FERTILITY 651 



said to be from one in five to one in ten. 1 According to the records 

 of Franz 2 for the maternity hospital at Halle, the percentage of 

 cases in which abortion occurred was 15 '4. Williams 3 expresses 

 the opinion that in ordinary private practice every fifth or sixth 

 pregnancy usually ends in abortion, and that the percentage would 

 be considerably increased if one reckoned the early cases in which 

 there is a profuse loss of blood following a retardation of the 

 menstrual period, the actual fact of abortion being often obscured. 



Excepting in the case of sheep, there are no satisfactory data on 

 which to estimate the frequency of abortion among the different 

 kinds of domestic animals, but there can be no doubt that it is of 

 common occurrence, and that it occasions much loss to breeders. 

 For various varieties of English sheep Heape 4 found that the 

 percentage of abortion experienced by 300 flockmasters varied 

 from nothing to 23'75, while the percentage for 85,878 ewes was 

 2'39. The statistics showed that Dorset Horn and Lincoln breeds 

 suffered most from abortion, the losses from this cause being 



O 



respectively 4'11 per cent, and four per cent. The Southdown 

 breed were found to occupy an intermediate position (the percentage 

 of abortion being 2'86 per cent.), while the other breeds investi- 

 gated showed a smaller percentage of abortion. Among Scottish 

 breeds the percentage of aborting ewes does not generally exceed 

 two per cent., as far as could be ascertained ; but with Blackfaced 

 ewes it may be as much as five, or even a considerably higher 

 number, as a consequence of any special adverse circumstance. 5 

 It is possible, however, that the percentages of abortion are actually 

 somewhat higher than they appear, since its occurrence during the 

 early stages of pregnancy is not readily detected, and consequently 

 some of the ewes which were entered in the statistical returns as 

 barren may in reality have aborted. 



Among cattle in Great Britain the frequency of abortion, 

 according to Heape, 6 is not less than ten per cent, of the total 

 number of animals selected for breeding, and there can be no doubt 

 that in certain districts it is often very much higher, especially 

 where contagious or epidemic abortion occurs. Heape states further 

 that from ten to twelve per cent, of abortion is not unusual in herds 

 in which no contagious abortion is proved to exist. 



There are no data available on which to compute the frequency 



1 Kelly, loc. cit. 



2 Franz, "Zur Lehre des Aborts," Hegar's Beitrage, vol. L, 1898. 



3 Williams, Obstetrics, London, 1904. 



4 Heape, " Abortion, Barrenness, and Fertility in Sheep," Jour. Royal Agric. 

 Soc., vol. x., 1899. 



5 Marshall, " Fertility in Scottish Sheep," Trans. Highland and Agric. Soc., 

 vol. xx., 1908. 



6 Heape, The Breeding Industry, Cambridge, 1906. 



