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SUMMARY OF CURRENT RESEARCHES RELATING TO 
daylight, but are only somewhat more developed than in the adult 
animal. Recapitulation does not therefore occur except when the ex- 
ternal condition to which the ancestral structure was adapted continues 
to act at an early period of life.” 
The article is a very interesting one, but we cannot silence the wish 
that expert embryologists, such as the writer, would, in writing on re- 
capitulation, bring the discussion to a more definite focus. Is this 
recapitulation-doctrine, with its long pedigree going back far beyond 
von Baer, who was as much its critic as its exponent, and with its pro- 
longed and surely not wholly disastrous influence on embryology, an 
entirely mistaken interpretation ? If not, what precisely is wrong with 
it, and what restatement may for a time fill its place ? If yes, do we 
not require a franker confession of ignorance as to the meaning of such 
structures as the gill-slits of Mammals, and a more strenuous physio- 
logical embryology ? 
Regeneration of Organs in Amphibia.* — Prof. W. Kochs has ex- 
perimented with tadpoles of Rana fusca and Bombinator igneus , and also 
with salamanders and newts. He found a platinum needle and galvanic 
cautery the most serviceable instrument. Immediately after the operation 
the tadpoles swam about as if nothing had happened, and on the second 
day they ate white bread and frog-flesh as usual. 
When an eye was wholly destroyed, no hint of regeneration could be 
observed, even after three months. Kochs generalises this result in the 
conclusion that regeneration of an organ occurs only when a portion of 
the organ is left. 
The author cites some interesting historical notes from a paper by 
Y. Colucci which seems hardly to have received the attention it deserves. 
Thus Bonnet and Blumenbach proved the regeneration of the newt’s eye 
when a remnant was left in connection with the optic nerve ; Philip- 
peaux (1880) showed that no regeneration occurred (in 40 cases) when 
no remnant was left ; Colucci (1891) has priority over Gustav Wolff 
and Erik Muller in demonstrating the regeneration of an extirpated lens 
from a centre of formation situated in the anterior border of the iris. 
The experiments which Kochs himself made on this interesting 
question of lens-regeneration lead him to the suggestion that the new 
lens may arise from epidermic cells brought into the interior of the eye 
by the operation. He thinks it unlikely that the iris could remain quite 
uninjured by the operation, as Erik Muller maintains. This result is 
certain, that in tadpoles the lens is regenerated as it is in newts ; but 
a secure conclusion as to the precise formative tissue of the new lens is 
still to seek. 
In general, Kochs concludes that in regeneration a restitutio in integ- 
rum never occurs, the regenerated part being always smaller ; that in 
forms other than larvte there is during regeneration a hypertrophy of the 
part which compensates for that which has been removed ; that repro- 
ductive power is greater and more rapid when only small parts of the 
extremities are amputated. The appearance of extra parts is more 
probable, as Barfurth has shown, the nearer the amputation is to the 
proximal end of the appendage. 
* Arch. f. Mikr. Anat., xlix. (1897) pp. 441-61 (1 pi. and 3 figs.). 
