142 



OBSTETRICAL PHYSIOLOGY 



2 instances of 143 days 



15 



22 



30 



55 

 68 

 80 



144 



145 

 146 

 147 

 148 

 149 



57 instances of 150 days 



From this list we observe that the difference between the longest and 

 shortest period was only three days, by far the largest number of births 

 occurring between the 147th and i5is't days. The average duration of 

 pregnancy was about 149 days. Gestation was longer with the female 

 than the male lambs, and this Magne attempts to explain by the greater 

 development and weight of the former, which rendered parturition more 

 difficult and slow. 



Colin says the average period in the Sheep is 151 to 152 days, though 

 parturition may take place from the 145th to the i6oth day. 



Dieterichs gives the shortest period as 146 days, the longest 157 — 

 average, 151 days; and Baumeister and Rueff state the shortest period 

 in the Sheep and Goat as 135 days, the longest 160 — average, 144 days ; 

 the male lambs requiring, as usual, the longest period. With regard to 

 breed, these authorities found that the period of gestation in Merinos 

 averaged 150*3 days; while with Southdowns it was only i44"2 days, or 

 six days less. 



In the Merinos, for the male lamb the average period was i5i'i days, 

 female lamb i5o'6 days, and twins i49'9 days ; and in the Southdowns, 

 for the male lamb 1447 ^^^.ys, female lamb 144*1, and twins 144 days. 



Magne asserts that the Goat goes a little longer than the Sheep — the 

 average being five months and some days. 



Pig. 



The Pig is usually pregnant/^/zr fnonths, or according to some author- 

 ities three months, three weeks, and three days. Baumeister and Rueff give 

 the longest period as 130 days, the shortest no — average, 120; while 

 Dieterichs gives 109 days as the shortest and 133 as the longest — average, 

 115 to 116 days ; and Magne says that it is rarely less than 109 or more 

 than 120 days. Rainard noted the period of gestation in 65 Pigs, and 

 reports it to be as follows : — 



2 instances 104 days. 

 10 " no to 115 days. 



23 " 116 to 120 days. 



27 " 121 to 125 days. 

 2 " 126 days. 

 I " 127 days. 



The average was, therefore, 119 days, the interval between the longest 

 and shortest periods being 23 days. 



Bitch. 



The Bitch goes with young about two months, or from 58 to 65 days ; 

 the average being (>t^ days or nine weeks. Baumeister and Rueff state 

 the shortest period to be 55 days, and the longest 70 — the average being 

 60 days. 



