188 
Development of Hook-worms 
In this experiment the temperature was about 10° F. lower than in 
the preceding one. 
XV. The last experiment was intended to be a duplicate of the 
previous series. The faecal material was duly obtained in the early 
morning. The plates were prepared as before, but the sun remained 
overcast during the whole day. The plates were, therefore, covered 
and kept in the laboratory. Next day the sky was again heavily 
overcast and there was practically no bright sunshine all day. For 
that reason the experiment was again delayed. 
On the following day the clouds had somewhat dispersed and after 
midday the sun shone at fitful intervals. Two lots of material were 
exposed as before from 12.15 p.m. to 4.15 p.m. while a third lot was 
kept in the room. During this time the mean shade temperature was 
76-0° F. with a wet bulb of 67-6° F. The maximum solar radiation 
was 12T0° F. while the indoor temperature was 76-6° F. 
Cultures were made from all the plates at 4.15 p.m. and on each of 
the following four days. With few exceptions all the cultures produced 
numerous vigorous larvae. 
The results of this experiment do not appear to show any points of 
importance. It is evident that the interval of 48 hours at room 
temperature was sufficient to enable the eggs to hatch and the larvae 
to develop, and that the subsequent exposure to the open air for 4 hours 
was not sufficient to arrest the development. It may be noted, however, 
that a certain proportion of the larvae from the exposed dishes were 
inactive, though not dead. 
Summary and Conclusions. 
1. There can be no doubt that Ankylostomiasis has obtained a very 
firm hold in the coastal districts of North Queensland, and every effort 
should be made to arrest its spread, and if possible eradicate it. 
2. Experience in other parts of the world, notably the United States 
and Germany, has demonstrated the great difficulty of coping with the 
disease, even with the most energetic of preventive measures. 
3. The disease gives rise to much sickness and inefficiency especially 
amongst children, and although competent medical treatment is usually 
efficacious the most satisfactory and permanent results are to be 
expected in the direction of prevention. 
4. The chief preventive measures are individual cleanliness and 
thorough and rapid destruction of night soil and deposits of faecal 
material. 
