THE PAN-AMERICAN EXPOSITION. 299 
fatal to the fungus and one which is harmless to the fish. The 
permanganate can not be applied as a radical cure. Its regular and 
constant use held the fungus attacks in check, but this is accomplished 
by salt, which also has certain advantages in application. 
Formalin was tried in weak solutions in much the same way as the 
permanganate and with substantially the same result, though it has 
advantages over the latter in greater safety for the fish. A chief 
objection to either of these substances, or any powerful agent requir- 
ing careful dilution and a short exposure to avoid killing the fish, is 
that more or less handling can not be avoided. On the other hand, 
the salt may be applied directly to the aquarium, where it passes slowly 
into solution and the fish can find different degrees of concentration. 
Though regular and constantly repeated applications are necessary, not 
much handling or transferring is required. On the whole, common 
salt is still the best remedy for the fungus trouble, which, under the 
conditions existing at Buffalo, can only be kept under control by 
constant attention. 
Filtration would be an efficient and radical means of removing the 
fungus, and would probably prevent the attacks, though the possibility 
would still remain of spores brought by the fishes themselves. The 
sand filter does not remove these, and the quantity of water used is too 
large for any form of earthenware filtration. There were some minor 
attacks of external animal parasites which did not give continuous or 
very great trouble. The salt treatment aided in checking these, and 
formalin dilutions are probably also valuable in such cases, but have 
not been well tried, as the attacks were only occasional. However, it 
may be said that when all the conditions which must be complied with 
are considered, none of the substances used can be said to possess 
decided advantages over salt, whether for fungus or for exterior ani- 
mal parasites. Other agents are more active and more fatal to the 
enemies of the fish, but none combines with parasiticidal powers 
the necessary qualities of cheapness, applicability, and safety to such a 
degree as common salt. 
METHODS AND STATISTICS. 
The fisheries of the United States represent an investment of about 
$60,000,000, giving employment to 200,000 persons, and are worth to 
the fishermen annually $50,000,000 in round numbers. While the 
bulk of the fisheries is carried on along the Atlantic and Pacific coasts, 
over $6,000,000 are invested in the fisheries of the Great Lakes, yield- 
ing to the fishermen $2,600,000 annually and employing 9,600 persons. 
Fish and other water animals form an important. factor in the food 
supply of the country when sold fresh, salted, or dried, and although 
modern methods have rendered it possible to preserve them fresh for 
considerable periods, it is not practicable to show them at expositions 
unless very extensive refrigerator systems are provided. Under fishery 
