144 THE NORTHERN MICROSCOPIST. 
becoming a moth of a silver grey color with a white spot on each 
side of the thorax. 
BRowWNIAN MoveMENTS.—At a recent meeting of the mounting 
class of the Manchester Microscopical Society, Mr. R. L. Mestayer 
exhibited a fluid mount of gamboge, showing that singular phe- 
nomenon known ‘as “molecular movement,” which all practical 
microscopists are acquainted with, but occasionally occurring under 
circumstances calculated to lead students astray in their inferences. 
This slide was put together fifteen years since, yet the particles of 
gamboge continue their course as merrily as ever. 
PHOTOGRAPHS OF Bacterta.—In the Photographic News for 
August, 1880, mention is made. of the photo-micrographs of 
Bacteria produced by Dr. Koch, in the following words :— 
“The photographs are transparencies executed in a most perfect 
manner, and capable of being thrown upon the screen at a lecture 
for instructional purposes. ‘They represent the animal tissue of 
mouse, rabbit, &c., after the animal had been punctured with a 
needle to permit the entrance of bacteria and the spread of blood 
poisoning. Let us examine the first of the series. Here are little 
round globules hanging thickly upon threads of cobweb, like tiny 
currants or grapes; they are the bacteria of the deadly gangrene, 
and as they advance all hope for the patient dies away. Here, in 
the next slide, is the articulated bacteria, like a tape worm or bit of 
jointed glass; and here the thin hair-like organisms that are the 
cause of relapsing fever. There are a score of pictures in Dr. 
Koch’s series, and they all have their vital—or shall we say deadly ? 
—history. ‘The spores of the bacteria are even more minute.” 
-REAPING HIS REWARD.—The following paragraph has been going 
the round of the Northern papers. If true, it does not say much 
for the liberality of the University which has not been backward in 
accepting the results of this poor man’s toil. 
“The extensive collection of botanical specimens gathered by 
John Duncan, the “ Alford weaver,” whose life was sketched in 
Good Words by Mr. Jolly, has been presented to the University of 
Aberdeen. It contains no less than 1,131 plants indigenous to 
Britain, many of which were obtained by their collector by moving 
about as a harvester over the southern districts of Scotland and 
the north of England. It is stated that this self-educated devotee 
of science, whose efforts recall those of Dick and Edwards, is now 
in his extreme old age dependent on parish relief.” 
EXHIBITION OF INSTRUMENTS.—The British Association will 
have an exhibition of scientific instruments during the forthcoming 
meeting at York. The object is to show, as far as possible, the 
progress which has been made during the past half century in the 
construction of instruments used in scientific research. 
