T II E 
Compound Microscope 
AS AN 
AID TO THE STUDY OF THE SKIN AND SKIN 
LESIONS IN SITU. 
BY 
HENRY G. PIFFARD, M. D„ 
Clinical Professor of Dermatology in the Medical Department of the University of the 
city of New York, etc. 
Reprinted from the Archives of Dermatology, Vol. I, No. 11, 
NEW YORK: 
G. P. PUTNAM’S SONS, 
4TH Ave. and 23D St, 
1875- THE 
Compound Microscope 
AS AN 
AID TO THE STUDY OF THE SKIN AND SKIN 
LESIONS IN SITU. 
BY 
HENRY G. PIFFARD, M. D„ 
Clinical Professor of Dermatology in the Medical Department of the University ot the 
city of New York, etc. 
Reprinted from the Archives of Dermatology, Vol. I, No. 11. 
NEW YORK: 
G. T. PUTNAM’S SONS, 
4'i'H Ave. and 23D St. 
1875. THE COMPOUND MICROSCOPE AS AN AID TO THE 
STUDY OF THE SKIN AND SKIN LESIONS 
IN SITU. 
HENRY G. PIFFARD, M. D. 
Clinical Professor of Dermatolology in the Medical Department of the 
University of the City of New York, etc. 
THE difficulties and inconveniences which surround the attempt 
to study the integumentary surface with the aid of the single 
lens or simple microscope are of such a character as absolutely to 
preclude the employment of lenses of high power. These difficul- 
ties are mainly the following: The shorter the focus of the lens 
employed the nearer it must approach the object, and conse- 
quently the amount of light that can be thrown upon the object 
is diminished, the field of view becomes contracted, and the spher- 
ical aberration becomes so evident as to materially jeopardize the 
accuracy of the result. Ido not deny the possibility of obtaining 
a simple lens free from this form of aberration, as I possess one 
made by Steinheil, of Munich, which is admirably corrected in this 
respect, but the great majority of simple lenses are uncorrected, and 
consequently give distorted images of the objects under examina- 
tion. In addition, the shorter the focus of the lens, the nearer 
must the eye of the observer be approached. This often involves 
a constrained position of the head and neck, tiresome to the ob- 
server, to say nothing of the unpleasantness of too close contact 
in some cases. 
To obviate these inconveniences and at the same time to obtain 
a comparatively high amplifying power became then a problem 
worthy an attempt at solution. After mucn fruitless experimentation I arrived at the appar- 
atus shown in the accompanying figure. 
A represents the body of a binocular 
microscope made by Natchet, from which 
the reflecting prism situated above the 
objective, was removed, and another of 
the same form but double the size sub- 
stituted. B is a double nose piece car- 
rying two objectives of different powers. 
C is the pinion for fine adjustment, and 
D the clamping screw for coarse adjust- 
ment. E is a rod five feet in length, 
which supports the other apparatus, and 
is itself supported by a cast-iron foot not 
shown in the drawing. Other adjust- 
ments permit the body of the microscope to be placed in a hori- 
zontal or any other desired position. 
The objectives which I employ are a 6", 2" and 1" of Grunow, 
a 4" and of Ross. The j-" is made with taper front, specially 
constructed for use with reflected light. 
The advantages of this arrangement over the single lens, are 
enlargement of the field of view, absence of spherical and chro- 
matic aberrations, convenient distance of the observer’s eye from 
the object observed, ten times the amplification practically attain- 
able with the simple microscope, and lastly the very great advan- 
tage of true stereoscopic vision. 
With the instrument described any portion of the integument 
from the scalp to the sole of the feet can be conveniently exam- 
ined, and a prolonged examination can be made without fatigue 
to the observer. 
The ordinary diffused light of a bright day affords ample illumi- 
nation with all the objectives except the . For this we need 
direct sunlight. If the examination be made at night or in a dark 
place, the light from a Tobold or other good illuminator, concen- trated upon the object with a mirror or bulls-eye condenser, will 
answer every purpose. 
It is not my intention now to enter into the results of obser- 
vations made with this instrument, but simply to suggest its use to 
those who desire a fuller acquaintance with surface aspect of 
the skin, or of skin lesions observed in situ.