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The Mexican Axolotl and its 
[June, 
VII. THE MEXICAN AXOLOTL AND ITS 
SUSCEPTIBILITY TO TRANSFORMATIONS. 
S HE prolonged researches of Miss Marie Von Chauvin 
on the biological relations of the Amphibians have 
led to most interesting results concerning the trans- 
formability of the Mexican axolotl. The observations pub- 
lished by this lady ten years ago proved that under certain 
conditions, and by certain treatment, it is possible to convert 
the aquatic axolotl, breathing b}^ means of gills, into the 
terrestrial Amblystoma, which breathes by means of lungs. 
Individual differences, however, came to light which de- 
manded further enquiry. This has accordingly been carried 
out, and Miss von Chauvin now lays her conclusions before 
the public in the “ Zeitschrift fur Wissenschaftliche 
Zoologie.” 
It was soon found that younger specimens could be more 
easily transformed than older ones, but even among indivi- 
duals of the same age great differences came to light, 
depending upon the manner of treatment. Thus axolotls 
can be more readily converted into Amblystomas if they are 
kept in water containing little air, and are thus compelled to 
come more frequently to the surface and to breathe with 
their lungs. Others, kept in richly aerated water, obtained 
a sufficiency of air through their gills, and were in conse- 
quence less readily converted. It appeared, further, that it 
is merely requisite to apply any external compulsion to- 
wards transformation up to a certain grade of development, 
and that when this has been reached the animals arrive at 
the higher form without any further interference. 
The point of time when the axolotl has arrived so far in 
its metamorphosis as to have totally lost the power of living 
in water does not coincide with the absorption of the gills. 
On the contrary, the most recent observations prove that 
the power of the axolotl to live in water may under certain 
circumstances be retained for a long time in individuals 
which have become completely adapted to a terrestrial life, 
and only disappears after the first moulting. Various expe- 
riments with axolotls which had passed through this stage 
proved indubitably that a return to their former life had 
become impossible ; they completed their metamorphosis 
even though all possible means were taken for its prevention. 
On the other hand, axolotls which had lived for months in 
