Heroes of science

by P. Martin Duncan

Ill health succeeded, but the man worked on at his great book, and even entered the political arena once again at a time of emergency. The winter of 1840-41 was one of illness, and he could no longer work. His friends were dying off, month after month, and when death came to him, he was content. He had been a good son, an excellent father, a loving friend, a true patriot, deserving everything that elevated mankind; and it is admitted by all botanists that he consolidated the science, and gave it a definite natural classification.

De Candolle early in life grasped the truth that plants grow, reproduce, and arrive at maturity, not by accident, but according to natural law, and he soon saw that some parts of plants were of more importance to their well-being and multiplication than others. He was thus a follower of Ray, and he became impressed with the belief that in arranging plants, the resemblances of the most important parts and organs, should be considered before those of the less important. This manner of proceeding he called the natural method. It was founded upon the knowledge of the anatomy of the plants and upon their physiology, and the method required care and research. The artificial method of Linnæus enabled botanists to distinguish plants readily, by examining the most readily examined, and often unimportant, parts of the plant’s flower. It was not a scientific plan, but a ready method. It did not bring one plant into relation with another, showing the common method of growth and reproduction, but simply enabled one plant to be separated and distinguished from another, and this is the least part of botany.

The works of Whewell on the inductive sciences, the article on botany in the “Encyclopædia Britannica,” Pulteney’s “Life of Linnæus,” and that written by Miss Brightwell, of Norwich, and De Candolle’s “Mémoires et souvenirs écrits par lui même” have been freely and largely quoted in these chapters.

CHAPTER VI.
HEROES OF ZOOLOGY.

The nature of the science of zoology—Great zoologists usually botanists also—Aristoteles as a zoologist—Plinius—The long age of no progress—The life of Conrad Gesner—The zoology of Ray and Willughby—Swammerdam—Réaumur—The zoology of Linnæus.

Zoology does for animals what botany does for plants. It is the science which treats of the resemblances and differences of animals, their shapes, and habits, and which explains their position on the earth in different countries, and classifies them. It is inseparably linked on to the study of comparative anatomy and to physiology which treats of the internal structures and the influence which the outside world has upon the living thing. Like botany, the science arose in a simple manner, and men first of all learned to distinguish one animal from another, giving them names. Then their habits were noticed, and some attempt was made to arrange animals by their greater or less resemblances of external shape. The age of the wonderful affected zoology as it did botany, and the intellectual darkness of the Middle Ages prevented progress. The writings of travellers, the discovery of the microscope, and civil and religious liberty, caused the rise of zoology, and the classifications gradually began to include the past or extinct kinds of animals with those which are now existing in a great scheme, which indicates the succession of living things upon the earth.

As a great branch of natural history, it was to be expected that zoology would be studied with botany; and in fact, nearly all the great botanists have been able zoologists, whilst nearly every great zoologist began with botany.

Aristoteles was as great a hero in zoology as he was in botany, and he may be said to have founded the science. Certainly, some of the principal divisions of the animal kingdom were taught by him. He was the first to make an attempt to explain the anatomy of animals, the functions or duties of different parts of their bodies, and to compare them with those of man. He discussed their resemblances and differences with great acuteness. He was especially distinguished as a student of fishes, making a vast number of observations of his own, and collecting those of other writers. After much consideration, Aristoteles wrote upon the distinction between living things and inanimate nature, and we owe him the notion of the distinctions between the genus and the species. He wrote with regard to the species: “An animal species is an assemblage of individual animals, in which not only the whole form of any one resembles the whole form of any other, but each part in any one resembles the corresponding part in any other. Thus, every horse not only resembles every ether horse generally, but the eye or the hoof of every horse resembles the eye or hoof of every other horse. They are, therefore, the same in the character of the individual parts.” “A genus is an assemblage of individuals in which any one bears, upon the whole, an obviously perceptible resemblance to any other. But the corresponding portion in the different species of the same genus, usually differ in colour, form, numbers, size, and proportion.” This is not so clear as the notion of the species, and he extended the term genus to what is now called an assemblage of genera, that is to say, a family, order, or class. He clearly distinguished between white-blooded and red-blooded animals, and was aware of the mysterious connection between the existence of a spinal column, made up of bones, or vertebræ, and red blood. He makes vertebrated, or backboned, animals to take the first place in his scale of classification. Classifying man, viviparous and oviparous quadrupeds, birds, fishes, cetaceous animals (whales), and serpents amongst the red-blooded, Aristoteles put down as white, or no blooded animals, insects, or creatures divided into segments, cuttlefish, with soft substance, rather soft-shelled animals, like lobsters, and hard-shelled creatures such as oysters. He examined, one by one, all the species he could procure, and then classed together as a subordinate generic group all those, which resembling each other in the more important parts of their structure, differed only in size or colour, or in other points of little importance.