322 THE AMERICAN NATURALIST. [Vor. XXXIV. 
and advice in efforts to lessen the frightful destruction of wild life 
everywhere prevalent, the book will be an encouragement and an 
assistance. e e 
The Tree Frog. — A second interesting contribution to the natural 
history of European Amphibia by one who loves his subject is to be 
found in the Quarterly of the Natural History Society of Zurich, issued 
Feb. 15, 1899. H. Fischer-Sigwart, having previously described the 
life of Rana fusca,! now tells us of the habits of the tree frog, y/a 
arborea L. The spawning, larval life, feeding, hibernation, etċ., 
were studied both in the open and in his terrarium, where he kept 
many of these creatures (some for ten years), with greater satisfaction 
to himself than to his neighbors, who complained of the noise made 
by the ardent males. A tabulation of many observations upon the 
singing of these frogs and the state of the weather does not support 
the common belief in their powers as weather prophets, though show- 
ing that cold, stormy weather checks, as sr warm weather increases, 
their musical efforts. 
A long series of observations upon their color led to the result 
that they resembled the background in every case except one, slowly 
assuming various combinations of yellow, green, brown, gray, bronze, 
rust-red in harmony with the leaves, earth, cement, iron pipe, etc., 
they remained upon. 
For details we must refer to the —— pages of the origin 
A. A. 
The Protoplasm of the Salmon Egg.? — Professor His has added 
another study to his previous noteworthy work upon the egg of the 
salmon. As before, he emphasizes the study of live material, while 
the interesting photographs that accompany his paper show, as far 
as photographs can, the appearance of preserved and sectioned 
material. 
The ievtebite that collects in a heap (subsequently to divide 
into the cells of the blastoderm) acts, when removed from the egg, 
like a viscid liquid. It is made up of a clear * Hyaloplasma " and 
a turbid, granular * Morphoplasma." As development proceeds, 
these two parts undergo progressive changes in relative amount and 
arrangement. The changes in the distribution of these two parts 
1 See review in the American Naturalist, June, 18 
98. 
2 Protoplasmastudien am Salmodien Keim. 4/4. Konig. Sach. Gesell. Wiss. 
Bd. xxv, 1 
