PROGRESS OF MICROSCOPICAL SCIENCE. 253 
He informs me that, though any conclusions now to be drawn from his 
observations must be provisional, it is safe to consider that many 
specimens of the Red Clay are so entirely analogous to what the 
Gault must originally have been, that those specimens might almost 
be looked upon as being as truly modern Gault as the Globigerina-ooze 
is modern Chalk. In the Gault the grains of fine sand are chiefly 
quartz derived from the decomposition of schistose rocks. But the 
Pacific and Atlantic muds from great depths contain, besides quartz 
fragments, others of glassy felspar, pumice, and other volcanic pro- 
ducts; and Mr. Sorby has not been able to detect any difference 
between the main mass of the Gault and other rocks which are com- 
posed of very minute granules like those derived from felspar or other 
minerals which, in a similar manner, easily undergo complete chemical 
decomposition. Independent, therefore, of the presence of different 
organic remains, and of the modern volcanic products, there is little or 
no difference between the Red-Clay deposits and some of the earlier 
stratified rocks.” 
Empusca musce.—On this subject a paper was lately read before 
the Quekett Club, and appears in the last number of the Journal, 
by Mr. T. Charters White. He said, among other things, that the 
characteristic appearance of a fly affected with this disease is best 
detected when the fly, in its last moments, settles on a window; it 
then may be recognized by a zone of white deposit surrounding the 
fly like a halo—the fly maintains its living attitude, and will be found 
attached solely by the lips of its proboscis. Its legs are not crossed 
under it as is the case with all dead insects, but distended, as in the 
live state. Examining the fly now externally, you will find the hairs 
covered with minute white globules. These are the spores of the 
fungus, and are scattered also round the fly for some distance, in a 
very curious manner; in some cases almost as if they had been 
squirted out of regular points of the body. ‘The abdominal rings are 
separated by about their own breadth from each other, while they seem 
bursting from over-distension. 'The thorax and head do not seem so 
much affected as the abdomen. On opening the fly in a little glycerine 
and water, the cause of this over-distension is soon discovered by the 
appearance of a dense mass of mycelium threads, that emerge as soon 
as an opening is made in the abdomen, On the termination of Mr, 
White’s paper, a few very sensible observations on it were made by 
Mr. W. W. Reeves, which we quote as follows. He suggested that 
Mr. White might have carried the subject further with greater ad- 
vantage, for if they wished to follow up the growth of this fungus 
they must not be content merely to watch it as found upon dead flies, 
this being only half its history. Let them drop the fly into water, 
and then see what would take place. In a short time they would see 
the fungus grow out and develop in a very beautiful manner. It never 
fully developed upon a window pane for want of sufficient moisture, 
but if this were supplied much more could be seen of its history. 
Very little was known about it, but if anyone wanted to become 
better acquainted with it, by placing a fly thus attacked in a little 
water its further growth might be readily studied. Like many of this 
