142 
POPULAR SCIENCE NEWS. 
[S 
EPTEMBER, 
1890. 
of work which can be accomplished wilh the 
complete instrument, and the more perfect and 
satisfactory it will be. In considering the various 
parts of the^tand, the following illustration of the 
Griffith Club Microscope will serve to make them 
clear. 
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The hase, or lower portion of the stand, first 
attracts our attention. Instruments can be found 
with bases of almost all conceivable forms, but the 
only one suitable for druggists is the tripod. 
The fett forming the tripod may be disguised 
in the form of the base; but that does not matter, 
so long as there are three, and only three, points 
of support. This not only gives the greatest 
stability to the instrument, with the least tendency 
to vibrate when the table is jarred, but also has 
other advantages. One of these feet should always 
point toward the observer. This is of importance 
to the pharmacist, who has frequent occasion to 
incline the instrument while measuring or drawing 
objects by means of the camera lucida. The only 
exception to this is when the tripod has two long 
feet, as shown in the extra foot of the above illustra- 
tion. In such a case it is justifiable to have the 
short foot directed from the observer. 
The pillar., or support, requires no special atten- 
tion. With some instruments it is single, while 
others have a double support, so that the mirror 
bar swings between them. Pharmacists are not 
especially interested in either of them. 
The joint seen at the upper end of the pillar is a 
feature of more importance, and every pharmacist 
should see that his instrument can be inclined to 
any desired angle. If it is required that the instru- 
ment be used upright, it can be so employed just as 
well as the stiff-backed ones that we still see in the 
market. However, it is seldom that a druggist has 
occasion to use an instrument in that awkward 
position. This joint is usually a single hinge, but 
it may be secured by means of trunnions, and in 
such cases is usually provided with some means 
of tightening or loosening the bearings. Some 
instruments can be locked with the body at any 
desirable angle. This, however, is not necessary 
for a pharmacist's use. 
The arm is not very prominent in our illustration. 
It is the portion above the joint, and bears the body. 
In some instruments it is prominent, and closely 
resembles in form the flexed human arm. If it 
supports the body firmly, that is all that is required. 
The body is supported by the arm, and has 
attached directly to it the optical parts of the 
compound microscope. The body varies in size 
and length in different instruments. The size is 
not of very much importance, but in length it 
should be what is known as "standard," or be so 
arranged that it can be lengthened out. The body 
must be perfectly black inside, and this is best 
accomplished by means of black cloth. Cloth is 
more permanent than the blackened metal surface. 
The draw tube is found only in the better class 
of instruments, and is a provision for adjusting the 
length of the body. With very high power objec- 
tives it is very essential to have a draw tube. It 
should be marked to indicate when the body is 
"standard" length. A great convenience is a 
"society screw" in the lower end of the draw tube. 
Pharmacists have frequent occasion to use quite low 
powers, and if the low power objective is placed in 
the draw tube there will be plenty of working 
distance, which I have found is not the case with 
some instruments. Again, it enables the pharma- 
cist to place the analyser of the polaroscope in the 
draw tube wiien there is no working distance for it 
with low powers. 
The collar is the ornamental ring, or projection, 
at the upper end of the draw tube, or of the body 
when there is no draw tube. It is unimportant to 
the pharmacist. 
The nose piece is the portion at the lower end 
of the body. It is provided with a female screw, 
into whicli the objective is fastened. By all means 
purchase a microscope with what is known as 
the " society screw," so that any ordinary objectives 
can be fitted to it. I have found that the English 
thread in the " society screw" is not quite the same 
as the American, and I was obliged to get an 
adapter for the use of English objectives on an 
American stand. This nose piece has nothing to 
do with the double, triple, and quadruple nose 
pieces, wl\ich are accessories, and not a part of the 
stand. 
The stage is of importance. The best for the use 
of pharmacists are made of glass, so that they are 
not affected by liquids or chemicals. It is an item 
to have a thin stage which admits of oblique illumi- 
nation in the examination of crystals. The expen- 
sive mechanical stages are very convenient, but not 
essential for the use of a drug clerk. 
The sub-stage must be so arranged that it will 
admit of the use of sub-stage condenser, polari- 
scope, etc. It is hardly worth while for a pharma- 
cist who expects to do much work to purchase a 
stand without a sub-stage. 
The diaphragm is a contrivance for regulating 
the volume of light which is admitted to the object. 
When a sub-stage is present, the diaphragm is 
adjusted to it; othervvise it is attached to the stage 
in place -of the sub-stage. 
The mirror bar and its arrangement is plainly 
shown in the illustration. All modern microscope 
stands have the mirror bar so attached that the 
mirror can be raised above the stage for the illumi- 
nation of opaque objects. This is a great con- 
venience for the pharmacist who has many sub- 
stances to examine by reflected light. .It is best to 
have a mirror bar which can be lengthened or 
shortened as may be required. 
The mirror, if single, must be a concave one. 
Where there are two, one is plain and the other 
concave. As far as the plain mirror is concerned, 
the size does not make much difiference, but the 
larger the concave mirror the better. Pharmacists 
can use any mirror adapted to ordinary work. 
The clips are for holding the slide in position. 
The ones which can- be removed are preferable for a 
pharmacist who occasionally has liquids to examine, 
when the clips are in the way unless removed. 
The coarse adjustment is found on all instruments. 
The rack and pinion arrangement is the best, and is 
the one used on the better class of instruments. 
The fine adjustment, or m,icrometer screw, is also a 
feature of the better instruments, and should be 
present on every one owned by a pharmacist who 
intends to do much work. It is much more con- 
venient to have the fine adjustment near the coarse 
one. By all means avoid the instruments with the 
line adjustment on the body near the nose piece. 
They are inconvenient, and the use of them has a 
tendency to vibrate the body of the instrument. 
As stated above, the ocular, or eye piece, and the 
objective do not belong to the stand, so I \yill not 
consider them here. The lamp and attachment, as 
well as the turn-table, shown in the illustration, are 
accessories which require special description, not in 
place at this time. 
INCREASING THE MOBILITY AND POWER 
OF THE MUSICIANS RING-FINGER. 
A PAPER by Dr. F. \V. Langdon, in the Cincin- 
nati Lancet Clinic, discussed the above problem as 
follows : 
"The limited range of independent extension pos- 
sessed by the fourth digit of the hand is well 
known, and is usually a most formidable stumbling- 
block to the pianist and other performers on keyed 
instruments, in the production of certain notes and 
musical effects, as trills, for example. 
"The causes of this impairment of mobiliiy, 
which is associated with a corresponding lack of 
power in the digit, are two in number, namely: (i) 
mechanical, due to structural peculiarities of the 
parts; and (2) physiological, due to insufficiency 
of muscular development ; the lattei being depend- 
ent on the former. 
"The mechanical obstacles to free extension, as 
any one may satisfy himself by dissection, or even 
by examination of the average living hand, are two 
oblique tendinous bands, situated about three-quar- 
ters of an inch above the knuckle line, connected 
proximally with the common extensor tendon of 
the ring-finger and distally with the common ex- 
tensor tendons on either side, namely : those to the 
middle and little fingers. 
" That the subsidiary tendons act as 'guy ropes,' 
and limit the extensor range of the ring-finger es- 
pecially, may be determined by any one for himself, 
by placing the hand on a fiat surface and extending, 
first, the ring-finger alone; then extension of its 
neighbors on either side will demonstrate that all 
three can be brought higher than either one alone. 
The little finger is seen to be less aftected than 
either of the others, owing to its possession of a 
proper extensor, which is free, while the middle 
finger is less limited than the ring, by reason of 
having the ' guy' tendon on one side only. 
" These diagonal tendinous bands are constantly 
present, though varying somewhat in development 
and position in different persons. 
" Not only is extension of the ring-finger dimin- 
ished, but separation of the three inner digits is 
materially lessened by the presence of these appar- 
ently insignificaiit slips, so that the lateral spread 
of the digits is impaired to such a degree as to be- 
come an important matter to the musician. Again, 
in addition to the mere limited range of motion, 
both vertically and laterally, due to the mechanical 
effects of these slips, there is also to be considered 
the physiological factor, namely-, lessened functional 
activity and consequently faulty development of the 
muscular fibres acting on the extensor tendon of the 
ring-finger, namely, fibres of the common extensor, 
fourth dorsal interosseous and third lumbricalis. 
This fault of development is a more important 
matter than would appear at first glance, since it is 
mainly by the interossei and hunbricales that the 
first phalanges are flexed and the second and tliird 
extended, whence the name ' fidicinales.'" 
The performance of the operation in one case is 
thus described: "The field of operation was pre- 
pared by thorough cleansing. The skin, with a 
large branch of the dorsal venous arch, was now 
slipped aside with the thumb, so as to leave clear 
of vessels the interspace between the third and 
