794 Diseases of the Genital Organs 



gravid uterus of the cow. There is one fundamental differ- 

 ence in the placental arrangement which changes materially 

 the method of invasion. The utero-chorionic space of the 

 cow facilitates the rapid dissemination of infection through- 

 out the entire cavity without necessarily involving seriously 

 the placental structures (cotyledons). In the mare there is 

 no utero-chorionic space, but the endometrium everywhere 

 participates in the placental functions, so that the endome- 

 trium and chorion are everywhere in intimate placental 

 contact. Any advancement of infection along a given path 

 therefore necessarily destroys the placental relation between 

 chorion and uterus. The chief habitat of infections within 

 the gravid uterus of the mare, as revealed by clinical study, 

 is the same as in the cow. The most destructive location of 

 infection is at the cervical end of the uterus, from which 

 point of vantage it causes abortion. Clinical experience 

 clearly teaches that the second bacterial rendezvous is the 

 apex of the non-gravid horn where it may develop a local- 

 ized apical endometritis, revealed at the termination of preg- 

 nancy by retention of the chorion in the non-gravid horn, 

 while the remainder of the membranes detach promptly and 

 their weight causes a rupture across the base of the non- 

 gravid portion, the major portion of the membranes falling 

 away while the diseased non-gravid branch remains. If 

 one has the opportunity to make a clinical examination of a 

 mare nearing abortion, there is frequently, perhaps always, 

 an absence or destruction of the uterine seal, the cervical 

 canal is open and suppurating, and the chorion is detached 

 from the uterus over a varying area at the cervical end. 

 This is well illustrated in Fig. 230. The parturient rupture 

 (1) is slightly at one side of the central axis because there 

 exists a central hard, somewhat desiccated necrotic area (2) 

 which possesses greater resistance than the contiguous area. 

 The photograph reveals at 3 the radiation of the infection 

 from 2 toward the ovary. In some cases, if not in many. 

 the veterinarian making an examination at an opportune 

 time, is able to palpate clearly the necrotic, parchment-like 

 area of the chorion, and through it to palpate a living fetus 



