42 OTSTER-SHELL BARK-LOUSE. 



of applying it to the extreme branches. Mr. Walsh attempts to 

 explain why oily applications are more effectual than washes, by 

 saying that nature has made the scales of the Bark-louse water- 

 tight, but did not think it necessary to make them oil-tight. It is 

 a sufficient explanation, and I think a more probable one, that 

 greasy applications destroy all life beneath the scales, simply by 

 rendering them impervious to the air. 



There is one application from which I had been led to expect 

 the most satisfactory results from the strong testimony I had heard 

 in its favor, and this is fish brine — being the refuse liquid in 

 which mackerel and other fish have been pickeled. This possesses 

 two of the essentials of a universal remedy, namely cheapness 

 and a liquid consistency, so that it can be thrown with a syringe 

 over all parts of a tree. I visited the orchard of Mr. John Eobson 

 of Gralena, and saw the trees upon which the experiment with this 

 substance was, I believe, first made, some three or four years ago, 

 and about which a good deal was said at the time. It was asserted 

 that the scales peeled off from the branches to which it was ap- 

 plied, leaving the bark uninjured. I found the trees in a clean 

 and healthy condition, but some doubt was thrown over tiie special 

 efficacy of the application, by the fact that other trees standing 

 near them, and which had been treated with common alkaline 

 washes, were about equally clean. I made some experiments 

 with this remedy upon some infested trees in my garden, about 

 mid-summer, after the scales had become fully formed, but a little 

 before the time of depositing eggs, by dipping the ends of the 

 branches into a solution, such as Mr. Robson made use of, namely, 

 one pint of the brine to two gallons of water. If the application 

 were effectual it would of course arrest all future development of 

 the insects beneath the scales, and consequently no eggs would bo 

 found deposited. All such experiments have been rendered very 

 unsatisfactory the present season by the almost universal destruc- 

 tion of the bark lice and their eggs, as previously related, by para- 

 sites. But truth compels me to state that I certainly found scales 

 filled with sound eggs on the branches thus treated, very few, 

 indeed, but about as many as the Chalcides and other parasites 

 had left on the other branches. I suspect that whatever virtue 

 the fish brine may be found to possess, is due to the oil with which 

 it is largely impregnated. And even in this point of view it 

 may prove to be a valuable remedy by furnishing a cheap and 



