78 Thirtieth Annual Meeting 



are all natural earth banks or they arc wood, and yet they never 

 have the disease. 



Prof. Marsh : Of course that seems strange, but there was a 

 time when the disease did not occur in these wooden ponds. The 

 infection has got to occur there after a certain length of time — 

 it will come. 



Mr. Brown : I would ask, where they have the wood pond, if 

 tlie wood was not treated with some kind of paint that made it 

 impervious to germs — creosote or coal tar? 



Prof. Marsh: That is practically proposing to make the 

 equivalent of cement. If you can put wood in the ground and 

 make it impervious, well and good, but I do not l)elieve that you 

 can do it. You can make an impervious box or bank above the 

 ground, Imt if it is in the ground how can you protect it from 

 being heaved by the frost? It would be very difficult, you see, 

 and rather difficult to make it tight. In this climate I suppose 

 it would be upheaved the tirst winter by the frost, and that is 

 possibly an im])ortaut objection to the cement or stone ponds; I 

 cannot find where they have been experimented with during liard 

 winters. 



Mr. Clark : Was this question lu'ought \ip by Mr. Brown in 

 regard to the wood ponds, that if they were properly coated with 

 something that that might be a preventive of germs ? 



The President : Yes. 



Mr. CUark : Prof. Marsh has not touched upon that. But 

 the disease now, as he says, has developed in ponds having 

 cement sides and no wood. That helps to carry out the theory 

 that this disease worlds in. I now have orders from the commis- 

 sioner to build two i)onds in accordance with Prof. Marsh's sug- 

 gestions, that is, entirely of cement, l)ottom, sides and ends. 

 The water goes through nothing Init ciMuent tile. We thus hope 

 to avoid the ])ossibility of the introduction of germs. Four of our 

 pi-esent ponds have cement sides but not cement l)ottoms, so the 

 ilieory of the painted wood sides cannot figure in this nuitter. as 

 cement sides are certainly as effective as ])aiuted wood iu kee])ing 

 out disease. 



Mr. Ne\iii: W'c have never luul any loss anu)ng the small 

 fry or yearlings, but our loss has been among tlie largest trout. 



The President: Those that have been in the pond longest. 



