56 
L. Kaufman: 
cid appearance of the fin and of the gill-filaments. We therefore- 
must suppose that the first changes in the structure of the gills 
and fins of the specimens fed on thyroidine - tabloids proceed 
from loss of water. By weighing tadpoles undergoing meta¬ 
morphosis, Schaper ascertained considerable loss of water and 
from this he explains the diminution of turgescence in the 
body, especially observable in the tail; and, further on, the diminu¬ 
tion of capacity of blood-vessels of tadpoles during metamorphosis, 
which is characteristic of the gill-filaments of axolotls fed on 
thyroidine, Schaper also explains by changes in turgescence due 
to loss of water. 
Sexual glands. 
Axolotls fed on meat and thyroidine did not attain sexual matur¬ 
ity, when normally fed specimens of the same age had already laid 
eggs or spermatophores. Anatomical investigation has shown that 
the development of sexual glands was much retarded in the animal 
under consideration. This was especially observable in females- 
whose ovaries are small at a time when normally fed females lay 
eggs. I noticed only once large sexual glands and turgid oviducts 
in a female which had undergone metamorphosis after having 
received 1*25 gr. of thyroidine. 
My observations from which follows a retardation in the de¬ 
velopment of the sexual glands in specimens fed on thyroidine are 
not in agreement with the results obtained by authors working on 
the influence of the thyroid gland. Biedl gives a summary of 
these investigations; he concludes that the thyroid contains a hormon 
favourable to the development of the sexual glands. But if we take 
into consideration that the axolotls which have been induced to 
undergo transformation in 1879, by Chauvin, did not attain their 
sexual maturity and did not lay eggs until 1883, four years after 
metamorphosis, we see that changes occurring in the organism 
during metamorphosis hamper the sexual function. 
The thyroid gland. 
The behaviour of the thyreoidea in axolotls was particularly 
interesting. Assuming that metamorphosis depends on the function* 
of this gland, I hoped that the structure of the thyreoidea, its ab¬ 
sence or deficiency of development, would give us some guidance* 
