350 ON CHANGE OF MEXICAN AXOLOTL TO AN AMBLYSTOMA. 



few survivors did not make the change, but lived until the early part of 

 the next year, only to die one after another. 



Evidently I had given them too little care and attention, being pre- 

 vented by a somewhat lengthened absence from Freiburg, as well as by 

 other labors. 



I reached the conviction at that time that without the greatest care- 

 fulness and attention in the rearing no result can be obtained. This 

 conviction further experience only confirmed. One must just concen- 

 trate all his interest upon this one aim, and must not begrudge having 

 to devote considerable time every day for months to this work. That I 

 could not carry this on myself, without giving up other work for it, 

 seemed clear to me, and so I hailed it with joy when the opportunity 

 offered of seeing the experiments made by another person. 



Miss von Chauvin, a lady well known to several correspondents in 

 this department by her beautiful observations on the Phryganidae (alas, 

 not yet published), proposed the following year to take a number of the 

 larvae just out of the egg, rear them, and make the attempt to bring 

 them, in a certain measure, by force into the Amblystoma condition. It 

 will be perceived by the following records of the lady herself how com- 

 pletely this attempt succeeded, and no less will it be seen that this suc- 

 cess was possible only with such carefulness in the treatment and deli- 

 cacy in the observation as were here employed. 



EXPERIMENTS. 



"I began the experiments June 12, 1874, with five larvae about eight 

 days old, all that remained alive of the twelve delivered to me. On 

 account of the extraordinary tenderness of these larvse, the quality and 

 temperature of the water, the kind and quantity of the food supplied, 

 especially in the earliest period, exert a great influence upon them, so 

 that one can hardly be cautious enough in their management. 



"The little creatures were kept in a glass globe of about 30 centi- 

 metres in diameter ; the temperature of the water was regulated, and 

 as nourishment Daphnida were furnished at first, afterward larger 

 aquatic animals in greater quantity. In this way the five larvae throve 

 exceedingly well. By the end of June the strongest larvae showed the 

 beginning of the fore legs, and the 9th of July the hind legs made 

 their appearance. At the end of November I noticed that one Axolotl — 

 for brevity I distinguish it with I., and shall note the others with the 

 successive Eoman numerals — kept constantly on the surface of the water, 

 which brought mo to the supposition that the right time had come to 

 prepare for the change to a land salamander. 



" For this purpose, on December 1, 1874, 1, was put into a considerably 

 larger glass vessel with a flat bottom, which was so placed and filled with 

 water that only in one spot could he dive quite under water, while every- 

 where else in his repeated creepings about the bottom of the vessel he 

 came more or less in contact with the air. On the following days the 



