838 
A. VACHETTI. 
on top of the phonendoscope the circular disk B, which is also 
covered with a sheet of ebony. In order to examine a very 
limited point, for instance, a cardiac orifice, a limited part of 
the lungs, or in case of fractures, in order to make an auscultatory 
percussion or to define exactly the area of an intestine, one only 
has to screw the little metallic rod (A) to the centre of the 
disk B and press the ebony button on the part to be examined. 
The disk which receives the waves of sound can be applied 
simply with its sheet of ebony to the surface where the auscul¬ 
tation is to be made, if the surface is horizontal; but it is always 
better to press the surfaces well against each other with one 
hand, which is indispensable when the parts under examination 
are not horizontal. One hand of the examiner is free and the 
length of the elastic tubes permits him to remain at a certain 
distance from the auscultatory surface and from the patient, 
which is convenient and pleasant for both. 
Or, one can let an assistant compress the disk and the prac¬ 
titioner has both hands free for any emergency, and especially 
to make auscultatory percussion. One must always avoid the 
friction of the instrument and of the tubes against each other ; 
otherwise the noise caused by it would disturb the auscultation. 
I have repeatedly asserted that the best way to hear short 
sounds and murmurs, for instance, those of the heart, is with both 
ears. For prolonged murmurs and sounds, such as the breathing, 
the respiratory murmur and others, it is better with one ear 
only. But the phonendoscope renders it very easy to examine 
with one or both ears, according to what is most indicated. 
The apparatus of the Professors Banzi and Bianchi, which I 
have applied several times to persons and animals, is very valu¬ 
able for schools as well as in the practice, because it permits 
two persons a simultaneous auscultation on the same point, 
each of them using one auscultatory tube, and therefore it is of 
greatest advantage in semiotic lessons and in consultations.' 
As it increases the sounds, it is a real resource for hard- 
hearing people ; therefore we can also consider it an excellent 
acoustic ear-trumpet. 
