ZOOLOGICAL GARDENS—LOISEL. 445 
Before returning there, however, this water undergoes a series of 
successive filtrations; it first falls into a linen cloth suspended at the 
end of the conduit, then it passes through a wooden grating that sup- 
ports the cloth and afterwards traverses a bed of sand and gravel. 
All the tanks have sandy bottoms, and one may see how the natural 
colors of the soles, flounders, etc., harmonize with them. They are 
also provided with artificial rocks covered with aquatic plants that 
form a dark background and enable one to see the animals perfectly 
and observe their behavior. No description indeed can do justice 
to the effect produced by these great fishes swimming gracefully in 
the transparent water of an enormous tank 5 or 6 meters long lighted 
by a diffused light in which their pearly colors sparkle. 
In the little room at the back are found on separate tables a cer- 
tain number of small glass aquariums, some cubical, others cup- 
shaped, for small marine animals and others, the temperature of 
which is kept constant by means of a thermo-regulator constructed 
according to the system of Prof. Max Weber. These aquariums 
contain exotic fishes from the Dutch Indies, from South America, 
China, ete. 
The Amsterdam garden has also a special installation which I 
previously saw attempted only at one other place, the Zoological 
Garden at London; that is an insectarium, which, commenced in 
1898 and enlarged in 1899, is now confided to the care of Mr. Polak, 
a teacher at Amsterdam. 
This insectarium is not at all like the farms for raising butter- 
flies which I visited in England, but it resembled them in paying 
especial attention to the rearing of nocturnal moths which in Hol- 
land constitute 95 per cent of the Lepidoptera. It is composed of 
a certain number of small cages or glass cases resting upon boxes 
and arranged entirely around one of the rooms of the reptile house, 
decorated with palm trees and green plants, which give it the ap- 
pearance of a little conservatory. 
Each insect cage is formed of a glass case without cover, placed 
with its opening downward on a zinc box, the upper surface of which, 
pierced with holes and covered with sand or moss, supports wide- 
mouthed vessels containing fresh plants on which the caterpillars 
feed. The glass of the top of the system is often replaced by a 
grillage and supports little insect boxes containing dried specimens 
of the same species that are seen alive below. 
RESUME. 
Since my journey was limited to the United Kingdom, Belgium, 
and the Netherlands, it is not possible to draw from it any conclu- 
sions regarding zoological gardens in general, yet it may be well to 
give here a sort of synthetic résumé of the principal facts observed, 
