146 
POPULAR SCIENCE NEWS. 
[October, 1S90. 
the composition, structure, anil properties of 
a substance which few chemists have ever 
A CURIOUS TREE. 
{Draccena Draco J) 
The accompanying engraving of this rare 
tree is taken from a photograph — made for 
La Nature — of one of the few specimens 
naturalized in Europe, and growing in the 
gardens of one of the royal palaces of Portu- 
gal. It is probably about 250 years old, 
dating from the time when the species was 
first introduced into Europe. 
The head of the specimen illustrated meas- 
ures 115 feet in circumference, and begins 
about seven feet above the ground. The 
thickness o'f the trunk is often equal to the 
height of the tree. The leaves, growing in 
terminal bunches, are about two feet long 
and one to two 
inches wide, termi- 
nated by a sharp 
point. The green- 
ish - white flowers 
are borne in loose 
terminal panicles. 
The most impor- 
tant product of the 
plant, however, is 
the red gum which 
exudes from the 
trunk, and forms 
one of the several 
kinds of dragon's- 
blood of the drug- 
gists. 
The Draccena is 
a native of the East 
Indies, and only 
thrives in Europe 
in exceptionally fa- 
Vorable situations. 
Probably the warm- 
erclimate of certain 
parts of this coun- 
try would allow it to be easily naturalized 
and become an acceptable addition to our flora, 
both for purposes of ornament, and as a source 
of supply of a valuable ingredient of paints 
and varnishes. 
f'eesional worker; on the other, that among an 
assembly of professional workers the amateur and 
the beginner would be out of place. For either 
of these prejudices the best cure is attendance at one 
of the annual meetings. But as the opportunity 
has passed for this year, a short sketch of the meet-, 
ing held in Detroit during the second week of the 
past August may contribute to more just views 
concerning the work of the society. 
There were there gathered together some fifty 
persons of intense earnestness. Among them were 
pnicticing physicians, professors of biology, chem- 
ists, men from agricultural experiment stations, 
experts, opticians, and a few — too few — whose 
acquaintance with the microscope was limited and 
recent. If any readers are in this last position, let 
it be urged upon them to identify themselves with 
the society. The consideration and generosity 
of the older workers is unbounded. The beginner 
is welcomed into their midst, and in three days 
learns more than he can in three months of solitary 
study. 
The microscope being an instrument of the high- 
[Original in' Popular Science A'ews.] 
WITH THE MICROSCOPES AT DETROIT. 
BY KATHARINE B. CLAYPOLE. 
It is now thirteen years since a few microscopists 
met together and formed the American Microscopical 
Society. Since that time annual meetings have 
been held in various cities of the Union, and interest 
in the proceedings has steadily increased. Never- 
theless, considering the number of microscopes in 
daily use among professional men and amateurs, 
the membership of the society is far smaller than it 
should be. Two opinions, diametrically opposed, 
though equally erroneous, contribute to this result : 
On the one hand it is held that the society is only 
for amateurs, and that nothing is likely to be 
brought forward worthy of the attention of a pro- 
est complexity, and all success in its use depending 
on the nicest adjustment of all its parts, it is natural 
that its mechanism should occupy a large part of the 
attention of the society. Many and vigorous were the 
formal discussions concerning the means of obtain- 
ing the full capacity of the instrument; while those 
carried on around the fine microscopes and accesso- 
ries displayed by the leading makers of America 
were so engrossing that the first business of every 
session was to summon the members congregated in 
the exhibition room. 
The use of the microscope in biological inquiry 
was well illustrated by papers giving the results 
of much patient work in animal and vegetable his- 
tology. Some physiological subjects were treated, 
as also matters pertaining to the mounting of objects, 
and to the imbedding, slicing, and staining of tis- 
sues. The representation of the society at the 
World's Fair at Chicago in 1893, and the fees 
of experts with the microscope, drew forth a lively 
exchange of opinions. An important communica- 
tion was presented on the microscope and camera in 
the detection of forgery, showing clearly how little 
chance there is for a false signature to escape detec- 
tion when once submitted to the test of these 
instruments. The discussion of greatest general 
interest was introduced by a review of some of the 
medico-legal questions involved in the Cronin case. 
The experts, both for prosecution and defence, were 
present, and in giving the reasons that had led 
them to such opposite convictions, they showed the 
immense amount of experimental work on which 
these convictions were based. At the same time it 
was clearly brought out that vast ignorance exists 
concerning what a microscope can and cannot do in 
the determination of spots of blood, fragments of 
hair, etc. A committee was therefore formed to 
prepare a report which should serve as a basis 
of information regarding the nature of testimony 
which, at present, can be expected from a conscien- 
tious microscope expert. 
The work of the session was relieved one morning 
by projections on a screen of some of the more 
interesting objects brought by members of the 
society. A magnification of signatures lately fig- 
uring in a forgery case made clear the points by 
which the false had 
been detected from the 
true. Projections of 
photographs taken 
with the crystallinL 
lens of a calf and with 
the compound eye of a 
beetle, were a valuable 
contribution to our 
knowledge of the 
world as it appears to 
our poor relations. 
The picture that would 
be formed on the ret- 
ina of a calf is much 
the .same as that which 
reaches our own, the 
outlines being a little 
more blurred and the 
figure slightly dim- 
mer. As for the 
beetle, the rays that 
pass through the lens 
of any one of his eyes 
carry an image of sin- 
gularly sharp and 
wtll-dcfined outlines. 
The difficulty in this 
case is the number 
of these images, the 
200 projected on the screen representing but a small 
part of all those formed by the wonderful complex 
beetle-eye. A comparison was also made of the 
blood taken from the thigh of Kemmler — the mur- 
derer who recently sufl^ered the penalty of the law 
by electrocution— with that from his forehead. The 
former showed the corpuscles unchanged, while 
those of the latter were compressed and somewhat 
distorted. Dr. George Fell, President of the 
society, took this eflect of electricity on protoplasm 
as the theme of his address, in the course of which 
he detailed the careful experiments on which the 
mode of applying the electricity had been evolved. 
He also condemned the sensational accounts that 
have been given of the event, s.iying that in his 
opinion— and he was present— death was almost 
instantaneous and entirely painless. 
It is the custom of the society to give the after- 
noon of one day to a working session. This, to 
many, is the most profitable part of the meetin"^. 
Skilful manipulators sit at their tables and give 
practical demonstrations of the part of microscopic 
technique with which they are most familiar. The 
