200 Journal of Travel and Natural History 



something else than the blood of mammals. The entomologist occasionally, 

 even in this country, finds specimens in the fields, and in the south of Europe 

 we have heard of their occurring in excessive numbers in sandy places where 

 travellers have encamped. In these cases no doubt it may be said that the 

 visitors have chanced to pitch upon a spot where gypsies, vagrants, or dogs, 

 plentifully stocked with the vermin, had been previously reposing, and that it 

 was merely the surplusage that remained after their departure that had come 

 under their observation. But the following instance told to us by a friend as 

 having fallen under his own observation in Brazil cannot be so accounted for. 

 A small isolated house or cottage stood on his property at some little distance 

 from any other house. It had remained unoccupied and locked up for two 

 years. At the end of that time a tenant offered and the proprietor and his 

 overseer went to look over the house preparatory to letting it. They unlocked 

 the door and opened the windows, and by the time they had done so when they 

 happened to cast their eyes down they saw to their surprise a remarkable change 

 on the colour of their garments. They had come in with white trousers but 

 now up to the knees they were if not black at least more black than white : they 

 were a moving mass of fleas peppered all over them and advancing rapidly above 

 the knees. It is unnecessary to say that their retreat was rapid. It may be 

 thought that another necessary coroUaiy to the story would be that they 

 lost their tenant, but they did'nt. There is a plant or flower in Brazil to 

 which (as to the Pyrethrum in Europe and Asia) fleas have a personal 

 antipathy, and wherever it is scattered, either in powder or fresh, they take 

 themselves off. With this, and white lime, and soap and water, and per- 

 haps a little personal indifference, the tenant got the better of the fleas ; 

 but the question is, how they had subsisted and multiplied to such an extent 

 during the two years in which the house had been locked up. During the 

 portion of that time, indeed, which the most if not all of that immense 

 population must have passed in the larva state, there is not the same difficulty ; 

 for it is known that in that state they live on animal debris, of various kinds, 

 such as fur, feathers, wool, &c. , but from the time that they are provided with 

 a sucking apparatus, they must have had something to suck the blood out of, 

 or else have "gone without." The same problem applies to mosquitoes, gnats, 

 and other blood-suckers. It is plain that in many of the districts where they 

 abound, and where man or beast can scarcely live, the vast majority must pass 

 and end their lives without ever having the opportunity of putting their sucking 

 apparatus into operation. With the mosquitoes, it may be that like the 

 ephemera, their life in the perfect state is bounded by a day. But it is not so 

 with fleas. Many facts regarding them prove that they see many days. What 

 then do they live upon? 



