448 OPERATIONS—TRACHEOTOMY. 
ward, as shown in the previous engraving, then laid hold of, and, when 
firmly grasped, the excision ought to be perfected. 
A tube has to be worn afterward; this is put into the opening, and 
fastened in by means of a strap or tape passed round the neck. There are 
many tubes sold by the instrument makers for this purpose; the majority, 
however, are far too large. None should be beyond one inch in diame- 
ter. The horse only requires to inhale part of the air through the can- 
ula, the remainder coming, as before, through the larynx. A free space 
of one inch is, therefore, plenty to admit the deficient oxygen; for no 
auimal could live through an operation, were air, previous to its com- 
mencement or during its continuance, altogether excluded. 
The best instrument for hasty and temporary tracheotomy is the 
invention of Mr. T. W. Gowing, of Camden Town. To insert this can- 
ula no cartilage need be excised; a puncture is made with a knife 
MR. T. W. GOWING’S TRACHEOTOMY TUBE. 
A. The canula, with a shifting shield, armed with the pointed trocar. 
B. The trocar withdrawn from the canula. showing its peculiar construction. 
C. The canula fitted into the horse’s trachea, showing how the movable shield may be adapted, by 
means of a screw, to the size of the horse or the swollen condition of the parts. 
through the connecting medium of the tracheal rings, and through this 
puncture the tube is driven. It is of all use for temporary or immediate 
service, but obviously would not do for a continuance. 
The objection to tracheotomy, when designed to last for any period, is 
that the canula, by irritating the lining membrane of the larynx, is apt 
to provoke abscess, which impedes the breathing to a degree that destroys 
the life. The author has seen some fearful instances of this effect; but 
of all tubes, that invented by the French seems to be least open to this 
objection. 
