1897 THE MICROSCOPE. 47 
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liar, unsightly pimples and silver-like projections on the 
surface of the otherwise apparently healthy potatoes has 
been the subject of much comment and speculation, espec- 
ially by those potato growers living on Long Island, in 
which section of the State the disease is prevalent. Re- 
cent investigations and experiments on Long Island con- 
ducted by the N. Y. Agricultural Experiment Station have 
brought to light the previously undiscovered facts as to 
the cause of this disease. It appears that the real cause 
of this injury is the well-known black cucumber beetle 
a small, black, flea-like beetle—which, although commonly 
called the cucumber beetle, has proven that itis fully as 
fond of eating holes into the leaves of potato and tomato 
plants as it is of doing a similar mischief to the cucumber. 
But, although the beetles themselves are voracious 
feeders, they are not the immediate cause of the mischief. 
The female beetles lay the eggs which produce minute, 
slender white grubs. These burrow intothe tuber and 
cause the ‘pimples’? and their accompanying ‘‘slivers.”’ 
Thus there are two prominent characteristics of this dis- 
ease, namely: the ‘‘pimples”’ and the ‘‘slivers;’’ the one is 
probably the result of the irritation caused by the worm, 
while the other isa slender canalin whicha single grub 
may feed. An interesting peculiarity in this connection 
is that the ‘pimples’? may be found on the same tuber 
without the “slivers”? as well as the ‘“‘slivers’’ without the 
‘‘pimples.”’ 
Cement for Celluloid.—Celluloid may be firmly attached 
to wood, tin, etc., by using acement composed of two parts 
of shellac, three parts of spirits of camphor, and four parts 
- of strong alcohol. Keep closely corked. 
Rabies has increasedin England since the law relating to 
muzzles for dogs was repealed in 1892. ‘There were 38 
cases that year. In 1893 there were 93 instances; in 1894, 
248, in 1895, 672. 
Back Numbers.—We are furnishing the past fifty num- 
bers of this magazine (1893, 1894, 1895 and 1896) complete 
with four premium slides on receipt of four dollars, 
