198 GENERATION 



In the uterus of a sow sixteen days gone, the foetus was formed, and 

 its purse-shaped membrane [chorion and allantois] was above a foot 

 long in some. This membrane, with the foetus nearly in the middle 

 between each end, occupied nearly the whole length of the cavity of the 

 uterus, like a tape-worm in the intestines. Through the whole course 

 of the uterus was a white mucus almost like cream ; and where the 

 foetus lay, this was most in quantity 1 . 



In two other sows that were only allowed to go ten days, I could not 

 observe any change whatever, and there was none of the mucus to be 

 found in either uterus. 



The connexion between the outer covering of a [foetal] pig and the 

 uterus appears to be only one of contact ; for they separate with as much 

 ease as any two wet substances can do that have no connexion but 

 that of having lain together. Upon close examination, there appears not 

 to be the least violence committed upon separation. The inside of the 

 uterus is thrown into circular rugae, and so is the external surface of 

 the outer membrane of the foetus, which appears to confine the mem- 

 branes in their situation. 



There are on the outer surface of the external membrane of the foetus 

 a vast number of small circular spots, which are rather whiter or paler 

 (from being thicker) than the parts of the same membrane, with a 

 darker centre. These spots do not appear to be more vascular upon in- 

 jecting, than any other part of the same membrane 2 . 



In the year 1777 I spayed a young sow of one ovarium only. When 

 she was of age, I gave her the boar, and she brought forth six pigs. 

 The second time she had eight (I slit her ear to know her) ; the third 

 litter was only six ; the fourth litter of ten ; the fifth litter, March 

 1782, she had ten ; the sixth litter, September 1782, she had nine pigs. 

 In this instance she had been served with the wild boar ; five of the 

 nine were like the father, three like the mother, and one like neither. 



The sister of the above sow, although not spayed, did not take the boar 

 so early as the spayed one did. When she did so, I only allowed the 

 boar to serve her once (as was also the case with her spayed sister). 

 This was with a view to see if once was sufficient to impregnate several 



and its contents only observed, which might have been the ' serum ' that Hunter 

 mentions. Had the exterior covering of the mam miliary eminence been carefully 

 scratched open, the ovarian ovmn might have been detected and removed entire.] 



1 [Hunt. Preps. Nos. 3538-3541.] 



2 [When the veins and arteries are injected with distinct colours, the venous 

 capillaries form plexules in the centre of each of the circular spots. See the Prep. 

 No. 3541 A, presented by Professor Eschricht, of Copenhagen, the discoverer of this 

 arrangement.] 



