908 
diameter to the other was first pointed out by 
Professor Naegelé, of Heidelberg, and must 
be looked upon as a fact of great importance in 
the mechanism of parturition, second only to 
the discovery of the oblique position of the 
head by Solayres de Renhac and Matthias 
Saxtorph in 1771. Sometimes the head does 
not make the change above mentioned, but 
comes out with the forehead more or less for- 
wards, the swelling of the cranial integuments 
being situated on the right or left frontal bone. 
The face, like the head, may present in two 
ways, either with the right or the left side fore- 
most. As in the head presentations the sagittal 
suture crosses the os uteri, so in the present 
instance is this the case with the ridge of the 
nose. 
In that position which is of most frequent 
occurrence the chin is turned to the right side 
of the pelvis, the right eye and zygoma being 
lowest and in the middle of the pelvis ; this, 
therefore, shows that the face, like the head, 
comes obliquely not only as to the transverse 
diameter of the pelvis, but also as to the axis 
of its brim. The ridge of the nose is not only 
the part of the face which we first are able to 
distinguish when the os uteri is but slightly di- 
lated, but from its conducting the finger in one 
direction to the soft cushiony end of the nose, 
and in the other to the broad hard expanse of 
the forehead, it furnishes us with an excellent 
means of ascertaining not only that the face 
presents, but in what position. 
As the os uteri dilates and the face advances, 
the chin turns towards the right foramen ovale, 
so that by the time it has entered the vagina, it 
is no longer the right eye and zygoma which 
form the presenting part, but the right cheek, 
this being now the part which the finger first 
touches upon during examination, precisely as 
in the first position of the head, it is the su- 
aioe and posterior quarter of the right parietal 
ne; so, in like manner, it is this part of the 
face upon which the bruise-like swelling is 
situated, which it brings with it into the world. 
It would seem that there is a considerable ana- 
logy between the first position of the head and 
that of the face, and that the one can probably 
pass into the other ; in both the right side pre- 
sents, and if the head in this position swings 
round upon its transverse diameter, it becomes 
the first position of the face. 
The other or second position of the face is 
merely the reverse of the first. The left eye 
and zygoma present at the beginning of labour ; 
and as the chin, which is turned more or less 
to the left, moves somewhat forwards, it be- 
comes the left cheek which first passes through 
the os externum, and upon which the swelling 
of the face is situated. 
According to the best averages, we may state 
that face presentations occur about once in 290 
Jabours, and from the observations of Professor 
Naegelé, jun., the proportion of the second po- 
sition to the first is as 1.29 to 1. Beyond 
being now and then a little more tedious, la- 
bours where the face presents are not more un- 
favourable for the mother than where the head 
presents ; for the child, however, they are not 
PARTURITION. 
so favourable; the re upon the neck 
duces considerable baer crore which 
now and then proves fatal. : 
The lower part or pelvic extremity of the 
trunk may present with the nates, eg B= a 
the feet; but as the former are by far the most 
bulky, we may bring them under the general 
head of nates presentations. In this case the 
child may present with the back or abdomen 
forwards, in either of which the transverse dia- 
meter of its pelvis rans obliquely, that ischium, 
which is turned forwards, being lowest in the 
pelvis. The position with the back of the child 
more or less forwards is the most common, 
being in the proportion of 3 to 1 of the other — 
position. The presenting ischium advances — 
through the os externum; the abdomen “and — 
chest follow ; and the arms, which are crossed 
upon the breast, are usually born at the same 
moment. The shoulders follow in the same — 
direction, that shoulder being first expelled — 
which is turned more or less forwards. The — 
head, with the chin pressed upon the breast, — 
enters the pelvis in the opposite oblique dia- 
meter to what the shoulders did; and while 
the occiput rests against the symphysis pubis, 
the chin, followed by the rest of the face and — 
forehead, sweep over the perineum as the head 
turns upon its transverse diameter from below 
upwards. Sometimes, although rarely, the 
chin is not depressed upon the breast, but the 
head enters the pelvis in a contrary direction, 
viz. with the occiput pressed into the nape ¢ 
the neck, the face turned upwards, and is bor 
in this position. Where the abdomen of thi 
child is turned forwards, it almost invarial 
turns more or less backwards during the pro 
gress of the labour, either shortly after the 
nates are expelled, or as the thorax is advanei 
through the pelvic outlet. . 
In all these presentations, the process of I; 
bour appears to resemble, as far as possibl 
that in the lower classes of animals. ‘The fi 
stage is employed in attaining two importan 
objects ; firstly, in giving the child a natu 
position, viz. with its long axis parallel 1 
that of the passage through which it has to co 
and in so dilating the os uteri that the whole 
it shall disappear, the uterus and vagina formi 
one continuous canal, exactly resembling, as 
as the mechanism of the expulsion is concern 
the same process in the lower animals. 
As far as we know, it is only in the hun 
subject where it is possible for the foetus 
present across, or where its long axis does: 
correspond with that of the passage ; in this¢ 
it presents with the arm or shoulder, and ¢ 
not be born in this position. This unnat 
presentation chiefly arises from the contract 
of the uterus in the first stage being more or 
perverted or obstructed by certain causes; t 
if the uterus be much distended with lit 
amnii, the slight Parente contractions ai 
commencement of labour will have little ort 
effect in keeping the fetus with its long @ 
parallel with that of the uterus, for the sides” 
the uterus are now too far separated to act @ 
it, and as the uterus from its distention 
proaches to the globular form, the child will 
