107 
nnon being the cessation of the heart’s action. As the young were 
transparent when viewed by transmitted light, the motion oi the 
heart of living specimens was easily detected. 
Whale Oil Soap. 
From the 19th to the 22d several experiments were tried by dip- 
nine the leaves in a solution of whale oil soap, or brushing then 
surfaces with it, but as the strength of the solution was not noted 
in these preliminary trials, I need only say that they were m a 
cases effectual. 
Experiment 10.—On the 23d a branch of a tree infested with 
bark lice was dipped in a suds of whale oil soap containing a pound 
to a gallon of water, and on the morning of the following day the 
lice were all dead. Two days later, however, the leaves dipped in 
this solution showed signs of injury, the margins of most of them hav¬ 
ing blackened and dried up. Naturally the younger leaves at the 
tin of the branch were most severely injured, some having been 
almost wholly destroyed. On the 29th, nearly all the leaies iai 
fallen off this branch. 
Experiment 11.—On the 25tli July, leaves were dipped in a solu¬ 
tion containing a quarter of a pound of whale oil soap to the gal¬ 
lon. and on the 26th the bark lice were mostly dead, only a small 
percentage showing a feeble movement of the heart. 
Experiment 12.—The above experiment was varied by using a so¬ 
lution double the strength just mentioned. On the following day 
all the specimens examined were dead. 
Experiment lS.-On the 28th, experiment 12 was repeated with 
identical results, all the bark lice being dead two days later. 
Experiment 14.—This was a repetition of experiment 11. The 
twins were not examined, however, until five days atterwards. 
S time, at least seventy-five per cent, ot bee npon the 
lpavpq were dead and many which were not killed seemed to nave 
been driven from the leaves as if the soap suds were obnoxious to 
ttm TMs was shown by their having fixed themselves upon 
petioles and twigs, a fact not elsewhere observed so early m t 
season. The leaves were again very slightly injured at then 
gins, and a few, perhaps, eventually fell before then time. 
Experiment 15,-A repetition of experiment 
treatment not a single living baik louse cou c , i 0 ^at 
containing a hundred or so, all being brown and loosened, so tnat 
a touch dislodged them. The leaves, howevOT, were slightly bkaek- 
ened at the . margins, and some were doubtless mjuied enoug 
cause them to fall. . 
satisfactoiy^thaii th§se with the kerosene emulsion an appheation 
of the suds, strong enough to effect the P^°*f; b «f ^ 
to injure the leaves at least as much as t ie 
done. 
