SCIENCE. AND INDUSTRY. 
and active in distributing spores. The presence of rust spores between 
the glumes of wheat florets could thus be accounted for. Ludwig called 
attention to the interesting fact that smut spores, which have a rough- 
ened cell wall, are found in those parts of their host which are regularly 
visited by insects, while the smooth-spored species occur on wind-polli- 
uated plants, or on parts that are not regularly visited by insects. 
Species of fruit flies distribute the spores of the Bitter Rot of pome 
fruits caused by Glomerella cingulata. Although the washing and dash-- 
ing about of the potato plant by rain and wind are the most active means 
of spreading Late Blight (Phytophthora infestans), insects, especially 
beetles, carry the spores greater distances, 
IL. Iyrernat TRANSMISSION. 
(c) Mechanical. (d) Biological. 
The parasitic organism (c) may pass passively through the insect, 
or (d) may remain and multiply within the body. In the first case, 
there may be overlapping with the mechanically carried condition, as 
many organisms may be both externally carried and internally 
mechanically transmitted, passing into the digestive system with the 
food of the insect. The organism may leave the body by two ways. 
Very many insects are provided with a storage sac or crop, and such 
insects commonly regurgitate some of its contents, either as a result of 
overfeeding, or to moisten the food they are about to ingest. , Ants 
regurgitate their food to feed their young. It is a well known dirty 
habit of the house fly that it vomits on its food before feeding, and 
these vomit spots invariably contain infective germs. Graham Smith 
found that house flies (Musca domestica) defecated from three to eleven 
times per hour, atid vomited from six to fifteen times an hour, 
the rate depending on the temperature and food. They are 
attracted equally by food and by filth, and this commingling of 
_ tastes leads to the spread by flies of such diseases as typhoid, dysentery, 
infantile and summer diarrheas, tuberculosis, ophthalmia, cholera, &c. 
People in Australia are far too indifferent to the dangers from house 
flies, and too little care is taken to prevent their access to latrines, feces, 
garbage, and other sources of infection. Very seldom do we find suffi- 
cient protection for all food in the house, especially milk (and cups) 
used for feeding children. Flies have been well named by Hewitt “The 
sanitarian’s red lamps,” indicating danger from the presence of filth, 
and also the “ Potential destroyers of human life.” 
The transmission of the bubonic plague organism (Bacillus 
pestis) by fleas is probably well known to most people, al- 
though there has not been an outbreak in Australia for many years 
past. Plague bacilli have been found in the intestines of fleas, 
in some cases three weeks after ingestion, but it has not been shown that 
any multiplication takes place. They are inoculated by the flea-bite, or 
by scratching parts of the bodies. or feces of infected fleas into the 
skin. 
Among Fungi the well-known “Stink Horns” (Jthyphallus spp.) 
attract insects, especially flies. ‘So powerful is the attraction that it is 
sometimes almost impossible to hunt the flies away. Ants also carry 
the spores under ground to their nests, and, no doubt, the fungi find 
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