Part 68

Of the many investigators working on the various groups of animals at this time only a few may be mentioned. The protozoa were studied by Leidy, Clark, Ryder, Stokes; the sponges by Clark, Hyatt; the coelenterates by A. Agassiz, S. F. Clarke, Verrill; the echinoderms by A. Agassiz, Brooks, Kingsley, Fewkes, Lyman, Verrill; the various groups of worms by Benedict, Eisen, Silliman, Verrill, Webster, Whitman; the mollusks by A. and W. G. Binney, Tryon, Conrad, Dall, Sanderson Smith, Stearns, Verrill; the Brachiopods by Dall and Morse; the Bryozoa by Hyatt; the crustacea by S. I. Smith, Harger, Hagen, Packard, Kingsley, Faxon, Herrick; the insects by Packard, Horn, Scudder, C. H. Fernald, Williston, Norton, Walsh, Fitch, J. B. Smith, Comstock, Howard, Riley and many others; spiders by Emerton, Marx, McCook; tunicates by Packard and Verrill; fishes by Baird, Bean, Cope, Gilbert, Gill, Goode, Jordan, Putnam; amphibians and reptiles by Cope; birds by Baird, Brewer, Coues, Elliott, Henshaw, Allen, Merriam, Brewster, Ridgway; and the mammals by Allen, Baird, Cope, Coues, Elliott, Merriam, Wilder.

Interest in the evolutionary theory continued to increase and eventually developed into the morphological and embryological studies which reached their culmination between 1885 and 1890 under the guidance of Whitman, Mark, Minot, Brooks, Kingsley, E. B. Wilson and other famous zoologists of the time. In these years the Journal of Morphology was established and the American Morphological Society was formed.

The morphological, embryological and paleontological evidences of evolution as indicated by homologies, developmental stages and adaptations were the most absorbing subjects of zoological research and discussion.

Zoology in the American Journal of Science, 1870–1918.

The third series of the Journal (1870–1895), likewise including fifty volumes, embraces this period of zoological activity in morphological and embryological studies, culminating with the inception of the modern experimental methods.

In this period also occurred the greatest progress in marine systematic zoology, due to the explorations of the United States Fish Commission off the Atlantic Coast. The Journal had an important share in the zoological development of this period also, for A. E. Verrill, who was now an associate editor, was in charge of the collections of marine invertebrates. Consequently most of the discoveries in this field were published in the Journal in numerous original contributions by Verrill and his associates. The explorations of the U. S. Fish Commission Steamer “Albatross” are described from year to year by Verrill, with descriptions of the new species of invertebrates discovered.

The numerous original contributions by Verrill on subjects of general zoological interest as well as on those of a systematic nature give this third series of the Journal much zoological importance. Verrill’s papers cover almost the whole field of descriptive zoology, but are mainly devoted to marine invertebrates. Those which were originally contributed to the Journal or summarized by him in his literature reviews include the following topics:

Sponges, =16=, 406, 1878.

Coelenterates, 37, 450, 1864; =44=, 125, 1867; =45=, 411, 186; =46=, 143, 1868; =47=, 282, 1869; =48=, 116, 419, 1869; =49=, 370, 1870; =3=, 187, 432, 1872; =6=, 68, 1873; =21=, 508, 1881; =6=, 493, 1898; =7=, 41, 143, 205, 375, 1899; =13=, 75, 1902.

Echinoderms, =44=, 125, 1867; =45=, 417, 1868; =49=, 93, 101, 1870; =2=, 430, 1871; =11=, 416, 1876; =49=, 127, 199, 1895; =28=, 59, 1909; =35=, 477, 1913; =37=, 483, 1914; =38=, 107, 1914; =39=, 684, 1915.

Worms, =50=, 223, 1870; =3=, 126, 1872.

Mollusks, =49=, 217, 1870; =50=, 405, 1870; 3, 209, 281, 1872; =5=, 465, 1873; =7=, 136, 158, 1874; =9=, 123, 177, 1875; 10, 213, 1875; =12=, 236, 1876; =14=, 425, 1877; =19=, 284, 1880; =20=, 250, 251, 1880; =2=, 74, 91, 1896; =3=, 51, 79, 162, 355, 1897.

Crustacea, =44=, 126, 1867; =48=, 244, 430, 1869; =25=, 119, 534, 1908.

Ascidians, =1=, 54, 93, 211, 288, 443, 1871; =20=, 251, 1880.

Dredging operations and marine fauna, =49=, 129, 1870; =2=, 357, 1871; =5=, 1, 98, 1873; =6=, 435, 1873; =7=, 38, 131, 405, 409, 498, 608, 1874; =9=, 411, 1875; =10=, 36, 196, 1875; =16=, 207, 371, 1878; =17=, 239, 258, 309, 472, 1879; =18=, 52, 468, 1879; =19=, 137, 187; =20=, 390, 1880; =22=, 292, 1881; =23=, 135, 216, 309, 406, 1882; =24=, 360, 477, 1882; =28=, 213, 378, 1884; =29=, 149, 1885.

Miscellaneous, =39=, 221, 1865; =41=, 249, 268, 1866; =44=, 126, 1867; =48=, 92, 1869; =3=, 386, 1872; =7=, 134, 1847; =10=, 364, 1875; =16=, 323, 1878; =20=, 251, 1880; =3=, 132, 135, 1897; =9=, 313, 1900; =12=, 88, 1901; =13=, 327, 1902; =14=, 72, 1902; =15=, 332, 1903; =24=, 179, 1907; =29=, 561, 1910.

S. I. Smith describes the metamorphosis of the Crustacea (=3=, 401, 1872; =6=, 67, 1873), species of crustacea (=3=, 373, 1872; =7=, 601, 1874; =9=, 476, 1875), and dredging operations in Lake Superior (=2=, 373, 448, 1871). In this series occurs also a series of papers on comparative anatomy and embryology from the Chesapeake Zoological Laboratory in charge of W. K. Brooks. In the 39th and 40th volumes of the third series (1890) occur several papers on evolutionary topics by John T. Gulick (=39=, 21; =40=, 1, 437) which have attracted much attention.

Before the end of this period, however, the Journal was relieved from the necessity of publishing zoological articles by the establishment of several periodicals devoted especially to the various fields of zoology. We find, therefore, but few exclusively zoological papers after 1885, although articles of a general biological interest and the reviews of zoological books continue.

In the fourth series of the Journal, beginning in 1896, occur also a number of articles on systematic zoology by Verrill and others and several papers having a general biological interest. Brief reviews of a small number of zoological books are still continued, but at the present day the Journal, which played so important a part in the early development of American zoology, has been given over to the geological and physical sciences in harmony with the modern demand for specialization.

Period of Experimental Biology, since 1890.

Zoological studies remained in large measure observational and comparative until about 1890 when the experimental methods of Roux, Driesch and others came into prominence. Interest then turned from the accumulation of facts to an analysis of the underlying principles of biological phenomena. The question now was not so much what the organism does as how it does what is observed, and this question could be answered only by the experimental control of the conditions. These experimental studies met with such remarkable success that in a few years the older morphological studies were largely abandoned, the Morphological Society changed its name to the Society of Zoologists, and in 1904 the Journal of Experimental Zoology was established. The experimental methods were applied to all branches of biological science, and while it must be freely admitted that little progress has been made toward an understanding of the ultimate causes which underlie biological phenomena, a great advance has been made in the elucidation of the general principles involved.

Experimental embryology, histology, regeneration, comparative physiology, neurology, cytology, and heredity have in recent years successfully adopted an experimental aspect and have made significant progress thereby. Biology has now taken its place beside chemistry and physics as an experimental science.

The latest great advance in biology has been in the field of heredity. The rediscovery of the Mendelian principles of heredity in 1900 brought to light the most important generalization in biology in recent times. The new science of genetics is essentially the experimental study of heredity.

We are at the moment in the midst of an effort to establish in biology a few relatively simple laws by using for the purpose the vast accumulations of observational data gathered in past years, supplemented by such experimental data as have been provided by these more recent investigations. Such hypotheses as have been formulated are for the most part only tentatively held, for their validity is generally incapable of a critical test. But wherever such tests have been possible, the laws of mathematics, physics and chemistry are found applicable to biological phenomena.

The number of investigators has now become so great and their activities so prolific that the list and synopses of the zoological publications each year cover upwards of 1000 to 1500 pages in the International Catalogue of Scientific Literature.

American Leadership.—During the first half of the century the progress of zoology in America remained distinctly behind that of Europe. At the beginning of the century the science was farthest developed by the French and English, although Linnæus was a Swede and took his degree in Holland. Under the influence of Von Baer and his monumental treatise on embryology (Ueber Entwicklungsgeschichte der Thiere, 1828), and supported later by the great physiologist, Johannes Müller, whose “Physiologie des Menschen” (1846) forms the basis of modern physiology, the German school forged rapidly ahead and eventually assumed the leadership in zoology, as in several other branches of science.

In the latter half of the century the influence of the German universities dominated in a large measure the zoological investigations in America. The reason for this is partly due to the fact that many of our young zoologists, after finishing their college course, completed their preparation for research by a year or more at a German university. The more mature zoologists, too, looked forward with keen anticipation to spending their summer vacations and sabbatical years in research in a German laboratory or at the famous Naples station in which the German influence was dominant.

With the rise of experimental biology since 1890, however, the American zoologists have shown so high a degree of originality in devising experiments, so much skill in performing them, and such keenness in analyzing the results, that they have assumed the world leadership in several of the special fields into which the science of zoology is now divided.