io8 



NATURE 



{May 23, 1878 



scribed, since no natural instance of the former kind is known 

 up. to the present, and since the latter kind cannot be recognised 

 as compound fluorescence by any optical means. 



THE ARTIFICIAL TRANSFORMATION OF 

 THE ALPINE SALAMANDER 



THE success of Madame von Chauvin in producing the de- 

 velopment of Amblystoma from the Mexican axolotl by 

 gradually accustoming it to live in air, induced her to attempt a 

 very interesting interference with the life-history of the black or 

 Alpine salamander, Salamandra aira. This is an ovoviviparous 

 species, and although its young possess large gills while within 

 the body of the mother, they are born to commence a land 

 life immediately ; while other species of salamander, especially 

 the spotted one, S. maculata, found in adjacent districts to the 

 subjcc: of inquiry, bring forth their young with gills, and they 

 pass a considerable period in water before taking to land. The 

 problem which it was desired to solve was, whether the young 

 of the black salamander, taken from the mother before the 

 normal time of birth, and placed in water under favourable 

 conditions, could become adapted to an aquatic life. It is in- 

 teresting to note that while only two eggs out of many come 

 to full development in the black salamander, forty or fifty 

 develop in the spotted one ; yet individuals of the two species 

 are about equally numerous in their respective localities. This 

 shows the value of the avoidance of life in water with its atten- 

 dant risks, though probably the diminution of terrestrial enemies 

 in the more elevated localities frequented by the black salaman- 

 der is a considerable influence in its favour. 



Madame von Chauvin's researches are detailed in a recent 

 number (vol. xxix. p. 324) of the Zeitschrift fiir wissenschaft- 

 liche Zoologie. They commenced on July 30, 1875, '^ith twenty- 

 three larvse taken in various stages of development ; eight were 

 about I \ centimetres long, twelve were from i,\ to 5 centimetres, 

 and had almost completed their metamorphosis into land sala- 

 manders. One was a little less developed, 4*3 centimetres long, 

 the gills and skin-glands were less perfect, and the skin was very 

 transparent and unwrinkled. This larva, unlike the rest, ap- 

 peared at ease when placed in water, and made no attempts to 

 get out of it. The next problem was to feed the little creature, 

 and the first attempt was made by supplying a number of various 

 minute water insects ; but although it evinced some desire to catch 

 them, the insects were able to escape capture, while the larva 

 seemed to become annoyed by their presence. Later on, a 

 minute earthworm being offered, it was taken and swallowed, 

 and the problem was solved. A daily supply of the same food 

 was thenceforth taken by the young salamander. 



The gills which the creature possessed in the oviduct appeared 

 from the first little adapted for life in water ; they were of so 

 thin a texture that they could hardly be expected to endure ex- 

 posure and motion, while their great extent evidendy hampered 

 the movement of the animal. Consequently the gills first became 

 pale and bloodless, then shrank, and on the third day were 

 entirely thrown off, down to the very base. But on the same 

 day on the right side, a day later on the left, minute buds 

 appeared, three on each side, which gradually enlarged into ball- 

 like protuberances ; from these, after three weeks, gill- fringes were 

 put forth, which finally numbered nine on the first pair of gills. 

 The fringes were mostly arranged along the external border of the 

 gills, and they assumed abrown-spotted character, while the blood- 

 circulation through them became plainly perceptible. They were 

 very much less extensive than the previous set of gills, but 

 appeared to perform the work of respiration perfectly ; the 

 creature remained completely beneath the surface of the water, 

 without ever coming up to breathe air. While the new gills 

 were being developed the larva remained at rest as if dead, only 

 eating the earthworms when they were offered. 



When the gills had attained a length of 2*2 mm. the larva 

 became lively, and concurrent with this was the completion of 

 another transformation. The delicate and transparent swimming 

 membrane of the tail was lost, and replaced by a less transparent 

 and stouter one, of greater dimensions. The creature now seemed 

 to enjoy life much more than before, exhibiting greater interest 

 in its living food, with which it would play before swallowing it. 

 Finally, after six weeks' residence in the water, a skin-shedding 

 commenced, the skin coming away piecemeal for a fortnight. 



The larva continued to grow satisfactorily without undergoing 

 further modification, until it had been fourteen weeks in the 

 water, having attained a length of 6 centimetres. The gills then 



began to shrink, and the tail to assume a rounder form, ahd in 

 three days the skin was shed, revealing the normal black and 

 wrinkled skin of the land salamander. In nine days from their 

 first shrinking the gills were nearly absorbed, only little stumps 

 remaining. At last it crawled out of the water, and on the four- 

 teenth day the gills were complttely absorbed and the gill clefts 

 closed. The remaining larger larvte of this experiment lost 

 their primary gills less satisfactorily and in a greater length oi 

 time. New gills commenced to bud, but the creatures were 

 gradually destroyed by fungus-growths attacking various parts of 

 their skin. The fact that they were altogether more advanced 

 in their metamorphosis rendered them unable to adapt themselves 

 quickly to their new conditions. 



A second series of researches on the Alpine salamander was 

 carried on in the summer of 1876, when a large number 0* 

 individuals were collected at Thusis, at the confluence of the' 

 Rhine and the Nolla. The animals were collected thirteen days 

 earlier than in the previous year, so that the development of the 

 young was not so forward. Thirty-three larvee were taken from 

 the oviducts, eight of which were from 8 mm. to ^o mm. long, 

 two 12 mm., and twenty-three from 35 mm. to 40mm. All had 

 their skin still transparent and their gills not yet of full size. 

 After twelve of them had refused insects, minute earthworms 

 were administered to them, but they did not eat them till after 

 some hours. Two larvre, immediately after being taken out of 

 the mother and placed in the water, fastened respectively on the 

 head and tail of a worm that was wriggling at the bottorn of the 

 water. Their diflSculty was solved by cutting the worm in two, 

 and each obtained half. This method of immediate feeding was 

 thereafter successfully adopted, and it appeared to develop a 

 good appetite in the larvie. 



One noteworthy circumstance in regard to these creatures was 

 that, at a time when they would normally be still within the 

 body of the parent, they were as active and as eager for food as 

 new-bom larvK of the spotted salamander. They were often so 

 greedy for their prey that they seized hold of the limb of a 

 neighbour of their own kind instead of the desired worm. But 

 nevertheless these creatures did not develop in the desired direc- 

 tion, the gills did not begin to shrink quickly, and when they 

 did they were not got rid of as a whole, but the dead portions, 

 remaining attached to the body, became the seat of fungus 

 growth, which speedily increased and spread so as to kill the 

 animal. Thus none of ihe subjects of investigation really became 

 adapted to their life in water. In two cases it was attempted to 

 succeed artificially by cutting off the gills nearly at the base ; one 

 died soon, owing to fungus growths, the other quickly became a 

 land salamander. 



Experiments like the foregoing have the highest interest, for 

 they mark out for us the actual path of adaptation to changed 

 physical conditions. It appears highly probable that the spotted 

 and the Alpine salamanders were at no very distant period of 

 time one species, and that as physical conditions became changed 

 one variety became more and more adapted to more elevated 

 and rocky habitats, where water for the early life of the larvte 

 was not commonly to be met with. Thus gradually the birth of 

 the young was postponed, and they became non-aquatic ; con- 

 currently fewer and fewer of the many eggs were developed. The 

 spotted salamander, meanwhile, became more and more spe- 

 cialised to inhabit the lowland districts. Such cases as Madame 

 von Chauvin's, if they remained single instances, would suffice to 

 establish natural selection as a vera causa of the mutation of 



species. 



G. T. Bettany 



UNIVERSITY AND EDUCATIONAL 

 INTELLIGENCE 



Bristol.— The Council of University College have resolved 

 to found an Engineering School in connection with the scientific 

 and technical courses of instruction already established. It is 

 announced that the scheme will meet with the support of the 

 local engineering firms. In accordance with this scheme the 

 lectureships in Mathematics and Experimental Physics have been 

 elevated into professorships, and the present holders of the 

 lectureships, J. F. Main, M.A., D.Sc, and S. P. Thompson, 

 B.Sc, B.A., have been elected to the new chairs. 



It is stated that the new buildings of the College will be 

 commenced at once, an excellent site having been secured several 

 months ago. The number of students attending the present 

 term exhibits a considerable increase upon the corresponding 

 term of the preceding year. 



