15 
experts in this country, could discover all possible sources of conta- 
gion. Nor is there any method of fumigation or disinfection that is 
absolutely effective. We have, therefore, no means of assuring the pre- 
vention of the introduction of noxious insects or fungous diseases by 
inspection or treatment. 
If the principle of protection from foreign pests were followed out 
legitimately by all countries, it would practically stop the commerce of 
the world, except in mineral substances, and even then the chance of 
stowaways would not be avoided. Hither we must build a Chinese 
wall and live entirely apart from the rest of mankind, or make up our 
minds ultimately to be the common possessors of the evils as well as 
the benefits of all the world. 
There is another view of this phase of the problem of insect control 
which has latterly impressed itself upon us much more than formerly, 
namely, the undesirability of exciting alarm on the appearance of a new 
pest. A subject taken up as was the San Jose scale grows in impor- 
tance from week to week and as it spreads from country to country, 
while as a matter of fact the insect itself and the likelihood of damage 
may not be essentially different in kind from that to which we are sub- 
ject from a hundred other insects, and which attends every shipment 
of plants or fruit from any quarter of the world; but suspicion aroused, 
- restrictions on commerce and exchange follow. 
It seems to me, referring again to the San Jose scale, that the chief 
distinction between this insect and many other imported species is not 
that it is so much more destructive and dangerous, but that it had the 
bad fortune (for us) to get thoroughly established in two of the leading 
Eastern nurseries and to be thence distributed over a very large extent 
of territory in a very short space of time, so that during its first and 
most destructive period in the East it was brought into very general 
notice. It is not especially feared to-day in California, and, in fact, it 
is looked upon by some of the largest fruit growers—as I am informed 
by Professor Washburn—as having been of positive advantage, the 
yearly treatment of trees having necessitated a system of regular short 
pruning, which has greatly improved the quality of the fruit and much 
lessened the expense of gathering. The experience on Catawba Island, 
which is familiar to all of us, is another case in point, and I venture to 
predict that this insect will not be especially feared in the near future 
by our Eastern fruit growers. 
Aspidiotus ostreeformis, recently introduced from Europe, is liable to 
be just as dangerous an insect as perniciosus, and if it should be simi- 
larly widely distributed and equally actively exploited would doubtless 
assume a similar importance, but with this advantage, that coming 
from Europe to us there could be legitimately no restrictions on our 
commerce by European powers in consequence. 
Recently the Department was urged by an enthusiast on the subject 
to prepare and distribute an alarm circular or bulletin on Aspidiotus 
