REPORT OF COMMISSIONER OF FISH AND FISHERIES. 53 



out the entire period of incul)ation, thus eausiuo- the Cj^^s to deveh)p 

 very .slowl}. Hatching- bejj;an May 8 and closed on May 12. 



The superintendent was criven authority to make some experiments 

 with the view to making improvements in the form of hatching jar, 

 having in mind convenience in manipuhition and general results. 

 Accordingly, a jar was designed somewhat after the pattern of the 

 Chase jar, except that it has a glass instead of a metal spout and is 

 made smaller at the top than at the bilge, thus concentrating the cur- 

 rent of water and giving a good motion to the eggs at the top as well 

 as at the bottom. The new jar was received January 18 and a poor 

 lot of eggs placed in it. It was found that these eggs cleaned up 

 faster in the new jar than in any of the older forms, that about a quart 

 more eggs could be worked in it than in either of the other jars, and 

 that it required but two-thirds the volume of water required in the 

 older forms. From an economic standpoint and for convenience in 

 handling it is claimed by the superintendent to be far the best jar used 

 at the station. 



NORTHVILLE STATION AND SUBSTATIONS IN MICHIGAN (FrANK N. ClAEK, SuPT. ). 



In the output of eggs and fry the past year's operations at the sta- 

 tions in Michigan have been'the most successful of any since the com- 

 mencement of the work. There are two regular stations in the State, 

 one at Northville and the other at Alpena, and in addition to these the 

 hatcheries at Detroit and Sault Ste. Marie, belonging to the Michigan 

 Fish Commission, have been operated the greater part of the year, 

 Northville Station being the headquarters. 



At the beginning of the 3^ear there were no fish or eggs in the 

 Northville hatchery, and the number of fish in the ponds was very 

 small. For the first two or three months, therefore, the force were 

 engaged in preparing for the reception of eggs, maintaining the build- 

 ings, ponds, and grounds, and in construction work. 



Three old wooden ponds were torn out, and in their place two cement 

 ponds 50 feet long, 8 feet wide at the surface, and 6i feet wide at bot- 

 tom were constructed, the cement being 5 inches thick on the sides and 

 4 inches on the bottom. These ponds are supplied with water from a 

 spring under the hatchery, which flows about 135 gallons per minute, 

 the temperature being 48° F. They were constructed for experimental 

 work in connection with the bacterial disease that has caused great 

 mortality amongst the brook trout in past years. Fish not affected 

 by the disease were brought from the Au Sable River and introduced 

 into the ponds. 



The experimental work is being conducted under the direction of 

 Mr. M. C. Marsh, and further mention of it is contained in the report 

 of the Division of Scientific Inquiry. 



