EBB AND FLOW OF ANIMAL LIFE 111 



ing the Mice and Lemmings, I have not complete 

 data, but they are believed to multiply and suffer in 

 the same way. 



Third. The purely carnivorous, whose existence 

 is dependent on the Rabbits. This includes chiefly 

 the Lynx and Fox, but in less degree all the small 

 carnivores. 



In some cases such as the Marten, over-feeding seems 

 as inimical to multiplication as under-feeding, and it 

 will be seen that each year of great increase for this 

 species coincided with a medium year for Rabbits. 



But the fundamental and phenomenal case is that 

 of the Rabbits themselves. And in solving this we 

 are confronted by the generally attested facts that 

 when on the increase they have two or three broods 

 each season and 8 to 10 in a brood; when they are 

 decreasing they have but one brood and only 2 or 3 

 in that. This points to some obscure agency at work; 

 whether it refers simply to the physical vigour of the 

 fact, or to some uncomprehended magnetic or helio- 

 logical cycle, is utterly unknown. 



The practical consideration for the collecting natural- 

 ist is this: Beaver, Muskrat, Otter, Fisher, Raccoon, 

 Badger, Wolverine, Wolf, Marten, Fox reached the 

 low ebb in 1904-5. All are on the up-grade; pre- 

 sumably the same applies to the small rodents. Their 

 decacycle will be complete in 1914-15, so that 1910-11 

 should be the years selected by the next collecting 

 naturalist who would visit the north. 



For those who will enter before that there is a rea- 

 sonable prospect of all these species in fair numbers, 



