CHAPTER VI 



THE cases described hitherto show that small groups of 

 abnormal animals or sports occur in nature. Although 

 the members of a group are few as a rule, the groups are 

 many. This important fact is likely to be overlooked, 

 unless one realizes the smallness of our observations in 

 proportion to the immensity of the thing to be observed. 

 We must imagine the frequency of these groups in rela- 

 tion to the mass of rodents in India as a whole. The 

 portion of the mass examined is very small, but a con- 

 siderable number of such groups were found in it. We 

 may, therefore, be sure that although family groups are 

 small in membership and usually temporary in duration, 

 yet they are of frequent occurrence. 



The ideal method of research would have been to have 

 determined the number of abnormal family groups per 

 million of the rodent population. This, however, was 

 not possible ; records such as were kept at Poona were 

 exceptional. But it is probable that the number of groups 

 per million would be not less than ten, and we must 

 multiply the number by a thousand if we wish to esti- 

 mate the number of such groups in India at the moment 

 and by a much larger number to find how many have 

 been in existence, on and off, during the last century. 



But we do not know the actual frequency of these 

 family groups, and it would hardly be possible to estimate 



