520 ON THE REPRODUCTION OF THE NERVES. 
through the ductus arteriosus, of which I have spoken, and the 
rest ramifies through the substance of the lungs for their support, 
as well as to keep them pervious. Having done this, what re- 
mains is returned by the pulmonary veins to the left auricle, 
where it mixes with the blood coming from the posterior cava, 
and is replenished and revivified for the performance of its pro- 
per functions. 
The physiology of this peculiarity of structure in the heart and 
vessels immediately connected with it, appears evident. Had 
there been no foramen ovale, the blood going to the anterior ex- 
tremities would have been of the most impure kind, not having 
undergone in the iungs the same changes as in the adult, but the 
reverse. Had it been in the septum auricularum, it must have 
mixed with the blood coming directly from the anterior cava, 
which would have rendered it less pure, and therefore could not 
have supplied the brain with blood sufficiently pure to perform its 
functions. This is obviated by its being just at the entrance of 
the auricle, so that but little of the blood goes into the right auricle. 
The use of the ductus arteriosus appears more simple. The whole 
of the blood in the right ventricle not being wanted for the sup- 
port of the lungs, part passes immediately into the posterior aorta, 
to be mixed with its blood, and thus assist in supporting the pos- 
terior parts of the body. These openings become obliterated by 
degrees after the foetus is born, the circulation being then very 
different. 
THE VETERINARIAN , SEPTEMBER 1, 1836. 
Ne quid falsi dicere audeat, ne quid veri non audeat. — Cicero. 
ON THE REPRODUCTION OF THE NERVES. 
[From Lund’s Physiologische Resultate der Vivisectionen neuerer Zeit.] 
The question, whether the nervous substance is really repro- 
duced, has for a considerable time occupied the attention of phy- 
siologists. Numerous experiments have been tried on the subject 
by the physiologists of the last century, but the question at the 
commencement of the present century remained unanswered ; 
and notwithstanding the united exertions of anatomists, physiolo- 
