk county because of the tiling, out of all our bigger swamps. Its season in Iowa is from May to November, and if found any more in Polk county, it will be along our river bottom marshes. I have found it a number of times here, though not in the past three years. Least Bittern. The smallest of its family is still a rather common bird in some of our meadow marshes. It is very hard to find because of its great shy- ness and is always in seclusion near tall reeds or cat tails. Most of our bird students will not find this peculiar little fellow in spite of his comparative abundance. Great Blue Heron: Blue Crane. One of the most picturesque as well as the largest resident bird of Iowa, the great blue heron has in the past few years ceased to reside in Polk county for the same reason as the American bittern. Naturally a very shy, suspicious bird, accustomed to the great, lonely marshes and pond filled meadows, this bird has sought more agreeable locations for nesting. In the early spring and late fall it may yet be seen along our rivers or near our larger ponds where it may make a brief stop in its migratory journey. Green Heron: ''Poke.'' This heron is common in Polk county, and I have several times found one or two pairs in the marshes along the Highland Park car line just north of the river. Most of our marshes contain one or several pairs, and they are not hard to find. Their nests are placed in trees not far from the ground, and are large, bulky structures of sticks and bark. Little Blue Heron. Not different from the green heron, but much less com- mon here. Black-croivned Night Heron. Not so common as the green heron and yet not uncommon, this nocturnal member of the heron tribe will be most often seen in the evening about dusk, fiying slowly from its roost or nesting place in the quiet woods, to some marsh or pond where it will spend the night in quest of food. These birds often nest in colonies, though I have never found it so in Iowa. ORDER ANSERES; LAMELLITROSTRAL SWIMMERS. Mallard. Once a frequent resident of Polk county, but now confined to the larger lakes and mostly to more northern latitudes, this progenitor of our tame ducks is well known as a game-bird, and is to be seen every spring and fall at the time of the migrations. Blue-winged Teal. Less common in the migrations than the green-winged variety, but more common as a summer resident, this duck may often be found nesting near our isolated ponds where wild-grass meadows surround them. The migrations are in early March and November. Green-winged Teal. Not different in habits from the species just described Wood Duck: Summer Duck. This is the most beautifuL of our native ducks, and of late years has also become the most rare. In fact, I have once seen the wood duck in Polk county, and can find very few persons who have found 214 IOWA ACADEMY OF SCIENCE it here within the past five years. This is only another example of the story being so often repeated in our land, of local extermination preceding the gen- eral extermination of our once common, beautiful birds. The wood-duck, un- like all others of its family, builds a feather-lined nest in the hollow of a partly decayed tree near the water and at quite a distance from the ground. From this nest the young are carried in the parent birds’ bills to the water’s edge. ORDER PYGOPODES: DIVING BIRDS. Pied-'billed Gre'he: Hell-diver. This common little fellow can dive at the flash of a gun and be beyond harm before the charge fired has reached its mark. In many ways its eastern name of ‘Mabchick” is most descriptive, for its nest resembles a mud pancake floating on a bed of rushes and covered, in the day time when the sun shines, with a layer of muck which is scraped off at night and the eggs incubated. The pied-billed grebe is a common summer resident in our marshes and ponds, and can generally be found with little difficulty. LIST OP BIRDS TREATED BY FAMILIES. Order Passeres: Perching Birds. Order Passeres: Perching Birds. Suh-Order Oscines : Singing Birds. Family Turdidae : Thrushes American Robin Wood Thrush Wilson’s Thrush : Veery Blue Bird Family Paridae : Nut-hatches and Tit- mice Chickadee White-breasted Nut-hatch Red-breasted Nut-hatch Family Troglodytidae ; Wrens, Thrash- ers, etc. Cat-bird House Wren Long-billed Marsh Wren Short-billed Marsh Wren Family Mniotiltidae : Wood Warblers Black and White Warbler Yellow Warbler Chestnut-sided Warbler Prairie Warbler Ovenbird : Golden-crowned Thrush Maryland Yellow-throat Yellow-breasted Chat American Redstart Family Vireonidae : Vireos Red-eyed Vireo White-eyed Vireo Warbling Vireo Family Laniidae : Shrikes Loggerhead Shrike Family Ampelidae: Waxwings Cedar Waxwing Family Hirundinidae : Swallows Purple Martin Barn Swallow Tree Swallow Bank Swallow Eaves Swallow: Cliff Swallow Family Tanagridae ; Tanagers Scarlet Tanager Family Fringillidae : Finches, Spar- rows, Grosbeaks English Sparrow Vesper Sparrow Chipping Sparrow Song Sparrow Field Sparrow Swamp Song Sparrow American Goldfinch Towhee Cardinal Rose-breasted Grosbeak Indigo Bunting Family Icteridae : Blackbirds, Orioles, etc. Bobolink Cowbird Red Winged Blackbird Rusty Blackbird Bronzed Grackle Yellow-headed Blackbird Meadow Lark Baltimore Oriole Orchard Oriole IOWA ACADEMY OF SCIENCE 215 LIST OF BIRDS TREATED BY FAMILIES-Continued. Order Passeres : Perching Birds. Family Corvidae : Crows, Jays, Mag- pies Blue Jay American Crow Sub-Order Clamatores : Songless Perch- ing Birds Family Tyrannidae ; Tyrant Flycatch- ers Kingbird Great Crested Fylcatcher Phoebe Wood Pewee Least Flycatcher Order Macrochires : Swifts, Whip-poor- wills, etc. Family Caprinsulgidae : Goatsuckers Whip-poor-will Night Hawk Family Micropodidae : Swifts Chimney Swift Family Trochicidae : Humming-birds Ruby-throated Humming-bird Order Pici : Woodpeckers Family Picidae : Woodpeckers Hairy Woodpecker Downy Woodpecker Yellow-bellied Sapsucker Red-headed Woodpecker Flicker Order Coccyges ; Cuckoos, Kingfishers, etc. Family Cuculidae : Cuckoos Yellow-billed Cuckoo Black-billed Cuckoo Family Acedinidae : Kingfishers Belted Kingfisher Order Raptores : Birds of Prey Family Strigidae : Barn Owls American Barn Owl Family Burdonidae : Homed Owls Screech Owl Great Horned Owl : Hoot Owl Family Falconidae ; Falcons, Hawks, Eagles Marsh Hawk Sharp-shinned Hawk Cooper’s Hawk: Chicken Hawk Red-tailed Hawk Order Raporte: Birds of Prey. Family Falconidae: Red Shouldered Hawk Sparrow Hawk American Osprey: Fish Hawk Bald Eagle Family Vultures Turkey Vulture Order Columbae : Pigeons Family Columbidae : Doves and Pig- eons Passenger Pigeon Mourning Dove Order Gallinae : Gallinaceous Birds Family Tetraonidae : Grouse, Part- ridges, etc. Bob-white : Quail Ruffed Grouse Prairie Hen Order Limicolae : Shore Birds Family Charadriidae : Plovers Kill-deer Plover Family Scolopacidae : Snipes, Sand- pipers, etc. American Woodcock Spotted Sandpiper Order Paludicolae : Cranes, Rails, etc. Family Rallidae : Rails, Gallinules, Coots American Coot : Mud Hen Order Herodiones: Herons, etc. Family Ardeidae : Herons, Bitterns, etc. American Bittern Least Bittern Great Blue Heron Green Heron Little Blue Heron Black-Crowned Night Heron Order Anseres : Lamellirostral Swimmers Family Anitidae : Ducks, Geese, etc. Mallard Green-winged Teal Blue Winged Teal Wood Duck Order Pygopodes : Diving Birds Family Podicipidae : Grebes Pied-Billed Grebe : Hell-diver Migration of Nervous Eiements. V IOWA ACADEMY OF SCIENCE 217 THE MIGRATION OF NERVOUS ELEMENTS INTO THE DORSAL AND VENTRAL NERVE-ROOTS OF EMBRYOS OF THE PIG.* BY ALBERT KUNTZ. With two Figures. That nervous elements migrate peripherally from the neural tube, during early embryonic development, has been observed by several investigators. Har- rison (’01) called attention to medullary cells migrating into the ventral nerve- roots of embryos of the salmon. Bardeen (’03) observed that “in mammals, as well as in the lower vertebrates, a certain number of cells wander out from the spinal ganglia and cord along with the bundles of axis-cylinder processes.” In his work on embryos of the chick. Carpenter (’06) has shown that cells of an indifferent character migrate from the ventral wall of the mid-brain along the oculomotor nerve and become transformed into nerve cells of the ciliary ganglion. In a more recent paper Carpenter and Main (’07) have described the migration of medullary cells into the ventral nerve-roots of embryos of the pig. In his study of the earliest differentiations in the central nervous system, Schaper (’97) has shown that the germ cells (Keinzellen) of His cells of epi- blastic origin undergoing mitotic division near the internal limiting membrane of the medullary tube — give rise to cells ^vhich he characterizes as indifferent, which migrate toward the mantle layer and are there transformed either into neuroblasts or into embryonic supporting cells. In the higher vertebrates some of these indifferent cells undergo further division by mitosis in the mantle layer, thus giving rise to other indifferent cells after having migrated from their original position. ■ In the cells which Carpenter and Main observed migrating into the ventral nerve-roots of embryos of the pig, they have recognized the indifferent cells of Schaper. In studying embryos of the pig for the purpose of tracing the development of the sympathetic nervous system, the writer has observed medullary cells migrating into both ventral and dorsal nerve-roots. In transverse sections of embryos of the pig from 9 to 13 mm. in length, breaches of considerable extent in the external limiting membrane of the medullary tube may be observed in the region of the ventral nerve-roots. Among the fibers of the nerve-roots passing through these breaches cells may be observed migrating out from the neural tube (fig. I). I have been able to substantiate the observation of Car- penter and Main that cells may be found “just inside the external limiting membrane, in an intermediate position half in and half out of the neural tube, and in the base of the nerve-root just outside the external limiting membrane.” *From the Laboratories of Animal Biology of the State University of Iowa. 218 IOWA ACADEMY OF SCIENCE Among these migrating cells I also recognize, as did they, the indifferent cells of Schaper. In several sections, however, cells with large rounded or elongated nuclei and cytoplasm drawm out to a point at one side were observed among the fibers of the ventral nerve-root, migrating with the indifferent cells. In these cells I recognize the neurohlasts of Schaper.. They are much fewer in number than the indifferent cells but are distributed indiscriminately among them. When observed in the spinal nerve-roots the tapering end is usually directed peripherally. This, also, is in accordance with the usual position of the neurohlasts in the mantle layer. The orientation of the cells in the neural tube is such that two general courses of migration into the ven- tral nerve-root may he recognized; the one directly outward from the ventral zone; the other ventro-laterally toward the base of the nerve-root, from the region in which later the lateral horn of the gray matter arises. In transverse sections of embryos of the pig 6 and 7 mm. long, breaches in the external limiting membrane of the neural tube occur quite frequently in the region of the dorsal nerve-root. Through these breaches medullary cells migrate so freely that in many sections lines of cells practically touching each other end to end can be traced from the mantle layer Into the proximal part of the dorsal nerve-root (fig. II). Further evidence for the migration of medullary cells into the dorsal nerve-roots is seen in the fact that in many sections of embryos 6 and 7 mm. long, where no breaches occur, cells are found in contact with the external limiting membrane in the region of the dorsal nerve-root. In embryos 9 mm. and over in length this area, as shown in fig. I, is always occupied by fibers of the dorsal nerve-root, and rarely are cells found among them. Two general courses of migration may also be rec- ognized in the dorsal region. One of these courses has its origin in the dorsal zone. Some of its cells move in a slight curve directly toward the dorsal nerve-root, others pass from the most dorsal region along the inner surface of the external limiting membrane. The other course tends dorso-laterally from regions ventral to the dorsal nerve-root. The cells of the latter course probably originate in the same region as those which move ventro-laterally toward the ventral nerve-root. Among the cells migrating into the dorsal nerve-roots, I recognize both the “indifferent cells” and the “neurohlasts” of Schaper. My observations do not permit me to conclude how early the first migration of cells from the neural tube takes place. In studying a very young embryo in which, however, the external limiting membrane was completely formed, no migrating cells could be observed. It is probable, therefore, that cells do not migrate out of the neural tube until the fibers of the nerve-roots have pene- trated the external limiting membrane. As observed above, cells are rarely found among the fibers of the dorsal nerve-root near the external limiting membrane inside the neural tube, in embryos 9 mm. and over in length. Migration into the dorsal nerve-root pro- bably ceases before a length of 9 mm. is reached. Migration into the ventral nerve-root continues longer and seems to be most active in embryos from 10 to 13 mm. in length. In embryos over 13 mm. in length migration is rarely observed and probably does not continue far beyond that stage. There are four points to which the writer wishes to call special attention in this paper. (1) Medullary cells migrate into both dorsal and ventral nerve- roots. (2) These migrating cells seem to have their origin in more or less IOWA ACADEMY OF SCIENCE 219 definite regions in the neural tube. (3) Migration from the neural tube seems to be limited to a comparatively short period during embryonic development. (4) While the majority of the cells which migrate into the dorsal and ventral nerve-roots are cells of an indifferent character, cells may be recognized among them, which are to be regarded as the neurohlasts of Schaper. These observations give rise to an important question. What is the destiny of those cells which migrate from the neural tube into the dorsal and ventral nerve roots? This question the writer hopes to consider more fully in a later paper. But, as the way has been opened for a priori speculation a few sug- gestions may be ventured here. Harrison (’01) has already suggested the possibility that the medullary cells which he saw migrating into the ventral nerve-roots of embryos of the salmon may wander farther peripherally, i. e., into the sympathetic ganglia, and there give rise to sympathetic motor neurones. Bardeen (’03) suggests that the cells which wander out from the spinal ganglia and cord along with the bundles of axis-cylinder processes of the nerve-roots may take some part in the formation of the neurilemma, but believes with Vignal and Gurwitsch that in mammals the cells composing the neurilemma arise largely from mesen- chyme. Harrison’s experimental observations on the tadpole (’06) seem to prove that some of the elongated cells found among the fibers of developing nerves, which become cells of the neurilemma, are derived from spinal ganglia. Carpenter and Main (’07) “feel sure” that some of the medullary cells which escape from the neural tube become cells of the neurilemma, and there sub- serve a supporting function similar to that of the neuroglia cells in the central nervous system. Thus far only cells of an indifferent character have been considered. May not the fact that neuroblasts migrate with the indifferent cells into both dorsal and ventral nerve-roots shed some new light on the entire problem? To trace these cells to their ultimate destination is a matter of extreme difficulty, if not impossibility, with the aid of present staining methods alone. In the light of Schaper’s researches, however, we must conclude that the neurohlasts which migrate into the dorsal and ventral nerve-roots have already undergone differentation and must develop into neurones. Having once passed beyond the borders of the neural tube they must migrate farther peripherally. Nothing seems more probable, therefore, than that they should wander along the visceral ramus and give rise to neurones in the sympathetic ganglia. Any conclusion, however, on this point would at present be hasty. We feel that these migrant cells, both the “Indifferent cells” and the “neurohlasts” of Schaper, are fraught with great potentialities and invite the most careful scrutiny into their fate. LITERATURE CITED. Bardeen, C. R., ’03, The Growth and Histogenesis of the Cerebro-spinal Nerves in Mammals. Amer. Journ. Anat., Vol. 2, No. 2, p. 231. Carpenter, F. W., ’06, The development of the Oculomotor Nerve, the ciliary Ganglion, and the Abducent Nerve, in the Chick, Bull. Mus. Comp. Zool. Harvard Coll., Vol. 48, No. 2, p. 241. Carpenter, P, W. and Main, R. C., ’07, The Migration of Medullary Cells into the Ven- tral Nerve-roots of Pig Embryos, Anatomischer Anzieger, Vol. 31, No. 11-12, p. 303. Gurwitsch, A., ’00, Die Histogenese der Schwann’ schen Sheide, Arch. f. Anat. u. Physio., Jahrg. 1900, Anat, Abt., Heft 1-2, p. 85. 220 IOWA ACADEMY OF SCIENCE Harrison, R. G., ’01, Ueber die Histogenese des peripheren Nervensystems bei Salmo salar. Arch. f. mkr. Anat. Bd. 57, p. 354. , ’06, Further experiments on the Development of Peripheral Nerves. Amer. Journ. Anat. Vol. 5, No. 2, p. 121. SCHAPER, A., ’97, Die fruhesten Differenenzierungsvorgange im Centralnervensystem. Arch. f. Entwick. — Mech., Bd. 5, Heft 1, p. 81. — Abstract in Science, N. S., Vol. 5, No. 115, p. 430. EXPLANATION OP FIGURES. Fib. I. Transverse section of neural tube and spinal ganglion of a 12 mm. embryo of the pig. XI65. ' dnr — dorsal nerve root, spg — spinal ganglion, nb — neuroblast, vnr — ventral nerve-root, ic — indifferent cells. Fig. II. Transverse section of neural tube and spinal ganglion of a 6 mm. embryo of the pig. XI65. ic — indifferent cells. dnr — dorsal nerve-root. nb — neuroblast. spg — spinal ganglion. IOWA ACADEMY OF SCIENCE 221 SOME OBSERVATIONS ON THE EMBRYOLOGY OF CHIRONOMUS. BY W. N. CRAVEN. A. INTRODUCTION TIME AND PLACE OF LAYING. All the eggs used in the following investigation were collected from a small pond in the eastern edge of the city of Indianola. The eggs were gathered from time to time at intervals of from one to three days, between June 20th and September 30th, 1902. They were found in abundance along the bank, in water from one to six inches deep. Usually they were attached to a piece of wood, or some plant growing in the edge of the water. Many were also found attached to the bottom. A few were found floating in the water, but as by far the greater number were attached, it is probable that those found floating had broken from their attachment, or by some accident had not been fastened. It w'as found that the eggs collected in the early morning were alwmys con- siderably advanced in their development; so that some of them must have been deposited the previous day. Those collected in the early afternoon were always at least in the early stages of development, while the most freshly laid eggs were collected about ten o’clock A. M. As the insects were always present about the edges of the pond in the early morning, it is probable that some little time, perhaps two or three hours, were consumed in depositing and fastening an egg mass. It is probable that the greater number were laid in the early morning — before ten A. M. As all the eggs in which the first stages of develop- ment had been reached were found about noon, by far the greater number must have been deposited in the early morning. B. THE EGG MASS. The eggs are laid in a clear jelly like mass, w^hich is about three-eighths of an inch in diameter and varying from one-fourth to three-fourths, or some- times nearly an inch in length. The egg mass was always attached by one end, and since its specific gravity is less than that of water, it assumes a nearly vertical position in the water. The eggs are arranged in the mass in the form of a spiral, which runs the length of the mass. The eggs are placed with their long axes in the line of the spiral, each egg lying slightly above and its end projecting over its predecessor. Hence in the normal position of the eggs in the water the embryo lies with its long axis nearly horizontal. ^ C. TIME OF INCUBATION. The time of incubation varied considerably for different egg-masses, although those of the same egg mass always hatched within two or three hours of the same time. 222 IOWA ACADEMY OF SCIENCE The shortest period in which any hatched was about seventy-five hours; the longest period was about 110 hours. The time of incubation seemed to depend almost entirely upon the temperature and sunshine. Those kept at a tempera- ture above 80 degrees P. and in the sunshine developed most rapidly, while those which were away from the light and cooler developed more slowly. In those egg masses which were kept in conditions such that they developed more slowly there were found more eggs which did not hatch. This would seem to indicate that any considerable reduction of temperature or deprivation of sunlight would entirely prevent development. No accurate observations were made, however, upon this point. D. THE EGG. The eggs are elongated-oval appearing slightly larger at the extremity which is to become the anterior, when viewed dorso-ventrally. When viewed from the side they appear more convex on the side which is to become the ventral, the dorsal side in the majority of cases appearing slightly concave, through part of its length. (See fig.) The eggs vary somewhat in size. Prom a number of measurements, the average size was found to be very close to 1-21 inch in length by 1-50 inch in thickness. Prom these measurements individual eggs varied as much as 1-240 inch in length and 1-500 inch in thickness, or very nearly 10 per cent. The choroin is perfectly transparent, and sornewhat flexible, allowing the egg to be distorted by pressure from the cover glass, without breaking. After hatching the empty shell was quite flexible. No micropile was observed. The vitelline membrane does not fit against the choroin at all points, but is drawn av/ay at the ends, usually more at the posterior end. The egg contents are composed almost entirely of the nutritive yolk sub- stance. There is very little of the outer protoplasmic layer present (keim- hautblasten of Weisman). The yolk has a yellowish green color, is very granular, and highly refractive. Numerous oil globules of varying size can be seen scattered through it. In some of the eggs collected late in the season the yolk had a more brownish color. They seemed to be identical with those previously obtained in other respects. Only a few of these were obtained and it was not determined whether they belonged to different species, or the change in color was due to the lateness of the season. E. EAKLY STAGES IN DEVELOPMENT. The first change noticeable was a slight drawing in of the vitelline mem- brane at each end. Shortly afterward there appeared at the anterior end four rather large, quite granular cells (PI. 1, fig. 1-a). About an hour later other cells not so large began to appear on the surface of the yolk. These form a layer (PI. 1, fig. 2) which increases in thickness and number of cells by addi- tion from within, until an irregular layer of cells, the blastoderm, of com- pard'tively considerable thickness, covers the entire surface (PI. I, fig 3.) The cells then arrange themselves regularly and form a layer of columnar cells, the blastoderm covering the yolk. During these changes the large cells are at all times distinctly visible at the anterior end of the egg (PL 1, figs. 2, 3 and 4-a). When the formation of the blastoderm begins, the egg contents crowd out to the end, entirely filling the cavity of the shell. IOWA ACADEMY OF SCIENCE 223 There next appears at the dorsal, anterior end, a thickening of the cell layer, by addition of new cells beneath the surface layer (PL I, fig. 5-p). This is the beginning of the primitive band. At the same time the blastoderm begins to fold in above this point, and as the cells underneath increase in number the fold pushes them downward and backward (PL I, figs. 7 and 8.) While the above changes are taking place the cells of the blastoderm crowd away from the sides, so that now it forms a band completely surrounding the egg. A dorsal view of this stage is seen in Plate II, figure 3. The fold noticed above makes the first segment of the embryo, the pro- cephalic lobes. It is pushed around to the ventral side of the embryo (PL II, figs. 4 and 5) and at the same time the ventral part of the fold becomes con- stricted laterally. Plate II, figures 1 and 2, are diagrams showing the relations of the parts of the fold, at this time, as viewed from the dorsal and ventral aspects respectively. The sides are next folded in in the line of the groove so that in ventral and dorsal views the procephalic lobe is plainly visible (PL II, figs. 6 and 7). A little later the infolding of the primitive band to form the stomodoeum begins, and at the same time a longitudinal groove, the gastrula invagination, extends along its ventral side. Plate II, figure 6-g, represents the first beginning of the gastrula infolding. F. FORMATION OF THE SEGMENTS. Following the gastrula invagination, and the formation of the procephalic lobes, the primitive band grows rapidly backward. The yolk is pus.hed up to the dorsal side, and the embryo lies as a band extending about the egg but not meeting on the dorsal side. As the primitive band extends backward from the procephalic lobes it becomes constricted by transverse furrows which divide it into segments. The mandibular segment is the first to appear, then the first and second maxillary segments. Following these, the segments ap- pear in a general way in succession from before backward. Frequently, how- ever, two or three segments seem to be formed almost simultaneously. G. THE PROCEPHALIC LOBES. In the first place the procephalic lobes are represented by a somewhat globu- lar fold at the anterior end of the primitive band (PL II, figs. 6 and 7). There soon appears on the ventral median surface on the fold a depression (PL II, fig. 8-a). As this deepens the anterior wall of the lobes is thickened and the lateral portions are pushed backward, forming a slight fold so that the pro- cephalic lobes proper become smaller in size. The mandibular segment crowds forward on each side apparently absorbing this fold. H. THE APPENDAGES. (a) The antennae. The antennae appear as buds from the base of the procephalic lobes just in front of the mandibular segment. They are first noticeable as small projec- tions near the dorsal part of the head (PL III, fig. 2-a). This takes place about the 30th hour of incubation. The antennal bud grows downward along 224 IOWA ACADEMY OF SCIENCE the side of the head fold and in front of the mandibular segment, becoming somewhat thicker at the same time (PL III, a). The segments do not appear in the antennse until near the close of embryonic life. They then appear as constrictions of the already formed antennse, not by the addition of segments from behind. At the close of embryonic life the antennse are composed of three segments (PI. Ill, figs. 10 and 12-a). (b) The mandibles . The mandibles appear as appendages of the second segment. This segment is divided laterally into two parts, by the appearance of the gastrula invagina- tion and the stomodoeum, almost as soon as it appears (PI. II, fig. 8). Almost immediately the tw'o lobes move forward to the sides of the antennal segment (PL II, fig. 10-m). As the embryo develops these rudimentary mandibles be- come narrower and longer (PL III, figs. 5 and 7-md.) About six or eight hours before the time of hatching they have grown downward and are visible in a ven- tral view of the embryo (PL III, figs. 5 and 7 md.) A short time before hatch- ing they becom^e divided into two segm.ents by a very slight constriction, and the distal segment develops into a sharp pointed organ. This is the larval mandible. (c) The maxillae. The first maxillge develop as appendages of the third segment. This segment, like the mandibular segment, becomes divided by a dorso-ventral constriction almost as soon as it is formed, and begins to move forward as two lobes, which constitute the rudimentary appendages and their attachment. The anterior edge of this segment moves forward until it is slightly in front of and outside the posterior edge of the procephalic lobes. (PL III, figs. 2, 3 and 6, 1st mx.) The maxillse grow downward a.nd inwa,rd (PL III, fig. 11, 1st mx.), and just before the close of embryonic life a small segment is formed at the end. In the newly hatched larva there is visible a third, very srnall segment at the extremity of the maxilla. The second maxillas are very little developed. They appear as slight pro- truberances of the fourth segment. They are noticeable just before hatching (PL II, fig. 11-m). " id) The thoracic appendages. No appendages are visible upon the thoracic segments until near the close of embryonic life. About eight to ten hours before hatching there appear upon the first thoracic segment a pair of appendages. These are not as yet seg- mented and lie close together on the ventral surface of the embryo (PL III, figs. 8, 10, 11 f.) These develop into blunt rounded appendages, upon the surface of which there appear, -just before hatching, a number of setae. These are notice- able in figures 8, 10, 11 and 12, Plate III. They serve as legs during the larval life of the insect. (e) Abdominal appendages. No abdominal legs were observed at any time. On the ventral surface of the last segment, however, appear a pair of large tubular appendages, fringed with IOWA ACADEMY OF SCIENCE 225 a circle of cilia about their external opening. These are in connection with the tracheal system, a tube from which extends along their entire length, opening at the distal extremity. They serve as larval respiratory organs. They may be seen in the embryo in figure 7, Plate III, r., and in the newly hatched larva. DESCRIPTION OF PLATE I. Fig. 1. The egg 2 or 3 hrs. after laying. (a) Large, cells which later develop into the reproductive organs. - - - - - • - • - Fig. 2. The eggs at about 2 or 4 hrs. showing the layer of blastodermal cells, (a) Large reproductive cells. Fig. 3. The egg at about an hour later than in fig. 2, showing the thickened layer of blastodermal cells, and the large reproductive cells still visible at a. v Fig. 4. The egg at about the sixth hr. of incubation. v-K \ (a) reproductive cells. [• (b) cells arranged in a columnar layer forming the blastoderm. Fig. 5, The reproductive cells have retreated to the. interior and are no longer visible, (p) The beginning of the primative band. Figs. 6 and 7. A little later than 5, showing the first infolding of the blastoderm, (v) Vitelline membrane. Fig. 8. Egg at about hr. of incubation. (v) Vitelline membrane. (p) Begin- ning of stomodoeum. DECRIPTION OF PLATE II. Figs. 1 and 2. Diagram showing the form of the first fold at the anterior end. In fig. 1 as viewed from the dorsal and fig. 2 ^s viewed from the ventral sides. Fig. 3. Dorsal view at the same stage showing the yolk mass crowded to the sides, the blastoderm forming a complete dorso-ventral band. Figs. 4 and 5. Showing the fold pushed to the ventral side and baclgvards. Fig. 6. Ventral view of embryo. (p) procephalic lobe. (g) beginning of gastula invagination, (s) beginning of proctodoeum. Fig. 7. Dorsal view of stage shown in fig. 6. (p) procephalic lobe, (s) proctodoeum. Fig. 8. Egg at about eighth hr. of incubatiori. (v) Vitelline membrane. ,(p)‘-Begin- (m) Mandibular segment, (g) Gastrula. Figs. 9 and 10. Two views about 4 and 7 hrs, later than fig. 8, showing the divided mandibular segment (m) pushing upward on each side of the procephalic lobes and carrying with it the antennal point (a). - - " Fig. 11. Dorsal view of embryo at same stage as fig. 10. Fig. 12. Ventral view of embryo at same stage as fig. 10. ( m )■'' Divided mandibular segment. DESCRIPTION OP PLATE III. ; - Pigs. 1 and 2. Two views of the anterior parft of the embryo at about 28 hrs-32 hrs. (a) antennae (md) mandibular segment. (1 mx). First maxillary segment. (2 mx) second maxillat-y segment. v,. . V Fig. 3. Side view of the entire embryo a little later' than in fig. 2, showing thoracic and abdominal segments. Lettering as in fig. 2. Pigs. 4, 5, and 6. Dorsal ajid' ventral views of the anterior Portion of the embryo, and entire side view at about 40 to 45 hrs. Lettering as in fig. 2. Fig. 7. Ventral view of embryo at about 55 hrs. to 60 hrs., showing mandibles begin- ning to form (md) and respiratory appendages at r. Pigs. 8 and 9. Side and ventral views about 5 hrs. later than fig. 7. Figs. 10 and 12, Side and ventral views of the anterior and of the embryo just before hatching. Lettering as in figs, above. Pig. 12. Side view of the entire embryo just before hatching. Fig. 13. Optical section of embryo just before hatching, showing proctodoeum, stomo- doeum, nerve-cord, and the still prominent sexual cells. 15 226 IOWA ACADEMY OF SCIENCE (Craven. CMronomus.) 228 IOWA 'ACADEMY OF SCIENCE 4 4 (Craven. CWromonus.) 0 IOWA ACADEMY OF SCIENCE 229 INDEX Page Arterio Sclerosis, The Relative Frequency of, of the Various Arteries 193 Balance, Effect of Temperature Inequalities on 181 Battery, The Googler Primary. 167 Birds, Summer Resident, of Polk County, Iowa ' 197 Carbonic Column of Rio Grande Region 159 Cranial Nerves, Fifth and Seventh, in Plethodon Glutinosus. 189 Embryology of Chironomus, Some Observations on 221 Evaporation from Free Water Surfaces 185 Fungus Diseases of Plants, Notes on Factors in 41 Hysteresis Loop 165 Iowa Ground Waters, Some Features of, II 135 Iowa Rock, The Flora of. 99 Manure, The Action of, on a Certain Soil 103 Nervous Elements, The Migration of, into the Dorsal and Ventral Nerve- Roots of Embryos of the Pig 217 Okoboji Lakeside Laboratory 131 Orotaxial Geologic Correlation and Diastrophism 153 Polyporaceae, Some Parasitic 23 Polyporaceae of Fayette, Iowa 19 President’s Address 11 Smaltite, The Analysis of, with Special Reference to the Estimation of Arsenic and Cobalt 143 Thrust-Planes, Significance of, in the Great Basin Region 151 Underground Organs of a Pew Weeds 31 Viburnum Nudum, The Fruit of 145 AUTHOR’S INDEX. Galvin, Samuel ll . Craven, W. N 221 Fagen, Lester P 197 Pogel, Estelle D 31 Hendrixson, W. S 135 Keyes, Charles R 151, 153, 159 King, Charlotte M. 41 Knight, Nicholas 143, 145 Kuntz, Albert 217 Learn, Clarence D 23 Lott, Robert H 145 Macbride, Thomas H 131 230 iOWA academy of science Page Morehouse, D. W 165 Norris, H. W 189 Pammel, L. H 31, 41 Sanders, W. E 193 Smith, Arthur G 185 Watson, E. B 103 Weld, L. D 181 Wilson, Guy West 19 Woodrow, Harry Ray. 165, 167 Wylie, R. B 99