PARTURIENT PARESIS. 
397 
supervene, the physiological contraction of the uterus, which as is well 
known are dependent upon the vigor of the animal and other conditions, 
and may therefore be more or less powerful. The capillary network 
shrinks with the maternal placenta and the womb can consequently not 
take up th« same quantity of blood as during the time of advanced preg¬ 
nancy. 
If now there was no other place for this excess of blood from the 
uterus, then the arterial blood pressure would become notably stronger 
immediately after birth, and according to Franck’s hypothesis this 
would especially be seen in those cases where the uterine contractions 
are very vigorous. 
But already some time prior to birth, in the last period of pregnancy, 
there occurs a gradually increasing swelling of the udder and thereby 
an increased flow of blood to it. This is in consequence of increased 
functional activity in the organ. After parturition, the increased vas¬ 
cularity of the gland is further stimulated by the sucking of the calf 
and by milking, consequently mechanical causes also exert an influence 
upon the vascular activity and contribute to the increase of the milk se¬ 
cretion. This begins, it is true, almost always prior to parturition, but 
only to a small degree in comparison with the secretion after calving ; 
for after parturition there can be more milk withdrawn several times 
daily than the quantity which the mammae have secreted in several days 
before birth. 
It is therefore ver}’- doubtful if the augmented blood supply required 
by the udder after birth, is materially less than that quantity of blood 
which the uterus demanded during the later stages of pregnancy. A 
direct measure and a direct comparison are not readily attainable ; for 
this purpose one needs know the volume of the blood stream which goes 
to the uterus and to the udder before and after parturition ; but indi¬ 
rectly we may arrive at a trustworthy conclusion, since the nutrition of 
the foetus and the secretion of milk each draws its material from the 
blood, in turn the blood secures its nutritive elements from the ali¬ 
mentary tract—that is, from the ingested food. 
As the nutrition of the foetus and the production of milk each draws 
its nutriment from the blood, so the blood in turn secures its nutritive 
elements from the digestive organs, or rather from the food elements in¬ 
gested by the mother. The nutritive elements in the food give, there¬ 
fore, a standard of measurement of what can be drawn from the blood, 
as well in pregnancy as during lactation. 
If now we inquire, if the pregnant cow requires more or less food 
than the fresh milk cow, which under our present state of development 
must produce economically a sufiicient quantity of milk, each agricul¬ 
turist can say to us that the former requires less. 
