12 
NOTES OF OBSERVATIONS 
yards high. This return shows many important points ; we have the 
destruction of the crop on one acre where the Grub attack was not 
attended to ; also a trustworthy estimate of the amount of loss to be 
expected on shortness of crop following attack, and outlay thereon; and 
we have the thorough recovery based not on chemical or special applica¬ 
tions to destroy the Grub, but on the broad principle of supplying 
extra food to support the plant, and keep it up in heart, whilst 
suffering (i. e., starving) from more or less of its food supplies being 
cut off according to the greater or less amount of the stem gnawed by 
the Grubs. With regard to special experiments made at Mr. Fitton’s 
desire by Mr. A. Smetliam, of Liverpool, to ascertain the effect of 
various chemical applications on these Grubs, he mentions that it was 
found that a four per cent, solution of carbolic acid in water killed 
them in one to two minutes, and that in a solution of one part of 
carbolic acid to 250 of water they were killed in eight minutes. Blue 
vitriol killed them in about ten minutes ; green vitriol in less time; 
caustic potash and also lime did not seem to affect them much. The 
strong solution ot carbolic acid was experimented with in the field, 
but it proved useless practically, as on examination the Grubs were 
found within one inch of the surface of the ground watered with it. 
In cuy own experiments with regard to the effects of immersion in 
pure water, I found that although the Grubs appeared to be dead after 
remaining immersed for about fifty-eight hours, yet they recovered 
when they had been for about ten hours exposed to the air; the 
amount of further endurance of immersion was difficult to ascertain 
precisely, but the whole period did not exceed about five days and 
nights, as the Grubs then burst. Immersion in nitrate of soda caused 
an immediate and violent discharge from the intestines. With regard 
to the effect of cold, I was kindly permitted to have some specimens 
frozen at Kew Observatory by artificial means down to a temperature 
of -10°,—that is to 10° below zero, or 42° of frost, and though almost 
all the Grubs died under the experiment, yet it showed that excep¬ 
tionally the Grub could survive even this amount of cold, to all 
appearance uninjured, Mr. George Brown, jun., Caithness, also 
mentions instances being known of the “ Grub ” being frozen until 
quite brittle, and yet when thawed being as lively as ever. 
With regard to salt, Mr. George Brown mentions that he planted 
a number of Cabbages (all in a thriving state before the Grubs were 
introduced to them) in flower-pots. Salt was then applied upon three 
occasions, being increased in quantity until plant-life was destroyed, 
and on examination the Grub was found at increased depths in the 
soil, this depth below the surface seeming to be regulated by the 
amount of salt applied, but all the Grubs were found to be in no way 
the worse for the application. Mr. Bobert Service mentions that he 
