APPENDIX IV. 



gus. It is also one of the most durable and easily handled 

 things in the world. And this is not all. It has invari- 

 ably been my experience that in any instance where the 

 carbonized hatching troughs have been used, not only have 

 the eggs been free from fungus, and have therefore hatched 

 better, but the young fry have lived better; and the con- 

 trast between the effect of the charred wood and the raw 

 material in this respect has been very marked indeed. 

 While the young fish, hatched in the old wooden troughs, 

 seemed to drop down dead from no assignable cause, the 

 fry hatched in the charred troughs showed a wonderful 

 tenacity of life, that became more and more surprising 

 every day. I have hatched over a million eggs in these 

 troughs, and speak from experience, and my experience 

 has been, without an exception, to confirm the belief that 

 the fry hatched in this material do not die as they did 

 under the old method. It is a fact that can be confirmed 

 by my assistants, that in some of the charcoal troughs last 

 year less than one-tenth per cent were lost by death in the 

 first three months, with the exception of deformed ones. 

 This year it has been the same ; and if any one will take 

 the pains to visit my hatching house, I will show him 

 charred troughs, which the water has run through for six 

 months or more, that are as clean from fungus as when 

 the water was turned on in the fall, and also troughs of 

 young fry, where death is a rare occurrence. 



The exclusive right to use charcoal and charred wood 

 for hatching fish eggs has been secured to the writer in 

 the United States by letters patent ; but even with the 

 royalty paid for the right to use charred wood it is still 

 the cheapest thing that can be found, as well as the best. 

 The reader can see the saving in expense in the use of 

 charcoal troughs over glass grilles by looking at the fol- 

 lowing figures: 



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