312 
FRANK H. MILLER. 
retaining them in that position by means of the ‘‘ net,” allow of 
a perfect evaporation of all moisture. 
Eczema of the ear, as of other parts of the body, can and 
does arise from the most diverse causes, but for the purpose of 
this article I will confine my remarks to those cases which from 
choice the writers describe as due to “ filth,” and group them 
under one head as due to chemical irritation. 
When a case is presented for treatment I invariably make 
chemical as well as physical examination in connection with 
the history ; indeed I have come to feel that a correct diagnosis 
and prognosis depends almost entirely upon the former. 
After examining the organ, both with and without the 
speculum, I test the secretion with litmus paper, and nearly 
always find a more or less strong alkaline reaction, invariably 
due to the presence of free ammonia. This latter I determine 
by making use of Eber’s admirable test as used throughout 
Europe, for computing the degree of decomposition in meats, 
before such can be detected by change in color or odor. 
This test is extremely simple of application and of inestima¬ 
ble value, consisting of one part chemically pure hydrochloric 
acid, one part sulphuric ether and three parts alcohol. 
The only requirements for its application is an ordinary test 
tube, perfectly clean and of medium calibre, and a glass rod. 
It is used by pouring a few c.c. of the fluid into the tube, 
which should be at approximately the same temperature as the 
testing fluid ; shake quietly about that the sides of the tube may 
become moistened and pour off again. While the tube is still 
wet, smear the tip of the rod in the secretions from the ear and 
carry it carefully down the tube almost to its bottom, avoiding 
touching the sides if possible. If free ammonia be present in 
the slightest quantity, a white vapor will in a very few moments 
settle down in the tube. 
The micro-organisms which figure in this diseased condition 
bring about their irritation to the tissues by splitting up the 
nitrogenous materials (filth) and liberating an irritating gas 
rather than by producing a specific poison, having the power in 
