324 PROFESSOR DAVID HEPBURN ON 
the substance of the lung. The animal is known to have lived for some days, because it - 
was killed by poisoning with hydrocyaniec acid after an attempt had been made to rear 
it by artificial feeding. The carcase was preserved by injecting an arsenical solution. 
Neither of these processes would account for the absence of air from the lung tissue. 
We must therefore assume that either the natural elasticity of the lung tissue has pro- 
duced the condition noted, so that the expiratory apparatus of the animal is able to pro- 
duce a practical deflation of the lungs, which is doubtful; or that, partly owing to the 
length of time they have been preserved and partly owing to the preservative solutions, 
the air has practically all passed into solution and disappeared. ) 
A portion of the lung was prepared for microscopic examination, and, notwithstanding 
the number of years that have elapsed since the animal was embalmed, the different 
tissues were easily recognisable, but to staining agents such as hematoxylin and eosin 
they reacted very slowly and not very satisfactorily. 
The hyaline cartilage of the bronchioles was cellular, and very similar to the cartilage 
in the ear of the mouse. | 
The lobules of the lung were very clearly defined by interlobular tissue, which was 
continuous with the sub-pleural tissue, and throughout this tissue there was a well- 
marked amount of elastic fibres. 
All the air spaces were shrunken, 7.e. collapsed, almost to the point of obliteration, 
but they were free from exudation. ‘The capillary blood-vessels in the walls of the — 
air spaces were crowded with blood corpuscles, which may have been the result of the 
preservative injection. 
There is some reason, therefore, for considering that the normal elasticity of the lung 
in this seal was much greater than that of man, and that, consequently, the air would 
be much more effectively expelled from the lungs of the seal during expiratory move- 
ments. 
Attention may be drawn to certain of the body muscles whose attachments and dis- 
position were such as to add to their expiratory value. The panniculus carnosus muscle 
was a thin sheet enveloping the trunk from the hinder end of the abdomen to the face, 
and on the face and head forming a cowl modified for facial or expression muscles in 
relation to the various apertures in that region. ‘The fore limbs were in effect pushed 
through this axial sheet. The disposition of its fibres showed dorso-lateral and ventro- 
lateral directions, separated from each other by a lateral aponeurosis, and attached by 
aponeurotic fibres to the dorsal and ventral mesial lines such as may be seen in the 
porpoise, but less distinct. The direction of the muscle fibres in the dorso-lateral section 
was obliquely from before (cephalic) backwards (caudal), whereas in the ventro-lateral 
section their direction was obliquely from behind forwards. The general effect of the 
contraction of this sheet would be to expel the air from the very elastic and flexible 
thorax, as well as to compress the abdomen. 
The musculus obliquus abdominis externus showed no attachment to the ilium. 
By one end it was attached through digitations to the entire series of costal arches from 
