RETROSPECT AND PROSPECT. RECENT TENDENCIES IN BIOLOGY
When one views the progress of biology in retrospect, the broad truth stands out that there has been a continuity of development in biological thought and interpretation. The new proceeds out of the old, but is genetically related to it. A good illustration of this is seen in the modified sense in which the theories of epigenesis and pre-formation have been retained in the biological philosophy of the nineteenth century. The same kind of question that divided the philosophers of the seventeenth and eighteenth centuries has remained to vex those of the nineteenth; and, although both processes have assumed a different aspect in the light of germinal continuity, the theorists of the last part of the nineteenth century were divided in their outlook upon biological processes into those of the epigenetic school and those who are persuaded of a pre-organization in the germinal elements of organisms. Leading biological questions were warmly discussed from these different points of view.
In its general character the progress of natural science has been, and still is, a crusade against superstition; and it may be remarked in passing that "the nature of superstition consists in a gross misunderstanding of the causes of natural phenomena." The struggle has been more marked in biology than in other departments of science because biology involves the consideration of living organisms and undertakes to establish the same basis for thinking about the organization of the human body as about the rest of the animal series.
The first triumph of the scientific method was the overthrow of authority as a means of ascertaining truth and substituting therefor the method of observation and experiment. This carries us back to the days of Vesalius and Harvey, before the framework of biology was reared. But the scientific method, once established, led on gradually to a belief in the constancy of nature and in the prevalence of universal laws in the production of all phenomena. In its progress biology has exhibited three phases which more or less overlap: The first was the descriptive phase, in which the obvious features of animals and plants were merely described; the descriptive was supplemented by the comparative method; this in due course by the experimental method, or the study of the processes that take place in organisms. Thus, description, comparison, and experiment represent the great phases of biological development.
The Notable Books of Biology and their Authors.—The progress of biology has been owing to the efforts of men of very human qualities, yet each with some special distinguishing feature of eminence. Certain of their publications are the mile-stones of the way. It may be worth while, therefore, in a brief recapitulation to name the books of widest general influence in the progress of biology. Only those publications will be mentioned that have formed the starting-point of some new movement, or have laid the foundation of some new theory.
Beginning with the revival of learning, the books of Vesalius, De Corporis Humani Fabrica (1543), and Harvey, De Motu Cordis et Sanguinis (1628), laid the foundations of scientific method in biology.
The pioneer researches of Malpighi on the minute anatomy of plants and animals, and on the development of the chick, best represent the progress of investigation between Harvey and Linnæus. The three contributions referred to are those on the Anatomy of Plants (Anatome Plantarum, 1675-1679); on the Anatomy of the Silkworm (De Bombyce, 1669); and on the Development of the Chick (De Formatione Pulli in Ovo and De Ovo Incubato, both 1672).
We then pass to the Systema Naturæ (twelve editions, 1735-1768) of Linnæus, a work that had such wide influence in stimulating activity in systematic botany and zoölogy.
Wolff's Theoria Generationis, 1759, and his De Formatione Intestinorum, 1764, especially the latter, were pieces of observation marking the highest level of investigation of development prior to that of Pander and Von Baer.