256 
The N.Z. Journal of Science and Technology. 
[-July 
them. All bacterial diseases conferred a certain degree of immunity on the individual 
attacked—with some their immunity seemed to be lifelong—but with fevers such as 
influenza the immunity was not absolute and it was not of long duration. Probably 
six to ten weeks would cover the period of effective resistance against reinfection, and 
the same would apply to artificial immunity conferred by vaccination. 
He thought that the people who were afflicted with the mild influenza of Sep¬ 
tember and October enjoyed a fair degree of immunity against the more serious illness 
of November. That immunity was not present in all cases, for he had known of cases 
where people who suffered in the early epidemic were again attacked in November. 
The period of infectivity was probably greatest during the early stages of the disease, 
but must persist to a certain extent right through the illness.. The infection was con¬ 
veyed by contact and inhalation of the secretions from the air-passages of an infected 
person, and the period of incubation appeared to be about forty-eight hours or less. 
It was not likely that infection could be conveyed very readily by air or water. 
Drying under ordinary atmospheric conditions was rapidly fatal, and even in large 
masses of expectoration the bacteria did not Jive longer than two days, and that 
period covered the extent of their existence when kept in water. Tn the artificial 
media used for their cultivation he had kept them alive for ten days, but the usual 
term was about five days. The presence of blood in the artificial medium was 
essential for primary culture of the true bacillus, but some of the variant obtained in 
cases of meningitis would grow moderately well without blood. 
The lecturer proceeded to outline the measures to be adopted to guard against 
infection, laying especial emphasis on the importance of fresh air. 
A vote of thanks was passed to the lecturer, on the motion of the Hon. G. M. 
Thomson, M.L.C. 
PAPERS, ABSTRACTS, AND TITLES. 
Section i.—Biology and Agriculture. 
Yellow Flax Disease of Phormium tenax , by L. Cockayne, and 
A. H. Cockayne. 
Press Notice (Lyttelton Times). 
Dr. L. Cockayne said that the disease was rapidly affecting areas of flax, especially 
in the North Island. He described the botanical character of primitive flax swamps, 
and showed how they could be turned into commercial flax areas. New Zealand 
swamps, he continued, usually were raupo swamps, and if they were drained there 
were growths of magnificent flax. The yellow flax disease appeared suddenly about 
three years ago and now had caused considerable damage. The symptoms were that 
the leaf of the flax became bright-yellow, and then the plant died. 
Mr. A. H. Cockayne supplied figures to show the value of the flax industry to the 
Dominion. In these days the flax-miller really was a flax-farmer, as the industry 
would have disappeared if the miller had not learned to farm the plant. Stubborn 
lands could be best dealt with by turning them first into flax areas for a few years 
until the flax had made the ground suitable for grassland. He viewed the presence 
of the leaf-disease with great alarm. It could be combated by discovering if any types 
of flax had powers of resistance to the disease, and those special varieties could be 
cultivated. The di.sease was due to a fungus in the tissue, which attacked the rootlets 
or the main roots. Work was being done at the State farm at Weraroa in the culture 
of fungi on diseased flax, and, experiments were being made to discover what would 
act against the disease. It was believed that the destructive fungus was similar to a 
fungus that attacked the cotton-plant in the United States. 
Professor I 1 . H. Easterfield described some of his investigations into, the character 
of the flax-plant. 
The lectures were illustrated by lantern-slides. 
Seed-testing, by E. B. Levy. 
(This paper has appeared in the N.Z. Journal of Agriculture, vol. 18, No. 3, 
pp. 130-39, 1919, under the title “ Seed-testing : The New Zealand Official System. ’) 
