63 



seemed to agree that stronger solutions were injurious to vegetable 

 life. But from the following statement, made by Wm. Mead, Jun., 

 of Taunton^ Massachusetts, it appears that even the very strongest 

 alkaline solutions have no effect upon Bark-lice. "To kill the scale- 

 insect," he says, "upon my pear trees, I have tried potash — one pound 

 to a gallon of water — which has no effect upon the insect, except to 

 make it brighter." {New YorJc Sent. Tribune, March 16, 1866.) 

 Judging from the date of publication, Mr. Mead must have operated 

 in the dead of the year, and therefore upon the perfected scale. Dr. 

 Houghton, of Philadelphia, used in the summer time a wash of the 

 same unusual strength, as he has informed me — one pound of "con- 

 centrated lye" to one gallon of water — upon the other species (Har- 

 ris's Bark-louse) that were infesting his pear trees in prodigious 

 numbers, without its producing the least perceptible effect in dimin- 

 ishing their ravages, though he was of opinion that it injured the trees 

 to a considerable extent. 



Statement 3d. — On June 12th, 1867, I prepared a solution of 

 good, home-made soft soap, manufactured from soap-grease and what 

 is sold under the name of "concentrated lye," and is probably nothing 

 but impure soda. I took one part, by measurement, of soap to six 

 parts of water, and stirred the mixture over a fire till it got warm 

 and had about the consistence of thin paint. This I applied, in the 

 same way as the tobacco-water in the first experiment, to a branch 

 prepared and labeled in the same manner, except that I had unfortu- 

 nately omitted to trim off a few of the small, terminal twigs, and 

 neglected to apply the soapy solution to those twigs. On examining 

 this branch, from time to time through the months of June and Jul}^, 

 it was quite plain that the great bulk of the young Bark-lice on it had 

 ceased growing and were dead, though they still adhered firmly in 

 their original form to the bark. On October 27th, I cut off a portion 

 of this branch, of the same size and length as in the other two experi- 

 ments, and carefully lifted and examined, under the lens, all the 

 matured scales upon it, whether of this year's or last year's growth. 

 I found but seven scales containing plump, healthy eggs ; the number 

 of last year's scales, and of those that had been operated on by Mites, 

 I did not count, nor did I estimate them separately from each other; 

 for, up to this day, I had not become aware of the nice distinction 

 between last year's scales, containing wliite egg-shells, and scales re- 

 cently gutted by Mites, which contain yellowish egg-shells. But I 

 estimated the whole number of matured scales, containing no living 

 and plump eggs, at several hundreds. x\fter the above process had 

 been gone through with, which necessarily obliterated or removed 



