HARBWICKE'S SCIENCE-GOSSIP. 



125 



of the brain containing cerebro-spinal fluid and 

 cerebral substance — years back in his " Onkologie," 

 and it is consolatory to know that in a work published 

 by him last year, entitled " Descendenz und Patho- 

 logie," he still holds the same belief. 



But there is an analogous instance that sometimes 

 occurs in man. In spina bifida — a congenital mal- 

 formation of the spinal canal — and in that form of it 

 more especially specified as "occulta," with some 

 thickening of the parts, and a greater development of 

 fat and muscle fibre near to the seat of the disease, 

 irritation often gives rise to a most abundant crop of 

 hairs. Mr. Sutton regards the crop of feathers in 

 the case quoted above of the Polish fowl, as arising 

 in much the same way at the first time, but which 

 afterwards became hereditary. 



Leaving this subject now to proceed to Polydacty- 

 lism, or the appearance of supernumerary fingers and 

 toes. Darwin in " Descent of Man," in a note at the 

 bottom of p. 37, says that in vol. ii. p. 12, of his 

 "Variation of Animals and Plants under Domestic- 

 ation," he "attributed, though with much hesita- 



Fig. 61. — Bifurcation of the 

 third digit of a horse. 



Fig. 62. — A similar specimen. 

 Roy. Coll. Surgeons Mus. 



tion, the frequent cases of Polydactylism in men to 

 reversion." And then: "I was partly led to this 

 through Professor Owen's statement, that some of the 

 Ichthyopterygia possess more than five digits, and 

 therefore as I supposed, had retained a primordial 

 condition: but Professor Gegenbaur ('Jenaische 

 Zeitschrift,' B. v. Heft 3, S. 341) disputes Owen's 

 conclusion. On the other hand, according to the 

 opinion lately advanced by Dr. Giinther, on the 

 paddle of Ceratodus, which is provided with articu- 

 lated bony rays on both sides of a central chain of 

 bones, there seems no great difficulty in admitting 

 that six or more digits on one or on both sides 

 might reappear through reversion. I am informed 

 by Dr. Zouteven that there is a case on record of a 

 man having twenty-four fingers and twenty-four toes ! 

 I was chiefly led to the conclusion that the presence 

 of supernumerary digits might be due to reversion, 

 from the fact, that such digits not only are strongly 

 inherited, but as I then believed, had the power of 

 regrowth after amputation, like the normal digits of 

 the lower vertebrata. . . . But at present it is the 

 safest course to give up altogether the idea, that there 

 is any relation between the development of super- 



numerary digits and reversion to some lowly orga- 

 nised progenitor of man." (1883 edition.) Bifur- 

 cation of the axis of a limb has been described by 

 Albrecht in the mud-fish, and by Howes in Cerato- 

 dus, and I published some years back a case of a 

 smooth newt in which a bifid tail occurred. In the 

 figure below of the foot of a horse, preserved by 

 Chauveau, in the Veterinary School of Lyons, a good 

 illustration of a bifurcation of the digits is seen : — " In 

 this case the phalanges attached to the main (third) 

 metacarpal have bifurcated." And Mr. Sutton says, 

 ' ' if these are to be regarded as examples of atavism 

 we shall be obliged to find animals with two tails, 

 any number of spare digits or even limbs." 



Fig. 62 is from a specimen of the right foot of a 

 horse in the Museum of the Royal College of Sur- 

 geons in which a well-developed extra toe is inter- 

 posed between the inner splint bone and the middle 

 toe. " The second row of carpal bones is preserved 

 and exhibits an additional bone. The animal was 

 shod on both toes." This case shows how careful we 

 must be in making any statement without thought, 

 that any given appearance of some abnormality is a 

 reversion. At first sight we have the Hipparion- 

 type. But look close and think — if a case of rever- 

 sion the thumb must be represented by the inner splint- 

 bone, a matter contrary to the dogma laid down so- 

 thetically that those parts which abort last would 

 be the most likely to reappear in successive genera- 

 tions. Then "if we take the pains to compare the 

 specimen with Chauveau's case represented beside it, 

 there remains very little doubt that it is not atavistic 

 but a reduplication of the middle digit — in fact a 

 malformation." 



Mr. Sutton adds a caution which we very often see 

 forgotten, " that we must be careful not to confound 

 physiological types with reversions. For example : 

 an erectile tumour is structurally similar to the comb 

 of a cock, yet no one would venture to suggest that 

 the nsevi which occur so frequently in infants im- 

 mediately over the anterior fontanelle are to be 

 regarded as reversion to a cock's comb." In con- 

 cluding, I do not think there can be one "pebble 

 bead of doubt " — to use an expression of Keats — in 

 the mind of any single impartial reader with reference 

 to the logical conclusiveness of these references of 

 Mr. Sutton. 



The muse of Mrs. Emily Pfeiffer has made hex:- 

 utter in one of the finest sonnets, that evolution is 



"The unknown God on whom we wait: 

 His path the course of our unfolded fate." 



It is evidently the cynosure around which every im- 

 ploration and yearning to Nature to unbosom her 

 secrets, must turn, as round a central pivot of creative 

 might. 



"The teachers of utility would think that they 

 lost their God, if they did not worship Him who 

 gave the ox horns to defend itself. But I hope I 



