essays in systematic evolution that appeared. To the explanation of the relations discovered by this research I applied the Lamarckian doctrine of use (or motion) and disuse, and added to that doctrine. the effects on animal movements which result from the mental state called effort, in 1871.1 This constitutes the earliest attempt, so far as I am aware, to demonstrate the influence of mind on organic evolution. Since that period my discoveries in the phylogeny of the Vertebrata through paleontologic investigations in North America have enabled me to present rational explanations for the origin and evolution of a number of particular groups. Important contributions to corresponding histories of the Mollusca have been made by Hyatt, Dall, Jackson, and Beecher. Many other contributions, into which the paleontologic evidence does not enter, have also been made by various authors in Europe and America.

2

The authors quoted up to this point had all assumed that the progress of evolution depends on the inheritance by the offspring of new characters acquired by the parent, and had believed that such is the fact in ordinary experience. In 1883, Weismann, in an essay on heredity, announced the opinion that characters acquired by the body could not be transmitted to the reproductive cells, and could not therefore be inherited. This doctrine rests on the relation of the germ-cells to those of the rest of the body, which is expressed in the following language of his predecessor Jaeger: "Through a great series of generations the germinal protoplasm retains its specific properties, dividing in every reproduction into an ontogenetic portion and a phylogenetic portion, which is reserved to form the repro

"The Method of Creation," Proceeds. Amer. Philos. Soc., 1871, December; Origin of the Fittest, 1887, p. 173.

2 The Origin of the Hard Parts of Mammalia," American Journal of Morphology, 1889, p. 137.

3" The Genesis of the Arietida," Memoirs Mus. Compar. Zoology, Cambridge, Mass., 1889, XVI., No. 3.

Dall, W. H., "The Hinge of Pelecypods and Its Development," Amer. Jour. Sci. Arts, 1889, XXXVIII., p. 445.

5 Jackson, R. T., "Phylogeny of the Pelecy poda, the Aviculidæ, and Their Allies,', Memoirs Boston Soc. Nat. Hist., 1890, IV., p. 277.

6 American Journ. Sci. Arts, 1893.

ductive material of the mature offspring. This reservation of the phylogenetic material I described as the continuity of the germprotoplasm. . . . Encapsuled in the ontogenetic material the phylogenetic protoplasm is sheltered from external influences, and retains. its specific and embryonic characters." In other words, the reproductive cells are removed from the influence of those stimuli which affect and effect growth in the cells of the other parts of the body, so that no character acquired by the rest of the body can be inherited. The bearing of this theory on evolution is thus stated by Weismann: "The origin of hereditary individual variations cannot indeed be found in the higher organisms, the metazoa and metaphyta, but is to be sought for in the lowest, the unicellular." "The formation of new species, which among the lower protozoa could be achieved without amphigony (sexual union), could only be attained by means of this process in the metazoa and metaphyta. It was only in this way that hereditary individual differences could arise and persist." In other words, variation in organic beings above the unicellular forms, has been and is, introduced only by sexual reproduction.

The conclusions of Weismann were derived principally from embryologic research, and his disciples have been chiefly recruited from embryologists. These conclusions have been supported by extensive and exhaustive investigations, which have added greatly to our knowledge of the subject. In order to account for the appearance of characters in the embryonic succession, through influences confined to the germ-plasma, Weismann invented a theory which requires the presence of distinct molecular aggregates within it, which represent the potentialities or causes. To these he has given the names of ids, idants, determinants, etc.

Weismann has, however, subsequently modified his views to a considerable extent. He has always admitted the doctrine of Lamarck to be applicable to the evolution of the types of unicellular organisms. His experiments on the effect of temperature on the production of changes of color in butterflies, showed that such

1 Essays, p. 296. For a complete account of Weismann's views, see The GermPlasm, 1893.

changes were not only effected, but were sometimes inherited. This he endeavors to explain as follows. "Many climatic variations may be due wholly or in part, to the simultaneous variation of corresponding determinants in some parts of the soma and in the germplasm of the reproductive cells." This is an admission of the doctrine which in 1890 I called Diplogenesis. It appears to have been first propounded by Galton in 1875.

From what has preceded, two distinct lines of thought explanatory of the fact of organic evolution may be discerned. In one of these the variations of organisms which constitute progressive and regressive evolution appear fortuitously, and those which are beneficial survive by natural selection, while those which are not so, disappear. Characters both beneficial and useless or harmless, which are acquired by the adult organism, are not transmitted to the young, so that no education in habit or structure acquired by the adult, has any influence in altering the course of evolution. This is the doctrine of Preformation. From this point of view the cause of the variation of organisms has yet to be discovered.

The other point of view sees in variation the direct result of stimuli from within and without the organism; and holds that evolution consists of the inheritance of such variations and the survival of the fit through natural selection. This is the doctrine of Epigenesis. To this I would add that in so far as sensations or states of consciousness are present, they constitute a factor in the process, since they enable an organism to modify or change its stimuli. The position of each of these schools on each of the questions to which. reference has been made, may be placed in opposition as follows:

1. Variations appear in definite directions.

2. Variations are caused by the interaction of the organic being and its environment.

3. Acquired variations may be inherited.

I. Variations are promiscuous or multifarious.

2. Variations are "congenital" or are caused by mingling of male and female germ-plasmas.

3. Acquired variations cannot be inherited.

1 The Germ-Plasm, Contemporary Science Series, 1893, p. 406. 2 American Naturalist, December, 1889; published in 1890.

4. Variations survive directly as they are adapted to changing environments. (Natural selection.)

5. Movements of the organism are caused or directed by sensation and other conscious states.

6. Habitual movements are derived from conscious experience.

7. The rational mind is developed by experience, through memory and classification.

4. Variations survive directly as they are adapted to changing environments. (Natural selection.)

5. Movements of organism are not caused by sensation or conscious states, but are a survival through natural selection from multifarious movements.

6. Habitual movements are produced by natural selection.

7. The rational mind is developed by natural selection from multifarious mental activities.

It is not my object to present the available evidence on both sides of each of the questions above enumerated, for I must here be satisfied with having formulated the problem. I shall treat the subject at full length in a forthcoming book, in which I propose to submit certain facts, in support of the doctrines contained in the left-hand column of the above table. My aim will be to show in the first place, that variations of character are the effect of physical causes; and second, that such variations are inherited. The facts adduced in support of these propositions will be necessarily principally drawn from my own studies in the anatomy, ontology, and paleontology of the Vertebrata. It will be my aim, moreover, to co ordinate the facts of evolution with those of systematic biology, so that the result may be as clearly presented as possible. The failure to do this by the founders of evolutionary doctrine has given their work a lack of precision, which has been felt by systematic biologists. The detailed application of the principles of Lamarck and Darwin has been the work of their successors, and has necessarily thrown much new light on the principles themselves. We have at present ampler means than ever to consider the validity of the general propositions on which the doctrine of evolution rests.

PHILADELPHIA, PA.

E. D. COPE.

THE SCIENCE OF MENTATION

AND

SOME NEW GENERAL METHODS OF PSYCHOLOGIC

BY

RESEARCH.

Y mentation I mean the totality of the conscious and subconscious adaptive functionings of a living organism.

Bio-psychology is that department of the science of mentation which studies organic structures and their environments in order to determine the relations which exist between these and the menta

tions which accompany them. It studies such structures and environments which nature provides, and so far its method is that of observation; but it also artificially varies organic structures and environments, and to that extent its method is experimental. As experimental bio-psychology, it varies structure to determine function; and its scope includes three great sciences :

scien

1. Biologic Psychology, which is that department of the science of mentation wherein our knowledge of mind is obtained by a tific study of (A) organisms and their anatomical and molecular structures as exhibited by nature, and as varied by definite experimental conditions artificially produced; and by a study of (B) the cosmic environment of such organisms as exhibited in nature, and as varied by definite experimental conditions; and also by a study of (C) the mentations of organisms as exhibited in nature in envi ronments that have not been artificially disturbed, and as exhibited under the definite experimental conditions of organism and environment before mentioned. In other words, this science studies the individual organism as one factor in producing mentation of a defi