Page:Popular Science Monthly Volume 7.djvu/769

 

PROGRESS OF NATURAL HISTORY.

A comprehensive German work on natural history, entitled a "Hand-Book of Zoölogy," by Prof. Carus, assisted by Prof. Gerstäcker, has just been completed. Its publication by Engelmann, of Leipsic, was begun in 1863, and the last volume has been recently issued. The work is reviewed in Nature by Prof. E. Ray Lancaster (editor of Haeckel's great work, soon to be issued), and of the general merits of the Hand-book he speaks as follows:

"As the latest complete systematic treatise on the animal kingdom, and one executed with the exercise of most conscientious care, and a very exceptional knowledge of the vast variety of zoölogical publications which now almost daily issue from the press, this work Is one which is sure to render eminent service to all zoölogists. We can speak to the usefulness of the earlier volume, from an experience of some years, and there is every reason to believe that the one just completed will be found as efficient."

Having pointed out, with some detail, the scope and characteristics of Prof. Carus's treatise. Dr. Lancaster proceeds to estimate it with more special reference to the later advances of biological theory, and his remarks upon this subject are so opportune and instructive, that we quote them at length. They afford an excellent illustration of the broad applicability and practical bearing of these modern doctrines in relation to life, doctrines which are still characterized by many as "unfruitful speculations."

Prof. Carus suffers in this book as in his 'History of Zoology,' from the unphllosophic conception of the scope and tendencies of that division of biology which its early history has forced upon modern science. In England our newest and most conservative university continues to draw a broad distinction between what is called comparative anatomy and what is called zoölogy. By some accident zoölogy Is the term which has become connected with the special work of arranging specimens and naming species which is carried on in great museums, and which has gone on in museums since the days when 'objects of natural history,' and other curiosities, first attracted serious attention in the sixteenth century. Accordingly, zoology, in this limited sense, has taken the direction indicated by the requirements of the curators of museums, and is supposed to consist in the study of animals not as they are in toto. But as they are for the purposes of the species-maker and collector. In this limited zoology, external characters, or the characters of easily-preserved parts which on account of their conspicuousness or durability are valuable for the ready discrimination of the various specific forms, have acquired a first place in consideration to which their real significance as evidence of affinity or separation does not entitle them.

"From time to time the limited zoölogists have adopted or accepted from the comparative anatomists hints or conclusions, and have worked them into their schemes of classification. But it does seem to be time in these days, when pretty nearly all persons are agreed that the most natural classification of the animal kingdom is that which is the nearest expression of the animal pedigree, that systematic works on zoölogy should be emancipated from the hereditary tendencies of the old treatises, and should present to us the classes and orders of the animal kingdom defined not by the enumeration of easily-recognized 'marks,' but by reference to the deeper and more thorough-going characteristics which Indicate blood relationships. We have to note in the 'Handbuch' the not unfrequent citation of superficial and insignificant characteristics In the brief diagnoses of taxonomic groups, which seems in so excellent a work to be due to a purposeless survival of the features of a moribund zoölogy that would know nothing of 'insldes,' and still less of the doctrine of filiation. For instance, the very first thing which we are told of the vertebrata, in the short diagnosis of the group, is, that they are 'animals with laterally symmetrical, elongated, externally unsegmented bodies;' of the fishes, that they have the 'skin covered with scales or plates, seldom naked; 'of the mollusca, that they have a 'laterally symmetrical, compressed body devoid of segmentation, often inclosed in a single (generally spirally-twisted) or double calcareous shell.'

"It would be unjust to suggest that Prof. Carus, who long ago did so much to establish zoölogical classification on an anatomical basis, is not fully alive to the necessity, at the present day, of taking the wide biological view of animal morphology; but cer-