78 THE GROWTH OF GROUPS 



that the writer found these unusually light-bellied animals 

 distinguishable from the others as a class. It was 

 unnecessary for the purposes of plague investigation to 

 take into account the varieties of Mus rattus, conse- 

 quently the proportionate numbers of the unusually 

 light -bellied ones to the common kind was not recorded. 

 During my visit to Bombay I was able to satisfy myself that 

 those spoken of as " unusually light bellied " were white 

 bellied when cleaned, and that they comprised less than 

 one per cent, of the rodent population. The number of 

 rats which were being caught at the time was about five 

 hundred daily. Although some days might pass without 

 the capture of a single white-bellied rat, whenever animals 

 of this kind were obtained they were brought in, two or 

 three at a time from one and the same house. This 

 peculiarity in their occurrence was noticed again and again, 

 in various parts of India. 



Now let us see what the Commission found in the 

 Punjaub. I have already mentioned the experience of 

 Captain Davys in the Amritzar district, his observations 

 were made independently of the Commission, at a later 

 date. The Commission selected two villages, named 

 Dhand and Kassel, for their investigations. During a 

 year they obtained 7525 rats which are described as 

 follows : " The rats taken in the Punjaub villages were 

 all of one species named Mus rattus . . . the colour 

 of the dorsal fur is usually brown, while the belly is 

 greyish, dirty yellow, or occasionally quite white." Here 

 also is clearly expressed the opinion that the white- 

 bellied ones are a recognizable class distinct from the 

 common ones. In Bombay some of the rats were described 

 as unusually light bellied, while in the Punjaub they are 



