here. 
1907.] Influence of Increased Barometric Pressure on Man. 23 
Table X (13). 
Animal oe 
Re aa Sidirca cnn occ vasnas oes 8 
Lue fe eee Peete 11 
Cat and 4 kittens ............... 8—6 
Ete, hie s lie holds bdedeiee sds 8 
Atmospheres 
of O, (about 
90 per cent.). 
LL Ue eee 6 
oD Se 6 
MMs ctiss icadasccsesnscesntsese 6 
Li ree 6 
CMR Sted dy dornididewe:scaicdsaes 5 
MMI feats sic den 1a ene svdvonca snes 5—6 
UM Pasa do eo icin et va 59.00%, tng! an 64 
HEROES St eres Ses ace wedececesecee’ 6 
MIAN 05/4 pobistdn < d guinlna ase videolan sca 6 
MRR des dalsiw so. sore isd. ae Hebe ase 6 
4—5 
MMe iltes Vatdids cseexdyrgeayeds seeqos { - 
MME EERG Osten 2d Models sioner ois ue stone ne 5 
oe ee a a 43 
MMM A So ckaccatisenesencde ve 22 
PGES FAD DIG... sn sceeccssccecess ) 
MGUEES THOUS... ...00s0ccecrscccees | 2 
Small mouse (16 grammes) ...| > 42 
Large mouse (26 grammes) ...| | 
Small rat (50 grammes)......... J 
Period of 
exposure. 
Guan 
1 hr. 20 mins. 
1 hr. 40 mins. 
15—20 mins. 
Result. 
Pneumonia. 
Death. 
Pneumonia. 
Gasping respirations ; re- 
covered. 
Pneumonia. 
»? 
+B) 
” 
Convulsions. 
Nil. 
Convulsions. 
Nil. 
All the animals convulsed. 
In the case of the lungs the action of the oxygen is direct, and there is no 
reason to suppose that the size of the animals should have any influence 
As to the convulsions, Lorrain Smith (14) has shown that these are 
caused not by the amount of oxygen combined, but by the tension of 
oxygen dissolved in the blood. 
normal state. 
Convulsions are as readily produced in 
an animal whose blood is half saturated with carbon monoxide as in the 
The immediate factor in their causation is unknown... 
Conclusions. 
1. Small mammals are relatively immune from decompression effects. 
2. This immunity depends on rapidity of circulation, and may be destroyed 
by damaging the latter with chloroform. 
3. Age is probably important per se, but of far less importance than body 
weight. 
We have no convincing proof that two animals of the same weight 
but different ages would exhibit unequal resisting powers. 
4, There is no evidence that small animals are more quickly poisoned by 
high pressures of oxygen than large ones. 
