726 
ON THE GESTATION OF COWS. 
the 313th day. How closely does this approximate to the ac- 
count given by Earl Spencer! He adds, that the period of 
gestation is longer in the larger German cattle than in the 
smaller breeds. It would be an interesting inquiry whether 
this were the case with regard to our cows. Who will give us 
the usual period of utero-gestation in our smaller Scotch and 
Welsh cattle, compared with our larger breeds on the fertile 
pasturage of the south 1 
It would seem that one reason which prompted the noble 
lord to this inquiry was the error committed by the author of 
the work on “ Cattle,” who assigned 270 days as the usual pe- 
riod of pregnancy. He did so. Will the reader, however, who 
may happen to be in possession of that work, turn to page 5271 
The author has no sooner assigned the usual period of pregnancy 
than he refers to one of the latest reports of M. Tessier, in which 
he had recorded the period of utero-gestation in 1131 cows, as a 
corroboration of his statement. In these 1131 cows, M. Tessier 
says that the shortest period of pregnancy was 240 days, and 
the longest 321. Now what had the author of the work on 
Cattle done 1 He had added together the extreme numbers, and 
he had divided the sum by 2, in order to obtain the average. 
It was a rude method, but the only one that he could pursue. 
He had not the valuable table of Earl Spencer. Two hundred 
and forty added to 321 make 561, and this divided by 2 gives 
a quotient of 280, or, more accurately, two hundred and eighty 
and a half - — he pledges himself as to the accuracy of this state- 
ment — and then, in the hurry of writing, or from some unac- 
countable etourdissement of the moment, he sets down 270 in- 
stead of 280, and this was not afterwards corrected or observed. 
It was a shameful piece of carelessness, and he deserves the 
gentle castigation which he has received from the noble earl, 
and the harder slap from the author of “ another work.” He 
confesses, however, that he is not altogether sorry for it ; for it 
has elicited this “ table ” from the noble lord, and we have no 
longer the strangely indefinite period of “ between nine and ten 
months,” nor the somewhat too early one of 280 or 281 days ; 
but the interval between that and the 290th day in five cases 
out of seven, or about the 284th or 285th day — 314 Durham 
cows out of 764 having calved before the 284th day, 310 after 
the 285th, and no fewer than 140 on those very days. — Y.] 
