ABNORMALITIES IN THE PAHTURIENT PASSAGRS 177 



sion, is of disadvantage in such cases. A very simple and 

 effective means consists of placing a pillow filled with warm 

 hayseed upon the'lumbar region. 



PARTIAL OR COMPLETE OBLITERATION OP THE CERVICAL CANAL. 



By it is understood a partial or complete, closure of the 

 cervical canal or part of it, so that during birth no dilatation 

 of the cervix uteri occurs. 



The causes of this atresia of the os uteri, as it is termed at 

 times, may be : Retraction from cicatricial tissue following 

 injuries. When in previous pregnancies labor was difficult and 

 an extraction resulted in severe injuries to the cervical wall, a 

 great deal of granulation tissue may follow, contracting Liter 

 and forming scar-tissue. It happens that excessive traction 

 during insufficient dilatation is followed by rupture of the os. 

 During recovery the cervix is slow to close, so that conception 

 may take place before the parts are healed. A cervix destroyed 

 in this manner regenerates by young connective tissue, which, 

 contracting later, seriously inteiferes with dilatation of the 

 cervix at parturition. 



Cartilaginous degeneration mainly due to a deposition of 

 calcium salts, is occasion allj-, but, happily, seldom, observed. 

 In this condition dilatation of the os uteri is impossible. 



Certain anomalies occurring during foetal development 

 (due to an insufficient union of Miiller's ducts), resembling 

 fleshy bands, may be found lying in front of the os uteri. 



Adhesions between the walls of the cervical canal have 

 been observed (Goring). 



Tumors of various dimensions now and then cause obliter- 

 ation of the cervix uteri, as fibromata, leiomyomata and carcin- 

 omata (Lucet, Wilhelm). 



Symptoms. — In such animals everything is prepared for 

 parturition. It sometimes happens, when the broad uterine 

 ligaments and perineal fascia are relaxed, that in consequence 

 of the violent pains, assisted by the abdominal muscles, the 

 upper wall of the vagina and the closed os are pushed back- 

 ward until they appear between the labise of the vulva. Vag- 



