213 
of Edinburgh, Session 1873 - 74 . 
into the interior of the tube, and one end (e) of which communi- 
cated with the outside through the wall of the tube. Round the 
whole external surface of this U*shaped tube a spiral of copper 
wire was coiled, and the induction current from a coil giving |-inch 
sparks was passed between the external copper (/) to the internal 
platinum wire (e), so as to have the platinum wire in the interior 
of the tube as the negative pole. After the current of gas was 
ozonised by the passage of the induction current, it was washed 
by passing through a bulb-tube (c to the left of the U tube) con- 
taining caustic potash when air was employed, or water when pure 
oxygen was used, in order to eliminate any traces of nitrous and 
nitric acids. To the right of the U tube another bulb-tube (c) was 
placed containing pure sulphuric acid, for removing aqueous 
vapour from the air, or gas passed through it. By means of the 
gasometer, the volume of gas passing through the apparatus could 
be ascertained. 
2. Method of Experiment . — It was necessary, in the first place, 
to determine the action of ozone on the living animal imprisoned 
in an atmosphere containing a large proportion of ozone ; and, in 
the second, to determine What action, if any, it exerted on the indi- 
vidual living tissues of the body. 
Observations were made on frogs, birds, mice, rabbits, and on 
ourselves. 
Frogs . — Numerous experiments were made on frogs, and the 
general effect on these animals is as follows : — About thirty seconds 
after introducing the animal into the chamber, through which a 
steady current of ozonised air was passing, the animal manifested 
symptoms of distress. The eyeballs were retracted, so as to be 
deeply sunk in the orbits, and the eyelids were firmly closed. It 
rubbed its nose occasionally with its fore paw r s. At first somewhat 
restless, the frog became lethargic, and the movements of respira- 
tion were reduced, both in frequency and force, to at least one- 
half the normal amount. On pushing the frog with a wire it 
might be excited to move, but usually it remained motionless. The 
position of the animal was peculiar — the neck arched, the head 
flattened, and it remained in a crouching attitude. This condition 
of lethargy has been observed to continue during a period of an 
hour and a half, at the end of which time the animal died. When 
