66 OBSTETRICAL PHYSIOLOGY. 



It may likewise be due, though temporarily, to premature or tardy 

 coition when the generative organs are not in a physiological condition 

 for conception, or when they are in an irritable, abnormal state. Under- 

 fed or over-fed animals generally do not breed so readily as those which 

 are in moderate condition ; fat animals are especially unfruitful. 

 Excitable, vicious Mares are less likely to procreate than those w^hich 

 are of an equable and gentle disposition. The latter are often impreg- 

 nated at one attempt ; and it has been observed that with Mares 

 accustomed to work, active exertion, even to produce fatigue, before 

 being put to the horse, is favourable to conception. So it is that the 

 Arab submits his Mare to a severe gallop, and brings her almost breath- 

 less before the Stallion, when, the act being accomplished, he leaves her 

 quietly at rest for some hours. 



Various diseased conditions of the generative or other organs, as well 

 as general derangements, may also prove antagonistic to fecundity. 

 There may be disease or alterations in the ovaries. Fallopian tubes, 

 uterus, or vagina, which will hinder conception ; and if any material 

 obstacle to the contact of the spermatic fluid with the ovum be present in 

 these parts, fecundation cannot take place. Tumours of various kinds in 

 this region are not an infrequent cause of sterility. 



Eueff and others have observed an imperforate, dense, and tough 

 hymen to be a cause of infecundity in the Mare. 



The fault may rest with the male, and be due to imperfection in his 

 generative organs, the absence of spermatozoa in the seminal fluid, or 

 general or sexual debility of a temporary or permanent character. Or 

 the spermatozoa, when introduced into the genital canal, may have 

 their vitality destroyed by the secretions they meet with ; or the im- 

 pregnated ovum may be unable to fix itself on the mucous membrane 

 of the uterus because of disease existing there, such as endometritis. 



In all these conditions a careful examination should be made, as 

 removal of the obstacle to generation may, in many instances, be quite 

 within the scope of surgical or medical measures. More particularly is 

 this the case when the obstacle is related to some abnormal condition 

 of the cervix uteri — a circumstance more common than is generally 

 supposed. 



Occlusion of the canal leading to the cavity of the uterus — the os — 

 has been known as a cause of sterilitj^ in the Mare and Cow from the 

 earliest times. This occlusion may be complete during coition, and 

 prove fatal to conception ; or it may be due merely to a spasmodic con- 

 dition of the muscles of the cervix. The oiled hand should be intro- 

 duced into the vagina to ascertain the state of the part ; when, if the 

 closure is suspected to be owing to muscular defect, the cervix may be 

 smeared with extract of belladonna. If, however, this does not succeed, 

 or if there be hypertrophy, disorganization, or rigidity, then an opera- 

 tion will be necessarj'. Hypertrophy from plastic exudation and the 

 formation of false membranes, is a frequent cause of sterility, and usually 

 occurs during or after the first birth, particularly in the Cow. In many 

 cases the morbid closure of the os can be remedied in a very safe and 

 simple manner. The animal is secured — if a mare by the " side-line," 

 if a Cow by fastening the two hind-legs together, though not too close 

 — and the oiled hand, in the form of a cone, passed up the vagina to 

 the cervix in a half-rotary or screwing manner ; on reaching this, the 

 tips of the fingers are to be gently insinuated by the same movement 

 into the os, and pushed on until the cavity of the uterus is reached. A 



