Walter Holbrook Gaskell

“ The great law of recapitulation, which asserts that the past history of the race is indicated more or less in the development of each individual, a law which of late years has fallen somewhat into disrepute, owing especially to the difficulty of interpreting the embryological history of the vertebrate, is triumphantly vindicated by the theory put forward in this book. ”

“ It is, to my mind, improbable that the Mauthnerian fibres pass out directly as motor fibres to the muscles of the tail-fin; it is more likely that they are conducting paths between the equilibration-mechanism in connection with the VIIIth nerve and the spinal centres for the movements of the tail. Similarly, with respect to the arthropod, it is difficult to believe that the motor fibres for the tail-muscles arise in the brain-region. ”

“ In this way we can trace without a break, always following out the same law, the evolution of man from the mammal, the mammal from the reptile, the reptile from the amphibian, the amphibian from the fish, the fish from the arthropod, the arthropod from the annelid, and we may be hopeful that the same law will enable us to arrange in orderly sequence all the groups in the animal kingdom. ”

“ It has been found that the serum of the blood of another animal, when injected in sufficient quantity into a rabbit, will cause such a change in the serum of that rabbit's blood that when it is added to the serum of the other animal a copious precipitate is formed, although the serum of normal rabbit's blood when mixed with that of another animal will cause no precipitate whatever. ”

“ It is simply that in one place of the collar-region the piece of skin containing the dorsal nerve of the animal, owing to the formation of the collar, is folded, and thus forms just at this region a short tube. My theory explains in a natural manner every portion of the elaborate and complicated tube of the vertebrate central nervous system. In the Balanoglossus theory the evolution of the vertebrate tube in all its details from this collar-fold is simple guesswork, without any reasonable standpoint. ”

“ If, then, a higher group is to arise from a lower, it must arise from the generalized members of that lower group, in other words, from the lowest members or those nearly akin to the next lower group. ”

“ In all cases, upward progress is associated with a development of the central nervous system.
The law for the whole animal kingdom is the same as for the individual. "Success in this world depends upon brains." ”

“ The first of these is the significance of the giant nerve-cells and giant nerve-fibres so characteristic of the brain-region of the lower vertebrates. In most fishes two very large cells are most conspicuous objects in any transverse section of the medulla oblongata at the level of entrance of the auditory nerves. Each of these cells gives off a number of processes, some of which pass in the direction of the auditory nerves and one very large axis-cylinder process which forms a giant-fibre, known by the name of a Mauthnerian fibre. ”

“ A few fibres are also found laterally, and slightly dorsally, to the grey matter. These giant-fibres pass down the spinal cord right to the anal region; their ultimate destination is unknown. Mayer considers that in the first part of their course they correspond to those tracts of fibres known as the "posterior longitudinal bundles" in other vertebrates. I imagine, therefore, that the spinal part of their course represents the two antero-lateral descending tracts. The second group of giant-cells, which appears to have some connection with the auditory nerves, may represent "Deiter's nucleus." ”

“ Further, if that animal is closely related a precipitate will be formed nearly as copious as with the original serum, if more distantly related a cloudiness will occur rather than a precipitate, and if the relationship is still more distant the mixture of the two sera will remain absolutely clear. Thus this test demonstrates the close relationship of man to the anthropoid apes and his more distant relationship to monkeys in general. ”

“ In Palæontology there is nothing, only an assumption that in the Cambrian and Lower Silurian times a whole series of animals were evolved between Balanoglossus and the earliest armoured fishes, which have left no trace, although they were able to hold their own against the dominant Palæostracan race. ”

“ The Mauthnerian fibres are known to give origin to certain fibres which supply the ventral roots of the last three spinal nerves, so that their terminal branches serve, in all probability, for the innervation of the muscles of the tail-fin. ”

“ The muscular system requires further investigation, not so much the different systems of the striated voluntary musculature—for these have been for the most part compared in the two groups of animals in previous chapters—as the involuntary unstriped musculature, about which no word has been said. ”

“ The cells which give origin to all these large, long fibres are situated in or in front of the prosomatic region of the brain, similarly to the giant-cells, which give rise to the corresponding Müllerian fibres of Ammocœtes. ”

“ I can only conclude that both they and Amphioxus arose late, after the vertebrate stock had become well established, so that in their degenerated condition they give indications of their vertebrate ancestry and not of their more remote arthropod ancestry. ”

“ It discards the old picture of a genealogical tree with main branches arising at different heights, these again branching and branching into smaller and smaller twigs, and substitutes instead the picture of the ribs of a fan, every rib running independently of every other, each group represented by a rib reaching its highest development on the circumference of the fan and coming nearer and nearer to a common point at the handle of the fan. ”