230 QUEENSLAND AGRICULTURAL JOURNAL. [1 Serr., 1898. 
which does not answer quite as well) for twenty-four hours or so. By this 
means all the fatty matter, epithelial cells, and granular débris, which make up 
the bulk of the scale, are, as it were, dissolved away, and only the fungus itself 
is left—much in the same way that the framework of a leaf may be obtained by 
dissolving away its softer parts, by prolonged maceration in water. The fungus, 
when thus obtained from a scale, appears as a fine net or morsel of tangled sea- 
weed, which can be picked up on the point of a needle, and further cleansed by 
rinsing in clean water. Under a low power of the microscope it will be seen to 
be made up of innumerable interlacing fibres, technically known as a 
mycelium (see Fig. 1, Plate XLIX.) 
If an attempt be made to tease out this network with a couple of needles, 
it will be found that the fibres of which it is composed are quite tough and 
resistant. 
Another way to study the fungus is to grow it artificially ; all that is 
necessary to do this is to plant one of the scales or scabs on some substance 
which will afford it moisture and nourishment. The sloping surface of a test 
tube of nutrient Agar-Agar* mixture, such as is employed by bacteriologists 
for the cultivation of microbes, answers splendidly. It has also the advantage 
that, being transparent, it permits of the growth of the fungus being easily seen, 
and even watched from day to day. If a mange scale, so planted, be examined 
at the end of twenty-four hours, a zone of common microbes, all manner of 
which are of course abundant in the scale, will be seen to have grown around it, 
and these organisms will continue to gradually spread from itsedge. Aboutthe 
fourth or fifth day, however, if the tube be held between the eye and the light, 
very fine, transparent, hair-like processes may be detected shooting out from 
beneath the zone of common microbes that surrounds the scale; these are the 
mycelial hyphe of the mange fungus. Once they emerge from beneath the 
growth of adventitious microbes, they quickly extend till they come in contact 
with the sides of the tube, and then turn upwards into the air. Soon the 
surface of the jelly becomes covered with the growth, and the hyphw, shooting 
upwards, give it a soft, pure-white, blankety appearance. In a tew days this 
blanket will have grown to the thickness of a quarter of an inch, looking for 
all the world like a layer of snow-white cotton-wool. A morsel of this can 
be removed with a sterilised needle and transferred to a fresh tube of jelly, 
and this can be repeated as many times as may be necessary till a perfectly 
pure growth of the fungus is established. If, after being planted for a 
few days, the scale is picked off the jelly, treated with potash as already 
indicated, and then placed under the microscope, it will be found that the 
ramifying hyphe described are in direct continuity with the fibres which were 
before stated to form the basis of the scales. 
The fungus grows even more quickly when kept at a temperature of 
90 degrees to 100 degrees Fahr. Sunlight, too, seems to stimulate its growth, 
and a considerable amount of moisture is also advantageous to it. Air (or 
oxygen) is necessary to it; it will not develop if planted at a depthin the 
jelly, and a layer of olive oil poured over it at once arrests its growth—a fact 
which explains the modus operandi of greasy applications in the treatment of 
affected horses. 
With a view of ascertaining if the fungus were capable of growing and 
producing mange in healthy horses, the following experiment was made :— 
The skin of a healthy horse was lightly scratched or scarified with a lancet in 
two situations, and a littie of the fungus, from a pure artificial culture, was 
then smeared over the spots. The scabs and scales, typical of horse mange, 
showed themselves on the parts thus inoculated ; and when, at the end of three 
weeks, small portions of these were examined miscroscopically, they were found 
to be made up of the same fungus, and artificial cultures were again established 
from them. The disease did not, however, appear to spread beyond the 
points inoculated, possibly because the weather at the time was cold and dry— 
* This is essentially a clear soup, made into a jelly with Agar-Agar (Japanese isinglass), 
