THE EXACT MEASUREMENT 
OF THE ELECTRIC CURRENT, AND OTHER 
PRACTICAL POINTS IN 
The Destruction of Hair by 
Electrolysis, 
With Especial Reference to the Use of the 
ABSOLUTE GALVANOMETER. 
BY 
MORTON PRINCE, M.D., 
Physician for Nervous Diseases to Out-Patients, Boston City Hospital. 
[.Reprinted from the Boston Medical and Surgical Journal 
of November 4, 1886.] 
BOSTON : 
CUPPLES, UPHAM & CO., Publishers, 
©Hi (Corner Book Store. 
1886. ON THE EXACT MEASUREMENT OF THE ELEC- 
TRIC-CURRENT AND OTHER PRACTICAL 
POINTS IN THE DESTRUCTION OF HAIR 
BY ELECTROLYSIS, WITH ESPECIAL REF- 
ERENCE TO THE USE OF THE ABSOLUTE 
GALVANOMETER. 
BY MORTON PRINCE, M.D., 
Physician for Nervous Diseases to Out-Patients, Boston City Hospital. 
To remove hair by electrolysis is a very easy opera- 
tion, but it is not so easy to do it without leaving be- 
hind disfigurements, either temporary or permanent. 
One of the disadvantages connected with the process 
is the dermatitis which is apt to follow the operation, to 
say nothing of the more severe papular inflammations, 
and not infrequent ulceration of the hair-follicles. 
Worse still, because permanent, are the scars. The 
latter, to be sure, even on a woman’s face, are a small dis- 
figurement, excepting when the process has been badly 
done, compared to that caused by unsightly hairs; 
still, they are scars. The dermatitis, to be sure, is 
only temporary, lasting only a few days, but while it 
lasts the skin is sore, and the face decidedly disfig- 
ured. The small ulcerations of the hair-follicles, 
small as they are, are of more importance, as they 
lead to comparatively large scars, instead of the almost 
invisible cicatrices left, if any at all develop, by the 
process when properly done. It should be stated, 
however, that even minute cicatrices are not a neces- 
sary result. 
It is generally stated by those having experience 
with the operation, that these ill effects are dependent 
upon the peculiarities of the individual skin, some skins 
bearing the operation without any bad after-effects, 
while others are easily inflamed. While there is con- 
siderable truth in this, and there is 2 
in the capacity of different parts of the skin of the 
same face to bear electrical currents without inflamma- 
tory reaction, still 1 have long suspected that the 
greater part of the difficulty is due to the intentional 
or unintentional use of excessively strong currents, 
and that such unintentional use is due partly to the 
fact that no proper means are employed to measure 
the strength of the current, and partly to the fact that 
a current from a given number of cells varies immensely 
in strength during the course of a single sitting, owing 
to the varying resistance offered by the skin. To over- 
come the undesirable effects which are consequences 
of these difficulties, I have hitherto advocated using 
the weakest currents possible, preferring to have more 
hairs come back to be operated upon again, rather 
than run the risks of pustules and disfiguring scars. 
Though secondary inflammation and cicatrices have 
in this way been mostly avoided, still the operation 
has been beset with great annoyances, such as the 
sudden weakening of the current below the strength 
practically necessary for the destruction of the hair 
papilla, with consequent imperfect results, necessitat- 
ing tedious fussing with the battery, while again, 
the strength of the current may suddenly rise, for 
various reasons, above the required point, etc., etc. 
It was not till I began using the absolute galvano- 
meter that I found a practical method of gauging 
the strength of the current, nor till then did 1 ap- 
preciate the extent of the fluctuations that may oc- 
cur in the current strength in the course of a single 
sitting. Nothing is more uncertain and useless than 
the methods usually recommended by those who 
practise the operation for determining the strength 
of the current. Every writer on the operation, that 
1 have seen, directs either that so many cells be used, 
or that a current sufficient to produce effervescence 
at the needle be employed. 3 
Now, for reasons that will be presently explained, 
a most powerful current—one sufficient to produce 
severe destruction of tissue — may be unwittingly used 
without effervescence occurring, and in thesecond place, 
with the same 'number of cells, the current may vary 
five-fold, at least. It has been long known to electro- 
therapeutists that the number of cells, even aside from 
the difference in strength of the cells of different forms 
of batteries, is no guide whatever to the strength of 
the current. Another factor, besides the electro-motive 
force of the cells, must be taken into consideration, 
namely, the resistance to be overcome. This varies 
immensely, according to the size and construction 
of the electrodes, the degree of pressure with which 
they are applied to the body, the condition of the skin, 
its dryness or moistness, the portion of the body to 
which the electrode is applied, etc., etc. That 
these are no theoretical difficulties, but practical ones, 
may be seen by the results obtained in the following 
experiment: A current from the same number of cells 
was applied through the same electrodes, thoroughly 
wet at each application. The resistance of the skin 
over the spine had previously been reduced to a mini- 
mum by prolonged applications. 
1. One electrode over palm, other over back of hand. 
Current = 2 Milliamperes. 
2. One over spine, other over palm. “ 2 “ 
SS. One over spine, other over hack of hand. “ 6 “ 
4. One over each lateral half of back. “ 8 “ 
5. One over spine, other over forearm (front) “ 9 “ 
6. One over front, other over back of forearm “ 9 “ 
7. One over spine, other over hack of forearm “ 10 “ 
8. Both ever spine. “ 10 “ 
9. One behind each trochanter. “ 11 “ 
Or, in other words, with the same given number of 
cells and the same electrodes, the current may be 
increased from two to five times, according to the 
different location of the electrodes in the same indi- 
vidual. , 4 
Again, with the positive electrode over the back or 
front of the forearm, negative on some part of the face, 
the current frequently varies, in the experience of the 
writer, between one and three milliamperes, though 
the sqme number of cells be used, according as the 
needle is inserted in different parts of the same face. 
The same thing happens, as would naturally he ex- 
pected, with a current from the same number of cells 
applied to different persons, though the conditions be 
made as far as possible alike. 1 have found that after 
taking all possible precautions to apply the poles to 
the same regions, and after reducing the resistance of 
the skin to the minimum, that from twice to three 
times as strong a current may pass through one person 
as through another, though the same number of cells 
be used. Again, the fluctuations in the current strength 
dependent upon the size of electrodes may be seen from 
the following experiment: 
The same number of cells were used in each case, 
and the electrodes applied to the same region of the 
body, namely, the thighs. The electrodes were of 
five sizes, No. 1 being the smallest, and about the size 
of the top of a slate pencil. The largest. No. 5, 
measured 3x6 inches, but the whole surface was 
not in complete contrast. 
With electrodes No. 2 and No. 1, current = 3 Milliamp6res. 
“ No. 2 “ No. 3, “ = (i 
“ No. 2 “ No. 4, “ = 7 “ 
“ No. 2 “ No. 5, “ = 9 “ 
“ No. 5 “ No. 5, “ =tt “ 
“ No. 5 " No. 1, “ = 6 “ 
To show how useless is effervescence as a guide, the 
following experience (of frequent occurrence) jotted 
down at the time, will show. The writer was remov- 
ing from the neck some fine hairs, which grew at a 
very acute angle with the skin, and, therefore, some- 
what difficult to destroy. After applying the current 
for the usual length of time, the hairs were found to 5 
be still firmly attached and no effervescence had 
occurred. The natural impulse would have been to 
increase the current, but a glance at the galvanometer 
showed that a current of three milliamperes was pass- 
ing— three times as strong as was necessary. The 
fault lay in an inaccurate direction given to the needle, 
and the inability of the gases to escape to cause 
effervescence. 
Furthermore, effervescence is not necessary for the 
destruction of the hair bulb. Hairs can be destroyed, 
as I have repeatedly demonstrated, without the slight- 
est appearance of effervescence. 
The variations in the current-strength caused, even, 
by different modes of applying the electrodes to the 
skin may be seen from the following : 
Twelve cells were used. A large electrode, X 
inches, was applied to the forearm, while a small 
electrode, inches in diameter was successively 
applied, first, to the centre of palm of hand so that 
only one surface was in contact with skin ; second, 
between the thumb and palm so as to be held by pres- 
sure of the thumb; and third, to the centre of 
palm but grasped by the fingers. In this way the 
amount of surface in contact was successively in- 
creased. The strength of current obtained was as 
follows : 
1st Method J Milliamp. 
2d “ i “ 
3d “ 1 “ 
The following experiment was undertaken to show 
the variations in current-strength due to variations in 
size of the positive electrode in conjunction with a 
needle inserted into a hair follicle for electrolytic 
purposes. 
1. Small electrode. (1J inch) to palm .... } Milliamp. 
2. “ “ “ grasped . . . . J “ 
3. “ “ “ to forearm . . . . ll “ 
4. Large electrodes, in.) to palm . . . . l| “ 
6. “ “ ' “ “ to forearm . £ “ 6 
In other words, the large electrode applied to palm 
gave six times as strong a current as the small elec- 
trode, etc. 
One more experiment shows the different results ob- 
tained by electrodes of different sizes, construction 
and conditions of moisture used in conjunction with 
the electrolytic needle. 
Electrode covered with cotton. 
1 in. diam. 
Electrode covered with 
sponge. 2 in. diam. 
1. To palm . . i Milliamp 1 Milliarap. 
2. To forearm . 1 “ .... 2-3 “ 
3. To palm . . sponge allowed to become com-1 , ,, 
paratively dry. ) * 
Here it will be seen that the current obtained with 
a sponge electrode, after the water had been squeezed 
out, as always happens after a few minutes use, was 
reduced one-half. 
It should be stated that the smaller electrode was a 
polished copper disc covered with absorbent cotton, 
one of the best conductors. While the large one was 
covered with chamois-skin, and its metallic surface, as 
I afterwards discovered, was corroded and covered 
with verdigris, consequently its conducting power must 
have been greatly impaired. I suspect that if it had 
been constructed like the smaller one the differences 
would have been still more marked. It should be 
mentioned that the resistance of the skin in these ex- 
periments was reduced to a minimum by the usual 
methods. 
A variation in the strength of the current may 
even be produced by the needle not being inserted to 
the same depth in the skin. I have seen the current 
doubled from this cause. 
Under these conditions, then, it cannot be won- 
dered at that the effects of electrolysis are uncertain, 
sometimes resulting in dermatitis and scars, and some- 
times in destruction of the hair alone, without the 
slightest disfigurement. It must be apparent to any 7 
one that, to get the best results from electrolysis, we 
must have some accurate method of measuring and 
regulating the strength of the current. This can be 
done by means of tbe absolute galvanometer, which, I 
have found, answers every purpose, and which I now 
always use. By its means the current can be accu- 
rately and easily regulated, and any fluctuation in its 
strength immediately detected. Discovering the fluc- 
tuation, it is easy to determine the cause, and to guard 
against its reoccurrence. The practical results ob- 
tained I have found to be far better than formerly. 
Pustules can be wholly and cicatrices almost entirely, 
even if not absolutely, avoided. When one has once 
used such an instrument, providing he has a reliable 
one, he will be loth to give it up. No small advan- 
tage is that one learns the conditions essential for a 
steady current, and is thus able to prevent variations. 
An increase of one milliampere in ordinary electro- 
therapeutics is of no consequence, but in such delicate 
operations as electrolysis, it is of the greatest conse- 
quence. A case in point will illustrate these advantages. 
It is that of a young girl who had a very abundant 
growth of hair upon her face, necessitating repeated 
operations, extending on and off over a space of two 
years. It so happened that the skin under her jaw 
was very sensitive to electricity, so that electrolysis 
was always followed there by more or less inflammation 
and scars, be as careful as I would. In contrast, to this, 
on the sides of her face, she could bear comparatively 
strong and repeated currents with immunity. Under 
the jaw, on the other hand, only very few hairs could 
be done at a sitting, and that with very mild 
’currents. Pustules, dermatitis and fine scars were 
frequent effects. Since using the absolute galvano- 
meter all this has changed. I can now do what 
remains to be done without any secondary inflamma- 
tion, and so far as I can see without any scars what- 8 
ever. And I believe it to be theoretically possible to 
always remove hairs without scars. Practically it is 
dillicult because the requisites are absolute care and 
great physical endurance on the part of the operator. 
The endeavor should be to direct the action of the 
current, as far as possible, to the hair bulb and follicle 
alone. This can only be approximated by accurately 
inserting the needle and using the weakest currents 
for the shortest period compatible with effective prac- 
tical results. 
But supposing an absolute galvanometer is to be 
employed, what rules should be observed in perform- 
ing the operation; what strength of current should be 
employed, and for what length of time ? The direc- 
tions laid down by most writers are most indefinite, 
and do not show an intimate knowledge of either the- 
oretical or applied principles of electricity. A late 
English writer, whose article lies before me and 
whom I quote merely to bring out the [joints 1 wish 
to enforce, gives the following directions: a battery 
of from ten to fifteen cells is to be used; the current 
is to pass from ten to thirty seconds until slight froth- 
ing is produced or a wheal appears around the mouth 
of the follicle. It is also stated that it is not abso- 
lutely necessary that the needle should be inserted 
directly into the follicle, as the requisite destruction 
occurs if the instrument be in its immediate neighbor- 
hood, and that papules and pustules result, which 
remain visible for some weeks. 
That papules and pustules result under these cir- 
cumstances can scarcely be wondered at. There 
can scarcely be any better way of producing them, as 
well as scars, than some such method as this. 
The danger of relying upon the number of cells 
to determine the strength of the current has 
already been shown. Ten to thirty seconds is alto- 
gether too long for any current generated by ten to 9 
fifteen cells of a good working battery, unless a great 
resistance is offered by the circuit, which cannot he 
known without an absolute galvanometer; and, accord- 
ing to the experience of the writer, a wheal should never 
be produced. Any current which produces a wheal, 
especially one that is white and sharply circumscribed, 
is too strong. Furthermore, I believe it to he abso- 
lutely essential that the needle should he inserted 
directly into the follicle and through the papilla, 
but not beyond if possible, if cicatrices are to he 
avoided. 
.The writer has made numerous experiments to 
determine what strength and duration of current gives 
the best results. Before stating the specific conclu- 
sions arrived at, the following general principles may 
he laid down. The weakest possible current of the 
shortest possible duration compatible with efficiency 
in the time at the operator’s disposal should be used. 
If there is much work to he done, less time can he 
given to each individual hair. But the stronger the 
current and the longer its duration, the greater cer- 
tainty of after inflammation and scars. On the other 
hand, with very w< ak currents, say under one-half 
milliampere, the time requisite to destroy the hair-bulb 
is too long for practical purposes, especially if there 
is much to be done; for the stronger the current the 
shorter the time needed, and vice versa. As a matter 
of experience, and as the result of numerous observa- 
tions, I have found that a current of one milliampere, 
passing from two to three seconds, is the best. It 
should he not less than one-half nor more than two 
milliamperes. With one-half milliampere it can be 
easily done, but takes longer. Such a current is, 
perhaps, to he preferred if only a few hairs are to be 
destroyed. With more than two milliamperes pustules 
and scars are almost sure to result. It must be 
understood that the stronger the current, the shorter 10 
time must it be allowed to pass, and the greater the 
pain. 
My plan is always to watch the needle of the galva- 
nometer, and if itswings towards two milliamperes, to 
shorten the duration, and if it goes beyond two milli- 
amperes to immediately break the current. I do not 
mean to sav that it is impossible to use stronger cur- 
rents without causing bad after-effects, but it is very 
difficult to do so. and the current must be broken 
almost immediately after being made. With a current 
of one milliampere, thiee seconds is amply long 
enough for the current to flow. This 1 have 
repeatedly determined with watch in hand. If the 
hair be not destroyed in that time, the reason therefor 
will almost always be found to be that the needle has 
not been accurately introduced within the hair follicle 
so as to hit the bulb. 
Of course the stronger the current and the longer 
it be allowed to act the easier it is for the operator to 
successfully work, and hence there is always an in- 
ducement to use strong currents. If a current of one 
milliampere acting for three seconds will decompose the 
tissue within a radius of,' say, 1-50 inch, for example, 
a current of three milliamperes will decompose all the 
tissue within 3-50 inch, or thereabouts ; and therefore 
with the latter current much less care need be em- 
ployed in introducing the needle, as it has only to be 
placed somewhere near the hair, and till the neigh- 
boring tissue must succumb, hair and all, hence cica- 
trices. 
For this reason the needle should be accurately in- 
serted into the follicle and papilla. If it is placed 
simply in the neighborhood of the latter, till the in- 
tervening tissue must necessarily be exposed to the 
electrolytic action. Greater destruction of tissue 
than necessary will then be occasioned, and pustules 
and scars must result. 11 
Sponge electrodes are very undesirable, as their 
conducting power rapidly changes as tlie water be- 
comes squeezed out. 
There is one more practical point which should he 
mentioned. The patient should never he allowed to 
hold the positive electrode in the hand, as is usually 
advised. What between the great resistance offered 
by the palm of the hand involving the necessity of 
keeping the thick dry skin thoroughly soaked with 
water, and the unevenness with which a patient presses 
with the electrode, it is impossible to maintain any- 
thing like a steady current. If the current hurts, the 
patient is sure to let up on the electrode. Under such 
conditions I have sometimes found it impossible to do 
the operation at all, the galvanometer at times marking 
no current and then again jumping to three and four 
milliamperes. A large electrode, covered either with 
chamois-skin or a thin layer of absorbent cotton, not 
sponge, should be fastened to the forearm, as the 
most convenient place. It is hardly necessary to re- 
fer to the danger of using the positive instead of the 
negative pole in connection with the needle or destroy- 
ing at one sitting hairs situated close together, as 
these points have been referred to by other writers. 
The powerful electrolytic action of electricity on 
tissue, and the possible disastrous effects of strong and 
long continued currents may be seen from the follow- 
ing experiments, out of a number of others made by 
Dr. T. D. Davis,1 some time ago, in connection with 
another operation. The first experiment was made 
with a 30 cell Grenet battery, the second with a 15 
cell Bunsen battery. 
(1) Two steel needles, thickness of knitting needles, were in- 
troduced into the tissue of a healthy liver within half an inch 
of each other. Immediately afterwards bubbles of gas com- 
menced to issue from the cut surface of the liver, which was 
1 Philadelphia Med. Times, October 2, 1871. 12 
nearer to the points of the needles than the place of their in- 
troduction. In four minutes the needle connected with the 
negative pole became very loose, and hubbies of gas escaped 
around its point of entrance. In five minutes the needles were 
withdrawn, the negative one coming away easily, while the 
positive one, which was blackened and roughened, was firmly 
adherent. On cutting across the track of the negative needle, 
a cavity, one quarter by an eighth of an inch in diameter, was 
discovered, surrounded by a darkened gelatinous tissue, one- 
eiglith of an inch in thickness. Extending from this to the 
point where most of the gas escaped was a mass resembling 
that surrounding the cavity, looking more like softened glue 
than healthy tissue. The track of the positive pole was black 
and charred, hut the tissue immediately surrounding the point 
was firmer and whiter than in other parts. 
(2) A cat was put under the influence of chloroform and the 
needles were introduced into the right thigh one inch apart. 
Soon the fizzing sound was heard, which continued until the 
needles were withdrawn, at the end of ten minutes. The tissue 
was softened around the negative and much hardened around 
the positive needle. The needles were then introduced into the 
left thigh of the same animal, and retained there for ten min- 
utes. In the post-mortem examination, several days later, the 
skin on the right thigh was found ulcerated for an inch in di- 
ameter. The muscles were separated down to the heel hut not 
to the hone There was a cavity under the skin large enough 
to hold a walnut. The left thigh presented similar appearances, 
the cavity being as large as an egg, and the muscles separated 
down to the bone, as well as softened and eaten away. Part of 
the femur was denuded of periosteum, but not eroded. 
These, of course, are the effects of powerful cur- 
rents lon£ continued, but the action from weak cur- 
rents is the same in kind, differing only in degree, and 
these experiments show how it is possible to produce 
on the face irreparable injury unless care be used.