146 BRITISIL SERPENTS. 
mate. It is manifestly impossible to reconcile such 
varying statements as these, unless one lumped them 
all together and said that the adder family varies in 
number from 5 to 40, which would be very apt to 
convey the impression that very httle was known 
about it. An author can only give his own opinion 
and the reasons for arriving at it, which latter point 18 
too frequently omitted. People often say that they 
once killed an adder which had its young ones play- 
ing about it, the young numbering about such and 
such a figure. These figures are of necessity a very 
hasty estimate on the part of the observer, made, 
moreover, at a very exciting moment. It is not an 
easy matter to count a number of young adders 
seuttling away and at the same time keep a careful 
eye ou the mother; and very little reliance is to be 
placed on this kind of haphazard evidence. There is 
ouly one reliable method of observation applieable to 
adders in a state of nature, and that is the dissection of 
a sufficiently large series of gravid female adders shortly 
before the time of parturition This condition of the 
female may be found, as has been said, in the month 
of August. At this time the embryo adders are well 
on in development, and ean be handled and counted 
with ease and accuracy. They are several inches long, 
according to the stage of development, and every 
embryo that is to be born can be taken out of the eee 
50) 
''This is also the method adopted to determine the relative pro- 
portion of the sexes, 
