The wonders of life : a popular study of biological philosophy / by Ernst Haeckel ; translated by Joseph McCabe.
- Ernst Haeckel
- Date:
- 1905
Licence: In copyright
Credit: The wonders of life : a popular study of biological philosophy / by Ernst Haeckel ; translated by Joseph McCabe. Source: Wellcome Collection.
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![regard the chemical processes in the gan- glionic cells of the cortex as the real factors of knowledge and all other psychic action. The chemistry of the neuroplasm deter- mines the vital function of the phronema. The same must be said of its most perfect and enigmatic function, consciousness. Although this greatest wonder of life is only directly accessible by the introspective method, or by the mirroring of knowledge in knowledge, nevertheless the use of the comparative method in psychology leads us to believe confidently that the lofty self- consciousness of man differs only in degree, and not in kind, from that of the ape, dog, horse, and other higher mammals. Our monistic conception of the nature and seat of the soul is strongly confirmed by psychiatry, or the science of mental disease. As an old medical maxim runs, Patholoi^ia f>hysiologiam ilius/rat—the science of disease throws light on the sound organism. This maxim is especially applicable to mental diseases, for they can all be traced to modifications of parts of the brain which discharge definite functions in the normal state. The localisation of the disease in a definite part of the phro- nema diminishes or extinguishes the normal mental function wliich is discharged by this section. Thus disease of the speech- centre, in the third frontal convolution, destroys the power of speech ; the destruc- tion of the visual region (in the occipital convolutions) does away with the power of sight ; the lesion of the temporal convolu- tions destroys hearing. Nature herself here conducts delicate experiments which the physiologist could only accomplish very imperfectly or not at all. And although we have in this way only succeeded as yet in showing the functional dependence of a certain part of the mental functions on the respective parts of the cerebrum, no unpre- judiced physician doubts to-day that it is equally true of the other parts. Each special mental activity is determined by the normal constitution of the relevant part of the brain, a section of the phro- nema. Very striking examples of this are afforded in the case of idiots and micro- cephali, the unfortunate beings whose cerebrum is more or less stunted, and who have accordingly to remain throughout life at a low stage of mental capacity. These poor creatures would be in a very pitiable condition if they had a clear consciousness of it, but that is not the case. They are like vertebrates from which the cerebrum has been partly or wholly removed in the laboratory. These may live for a long time, be artificially fed, and e.xecute auto- matic or reflex (and in part purposive) motions, without our perceiving a trace of consciousness, reason, or other mental function in them. The embryology of the child-soul has been known in a general way for thousands of years, and has been an object of keen interest to all observant parents and teachers ; but it was not until about twenty years ago that a strictly scientific study was made of this remarkable and important phenomenon. In 1884 Kussmaul published his Untersuchimgeti iiber das Seelenleben des 7ieugeborenen Menscheji, and in 1822 W. Preyer published his Mind of the Child [English translation ; Dr. J. Sully has several works on the same subject]. From the careful manuals which these and other observers have published, it is clear that the new-born infant not only has no reason or consciousness, but is also deaf, and only slowly developes its sense and thought- centres. It is only by gradual contact with the outer world that these functions suc- cessively appear, such as speech, laughing, etc.; later still come the power of associa- tion, the forming of concepts and words, etc. Recent anatomic observations quite accord with these physiological facts. Taken together, they convince us that the phronema is undeveloped in the new-born infant; and so we can no more speak in this case of a “seat of the soul” than of a “human spirit” as a centre of thought, knowledge, and consciousness. Hence the destruction of abnormal new-born infants—as the Spartans practised it, for instance, in selecting the bravest—cannot rationally be classed as “ murder,” as is done in even modern legal works. We ought rather to look upon it as a practice of advantage both to the infants destroyed and to the community. As the whole course of embryology is, according to our bioge- netic law, an abbreviated repetition of the history of the race, we must say the same of psychogenesis, or the development ot the “soul” and its organ—the phronema. Comparative psychology comes next in importance to embryology as a means of studying the ancestral history of the soul. Within the ranks of the vertebrates we find to-day a long series of evolutionary stages which reach up from the lowest acrania and cyclostoma to the fishes and dipneusta, from these to the amphibia, and from these again to the amniota. Among the latter, moreover, the various orders of reptiles](https://iiif.wellcomecollection.org/image/b28075754_0026.jp2/full/800%2C/0/default.jpg)
