ELM-BARK BEETLE. 47 
cation, which would be repulsive to the operators, even if not prejudicial 
to health, there would be difficulty without the use of long ladders in 
managing to coat the trees with the mixture as high up as is needed. 
A less objectionable mixture, known in Canada as the “ Saunders’ 
Wash,” forms a tenacious coating on the bark, and is found service- 
able there as a preventive of ‘‘shot-borer’’ beetle, serving equally to 
keep the beetles from getting in, or getting out. This is composed of 
soft-soap reduced to the consistence of a thick paint by the addition of 
a strong solution of washing-soda in water; and if applied to the bark 
of the tree during the morning of a warm day, will dry in a few hours, 
and form a tenacious coating not easily dissolved by rain. Ina further 
communication, which Dr. Fletcher (Entomologist of the Experimental 
Farms, Department of Agriculture, Ontario, Canada) was good enough 
to send me on the subject, he mentioned :—‘‘ With regard to the soap- 
wash suggested for Xyleborus dispar, I have this year suggested the 
addition of carbolic acid, which I feel sure will have a good effect.” 
A process was tried with success by our Botanic Society, so far back 
as the year 1842, which might be serviceable for saving special trees, 
but would hardly be applicable for work on a large scale. The plan 
consisted ‘in divesting the tree of its rough outer bark, being careful 
at the infested parts to go deep enough to destroy the young larve, 
and dressing with the usual mixture of lime and cow-dung.” * 
A series of French experiments based on the plan sometimes used 
of paring off the outer bark to restore vigour to bark-bound apple 
trees, and also on observations that where a vigorous flow of sap was 
brought about under Elm bark that many of the bark maggots were 
killed, were instituted as to the effect of having the whole of the rough 
outer bark of the Elm cut or shaved away. This operation caused a 
sreat flow of sap in the inner lining of the bark, and the grubs of the 
Scolytus beetle were found in all cases to perish shortly afterwards. 
Whether this occurred from the altered sap disagreeing with them, or 
from the greater amount of moisture round them, or from the maggots 
being more exposed to atmospheric changes, or any other cause, was 
not ascertained; but the trees that were experimented on were cleared 
of the maggots. The treatment was applied on a large scale, especially 
on Elms infested by Scolyti along the Avenue of Neuilly, the Boulevards, 
the Quai d’Orsay, &c., Paris, and the barked trees were found, after exa- 
mination by the Commissioners of the Institute at two different periods, 
to be in more vigorous health than the neighbouring ones of which the 
bark was untouched. More than two thousand Elms were thus treated.{ 
* Details, with illustrations, were given in a paper read in 1848 before the 
Botanic Society. 
+ The above account is abridged from the leading article in the ‘ Gardeners’ 
Chronicle and Agricultural Gazette’ for April 29th, 1848, 
