■64 
L. Kaufman: 
of the respiratory apparatus is so strictly parallel with loss of weight 
that they must obviously be connected together. In experiment 19 
in which the weight curve (Nr 3) descends more slowly than the 
curves Nr 1 and 2, which belong to experiment 15 and 16. the 
reduction of the gills and of the fin took place more slowly. If we 
drew curves representing the length of the gills during the period 
of decreasing weight, these would run parallel to the weight-curves. 
For a more thorough examination of whether the rise of dis¬ 
assimilatory processes may cause resorption of gills and fin and 
lead to metamorphosis, I have endeavoured to accelerate metabol¬ 
ism in axolotls by means of other factors. 
In specimens subjected to starvation, I never remarked dimin¬ 
ution of giils or fin. For the acceleration of metabolism, I there¬ 
fore gave castor oil and phenolphthaleine for nearly two months 
to one axolotl subjected to starvation. The larva became thinner 
but neither its gills nor its fin underwent diminution. The loss of 
weight of this specimen attained 19% of the initial weight 1 ). The 
axolotl Nr 8 which had been fed on small quantities of thyroidine 
(about 05 gr.) lost only about 20% of its initial weight and un¬ 
derwent nevertheless transformation. This would appear to disagree 
with the view that rise of disassimilatory processes causes the di¬ 
minution of gills, and to prove that thyroidine has some formative 
power, the acceleration of metabolism being no more than a side- 
issue. But if we take into consideration that the axolotl which had 
consumed nothing but castor oil and phenolphthaleine lost 19% 
in two months, and that, on the other hand, a specimen abund¬ 
antly fed on meat with small doses of thyroidine lost the 
same percentage in 3 weeks, we perceive that thyroidine causes 
disassimilatory processes more intense than starvation and purga¬ 
tives. The resorption of the animal’s own tissues which (as it pro¬ 
ceeded slowly), in the first case, might have been distributed among 
all organs, took place rapidly in the second, and affected first less 
resistant organs, which the gills and fin certainly are. The ema¬ 
ciation at any rate does not always affect the same tissues; it de¬ 
pends on the course of that process and on the state of the spe- 
*) ln Morgulis’ investigations, the amphibians deprived of food lost 20 , 8 0 / o 
weight in 58 days, a proportion which almost exactly agrees with the loss of my 
axolotls subjected to starvation and fed on purgatives. 
