1921.] 
New Zealand Institute Science Congress. 
33 
of two members whom all had looked forward to seeing at this Congress— 
Mr. K. Wilson and Sir David Hutchins. At his invitation the meeting 
stood in silence in their memory. After a philosophical discussion of 
research, and the reasons why man had, since the Palaeolithic age, indulged 
in it, and insistence on the close, inseparable relations between pure and 
applied science, he went on to emphasize its national importance, com¬ 
paring the expenditure on it to that for fire insurance. He trusted that 
when any scheme for its encouragement was formulated by the Govern¬ 
ment it would include four provisions. The first was that the Government 
Departments shall be strengthened by the appointment of men who would 
devote all their time to research, and not be called off from time to time 
for routine work until their enthusiasm had had time to evaporate. The 
second was that the University professors of science in all the colleges should 
be given such assistance as would enable them to devote, not their leisure 
or their vacations, but the major part of their time to research and super¬ 
vising the research of their students. The third was that the fullest use of 
existing institutions, such as the Cawthron Institute, should be made, and 
that freest co-operation should exist between them all. The fourth was that 
what might be called amateur research—the sort encouraged by the present 
series of grants given out under the recommendation of the New Zealand 
Institute—should be retained. 
Public Lectures. 
Public lectures were given on Wednesday and Thursday evenings in the 
Town Hall, and were well attended by the citizens and visitors. On 
Wednesday Dr. Tillyard gave an illustrated address on 44 Modern Methods 
of Scientific Control of Insect Pests.” American practice, he said, was 
far above British in these matters, and he must “take off his hat” to the 
Americans. Time permitted of a selection only of cases illustrating the 
general principles involved. The first was quarantine and fumigation at the 
ports of entry. In Honolulu the sugar-planters had thought it worth while 
to supplement the salary of the Government officers in order to secure 
fully qualified men, and the museum of the pests that had been detected 
and kept out was a most educative one. Various mechanical devices for 
catching or trapping insects were described, and spraying was also illus¬ 
trated by a picture which looked like a fire brigade at work, throwing 
spray over a high forest-tree. It was found that the important thing in 
spraying was the pressure, and large quantities of weak solutions of the 
sprays were used. Injections of chemicals into the sap of trees was at 
one time believed to be of little use, but recently the Italian Government 
had had great success by this method, though it was being kept a close 
secret at present. The most successful methods of control were biological. 
These were of two kinds—the selection of strains immune from disease, 
often the only possible and sometimes a very successful method of meeting 
the ravages, and control of insects by their own insect enemies. Predatory 
insects often served to keep pests under control, and many such could 
be advantageously introduced into New Zealand. 44 Big fleas have little 
fleas upon their backs,” and very many insects could be controlled by their 
own parasites. In introducing useful insects to a country it was all- 
important to see that their own parasites were not introduced at the same 
time. The lecturer concluded with an account of his own work in bringing 
to New Zealand an enemy of the woolly aphis. 
On Thursday Mr. J. H. Edmundson, of Napier, gave a lecture on 
44 Liquid Air ” It was illustrated by lantern-slides of famous investigators 
8—Science. 
