PROFESSOR SIMONDS’S LECTURE. 
517 
in purity ; consequently, in the young of animals there are vessels 
for the equal distribution of the blood, which are not met with 
in adults. The period of utero-gestation, or length of time that 
the foetus is detained in the uterus, depended upon a variety 
of causes, and differed in nearly every animal. The mare carries 
her young 48 weeks, the cow 40, the sheep 22, the bitch 9, and 
the pig 16 weeks. Was it not astonishing that impregnation 
should take place and the foetus be perfected in the short space of 
nine weeks 1 If, however, they descended the scale and looked to 
other animals, they would find that its development would be 
effected much earlier. When the foetus was fully devoloped, it 
was expelled from the womb, or, in other words, labour took place. 
Now, unless the uterus possessed capabilities for throwing off its 
burden, neither birth nor abortion could occur. But labour did not 
entirely depend upon the full development of the foetus, nor upon 
the capability of the foetus to live independent of the mother. 
Every one would be acquainted with the fact that impregnation 
was a mysterious effect taking place from certain causes, and 
ending in the birth of the young. The fitness for impregnation 
was always associated with a train of appearances or symptoms 
which denoted the condition of the animal at that particular period. 
When parturition was about to commence, the animal became 
restless, and separated herself from the herd : she lay down, and 
rose frequently. These and other symptoms are associated with in- 
termissions of pain, which are called propulsive or " bearing down,” 
continuing with more or less force fora certain length of time. The 
time that the pain continues would depend upon a variety of 
causes. First, upon the freedom with which the mouth of the womb 
dilated itself : for during the whole period of utero-gestation the 
young animal was, as it were, enclosed in a box, which had to be 
opened before it could escape. The dilatation of the mouth of the 
womb was always associated with pain ; and here he would remind 
all proprietors of stock not to be in too great a hurry with their 
animals at the time of parturition, although they may express great 
uneasiness. He had known many cases where valuable animals 
had been lost in consequence of the impatience on the part of 
the owners in seeking too soon to give their assistance to the 
mother. He had also known cases where the symptoms of 
approaching parturition had passed off, and not returned for two or 
three days ; for it did not follow that, when the mouth of the womb 
was opened — when every thing was prepared for the expulsion of 
the young — that the foetus should immediately pass through. 
Therefore, he would again say, do not be in too great a hurry, 
especially with ewes; for very frequently labour was extremely 
languid. Timely assistance must, nevertheless, be afforded. 
VOL. XXL 4 A 
