120 rico leas 
biani in his infusions in Paris, was traced by Mr. Samuelson, first in moistened 
dust from the high road near Liverpool, then in dust taken from his own window 
and washed in distilled water, and lastly even in pure, boiled, distilled water, after 
it had been exposed a few days in the open air in Liverpool. The author watched 
and carefully described the development of this species (Cercomonas acuminata) 
from its first appearance to its full growth. 
PHYSIOLOGY. 
On the Function of the Auricular Appendix of the Heart. 
By Isaac Asun, A.B., MB. 
The author considered that the well-marked contrivance exhibited in the appen- 
dix, such as the presence of carnez columne in this portion only of the auricle, 
indicated that it subserved some function more important than that usually assigned 
to it, namely the better mixing up of the blood received from the veins. Three 
ascertained facts, none of them of much apparent value separately, would, when 
connected together, give a hint as to what that function might be. 
The first was that the auricle, though having walls much thinner and weaker 
than those of the ventricle, was yet able powerfully to distend the latter. 
The second fact was that the auricle, unlike the ventricle, did not completely 
empty itself of blood. 
he third fact was that the auricular appendix, though placed at a distance from 
the auriculo-ventricular orifice, yet was the last portion of the auricle to contract. 
From these three facts, taken together, Dr. Ashe inferred that the function of the 
appendix was to effect the complete distension of the ventricle, notwithstanding the 
powerful resistance of its thick muscular walls when distended nearly to their 
utmost. The force of the appendix would he transmitted to the ventricle by means 
of the small column of fluid still remaining in the auricle, and this force would be 
multiplied within the ventricle as many times as the superficies of the fluid within 
that chamber exceeded the surface which would be presented by the superficies of the 
fluid within the appendix. Against the walls of the auricular sinus this force would 
be @ minimum, in consequence of the small superficies of the fluid still remaining 
within it. 
To a certain extent the same thing would be effected by the contraction of the 
sinus alone, for its force would become multiplied within the ventricle in measure 
as the superficies of the fluid in the latter increased in proportion to that in the 
former, which diminished pari passu; but the force exerted by the sinus becomes 
diminished towards the close of its contraction, just when the maximum effort is 
required, and would even vanish altogether were it not for the small column of fluid 
remaining in the auricle. Dr. Ashe regarded the function of the carne column 
as being neither to increase nor to diminish the strength of the appendix, for either 
object could be attained with smooth walls—yet both views had been put forward 
—but as being to effect the complete emptying of the appendix, since the force of 
this organ could not be exerted on the ventricle except by the injection of a con- 
siderable quantity of fluid within it. Tor this contrivance Dr. Ashe suggested the 
name of “the hydrodynamic apparatus of the heart.’ 
Dr. Ashe also considered that this powerful distension of the walls of the ven- 
tricles might be an operating cause of their contraction, analogous to the view 
which had been suggested regarding the cause of the contraction of the walls of the 
uterus at the completion of the period of pregnancy. 
On the Function of the Oblique Muscles of the Eye. 
By Isaac Asun, A.B., M.B. 
The author doubted the view that assigned to these muscles the function of 
rotating the eyeball on its antero-posterior axis, never having observed such rota- 
tion either incidentally or in experiment. The vision might be directed to any 
object by the action of the recti alone. 
The view had been put forward that such rotation was necessary in order that 
