458 BOVINE PATHOLOGY. 



10. Twin calves J united more or less intimately. 



11. Folymelians, many-limbed forms. 



We have mentioned some of the above forms more on 

 account of their curious characters than of their practical 

 importance in parturition. These peculiar creatures used 

 to be termed Lusus Naturce, but recently the study of 

 them. Teratology, has been remarkably advanced by the 

 experimental method, and it has been shown that they 

 are not '^ freaks/' but produced according to definite 

 laws. Thus they may depend upon pressure as preventing 

 the development of any part, upon amputation performed 

 by a twist of the umbilical cord, upon budding of the 

 ovum, or upon exaggerated or arrested development. The 

 various kinds which occur in domesticated animals are 

 treated of at length by Fleming in his ' Obstetrics,^ where 

 he fills a great blank which long existed in English 

 veterinary literature. Monstrosities are of very frequent 

 occurrence in the cow, and cases of double or even triple 

 calf, twisted spine, dicephalus, and polymelianism may 

 give rise to difficult parturition and necessitate adjustment, 

 and often embryotomy. Some monsters are unable to live 

 independently of the parent, others are unable to stand 

 the pressure exerted upon them in expulsion, as those with 

 ectopia cordis. Many live and are much appreciated by 

 itinerant showmen. Sometimes it is most astonishing 

 what peculiar bodies can be expelled without much 

 trouble. 



Whenever the foetus cannot be removed by ordinary 

 traction, embryotomy must be tried. It consists in the 

 reduction of the size of the foetus by removal of parts, which 

 are separated with a special concealed knife (Fig. 103), or 

 by means of a curved pointed blade which has a ring for its 

 handle (Fig. 105), and thus may be fixed on the middle 

 finger and carried in the hollow of the hand into the uterus. 

 Operations with these knives are limited by the small 

 space in the pregnant uterus, and by the cramped state of 

 the arms of the operator from the pressure exerted upon 

 them, particularly during the uterine throes. Sometimes 

 the chain saw (Fig. 106), will be found useful. The fore 



