TRANSACTIONS OF SECTION I. 547 
Amblyomma hebreum. This tick leaves its host between each moulting, and a 
larva which sucks the blood of an infected animal is capable of giving rise to the 
disease in a susceptible animal either as a nympha or imago. The distribution of 
this tick corresponds to the distribution of the disease. If this tick could be 
killed off, the disease would disappear from the country. This could doubtless be 
done on individual farms by long-continued dipping; but in the meantime some 
method of immunisation might be devised. 
CAPE TOWN. 
WEDNESDAY, AUGUST 16. 
Discussion on the Effect of Climate upon Health. 
Sir Lavpur Brunron said the effect of climate upon health was very ill- 
understood. It was in the same crude condition as the effect of drugs had been 
forty years ago. Any particular climate was the resultant of many factors, and 
was, as a rule, very incompletely analysed into its components. 
Three primary points had to be considered with regard to any climate, namely, 
its action (1) on the human body ; (2) on the organisms which give rise to disease ; 
(3) on the carriers of disease. 
The most general way of commencing an investigation of the subject would be 
a consideration of the effect of various climatic conditions upon protoplasm, For 
every cell there was an optimum temperature correlated with an optimum humidity ; 
there was also an optimum degree of salinity for cells in a fluid medium. A series 
of determinations was necessary in order to obtain a definite guide as to the 
needs of the cells in the human body for water, ‘The optimum of temperature for 
the body was 98°-4 F, When the temperature fell below that the force and rapidity 
of muscular contraction altered. The same diminution in vitality was to be seen 
in the metabolism generally. The amount of heat produced in the tissues was a 
very important factor in the temperature regulation of the body ; this in its turn 
depended upon the degree of activity of the various organs. This point would be 
dealt with in greater detail by Mr. Barcroft at a later stage in the discussion. 
Over-exertion, however, predisposed to heat apoplexy, and complete inaction led 
to similar result. Climate, both in the matter of temperature and of moisture, 
was much affected by the nature of the soil. The soil also affected health by 
imparting its saline ingredients to the water, and the effects so produced on the 
patient were often mistaken for climatic effects. High winds intensified the 
general thermal conditions. Of the effect of electrical changes little was known. 
It was a matter of common knowledge that thunder was accompanied by head- 
ache, depression, and dulness in the case of many people. Weir-Mitchell had 
gone rather more definitely into the matter, and had found by a comparison of 
the reports from his patients with those of the meteorological authorities that 
a wave of pain passed over the American continent synchronously with a wave of 
elactrical disturbance, as evidenced by rainstorms, traversing the United States, 
The rain areas were concentric with, but smaller than, the pain areas, Changes 
in barometric pressure had been studied by Dexter, who correlated a low pressure 
with crime, insanity, bad conduct, sickness, and suicide; with a high glass 
drunkenness was reduced and clerical errors were fewer. 
Dr. Grueory dwelt on the lack of meteorological statistics which South Africa 
could provide in years past. In South Africa there were only two winds, easterly 
and westerly, each of which blew for half the year. It was noticeable that 
infectious diseases, as small-pox, typhoid, scarlatina, and influenza, occurred in a 
very mild form. Tuberculosis, however, was becoming a great scourge, causing 
a death-rate of 17 per 1,000 among the natives and 7 per 1,000 amongst the 
white population. It did not seem clear whether or not these facts were due to 
the climate. 
Professor Bour spoke specially of the effect of high altitude. He said that 
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