the Midwife Toad. 181 
males immediately after they bad been fertilized, and placing 
them in water drawn from the little pond in which they 
would have ultimately hatched had they been left to the care 
of the parent; but development stopped on the fifth or sixth 
day, at the period when the embryo produces its external gills. 
I may add that the eggs so treated did not show the extra- 
ordinary “‘ Aufquellen der Gallerthiille, genau wie dies bei 
anderen Anuren-Hiern der Fall ist ” (1, p. 74). 
I fully expected some reason would be forthcoming on the 
part of Kammerer to explain the failure of my experiment, 
and so it was; but I should never have thought him capable 
of making a new statement so contrary to the plain wording 
of the sentence quoted above, which is to the effect that, after 
lying thirteen to fifteen days in water 3 cm. deep, no 
manipulations being mentioned, the larvee (all or most of 
them, as anyone would understand) swarmed out (“ senwiarm- 
ten aus”) of the egg-capsules. I was therefore, I think, 
fully justified in saying * “Il en serait autrement des Alytes 
de Westphalie, appartenant pourtant 4 la méme espéce, puis- 
que Kammerer, opérant avec ceux-ci, ne semble avoir aucune 
difficulté & contrarier ainsi l’ordre de la nature.” 
Now this is what Kammerer, replying to my criticism, 
tells us (5, p. 260) really happened on that occasion :— 
* Junge A/ytes-Kier befinden sich, unter Wasser liegend, 
an sich schon nicht unter ‘natiirlichen’? Bedingungen, und, 
um diese zu kompensiren bedarf es ebenso ‘ unnatiirlicher ” 
Gegenbedingungen.....in peinlicher Sterilhaltung des 
Laiches: in ausgekochtem, dann kiinstlich durchliiftetem 
Wasser. ‘Trotzdem dringen noch Schimmelkeime ein, und 
jedes befallene Ei muss sorgfiltig entfernt werden. Bei 
Kinhaltung dieser Vorsichtsmassregeln mussten immerhin 
zahlreichere Hiballen abgestorben in den Kiibel wandern, als 
Herr Boulenger wohl sie zu seinen Versuchen verwendet hat, 
bis ich endlich an einigen wenigen Hier einiger weniger 
Hierballen mit der submersen Hutwicklung Gliick hatte.” 
Why, it may be asked, was all this not mentioned at first, 
instead of letting the reader believe that the embryos under- 
went the whole of their development without any intervention 
on the part of the experimentator. 
From this sample of the levity with which Kammerer 
relates his experiments, is it surprising if some of his state- 
ments should be challenged by those who, like myself, do not 
place implicit confidence in them ? 
* Bull. Ac. Belg. 1912, p. 579. 
