656 THE POPULAR SCIENCE MONTHLY. 



With regard to Tasmania, it may also be observed that the native 

 inhabitants are universally of one color absolutely black which 

 w x ould suggest a previous history of malarial disease to which a pro- 

 longed succession of generations has finally secured complete adapta- 

 tion and consequent exemption from symptoms. How far the euca- 

 lyptus-tree, which here abounds, Las been instrumental in correcting 

 malarial disease, also deserves consideration. Possibly the sticky, pen- 

 dent leaves, and camphoraceous odor of the plant are not conducive 

 to the prosperity of the mosquito genus. 



The Dismal Swamp, so far from being exempt from mosquitoes, 

 is said to abound with them during the autumn. Alexander Hunter, 

 writing in "Potter's American Monthly," July, 1881, page 15, says : 

 " The mosquitoes were in uncounted millions ; they came armies on 

 armies, waves upon waves, clouds upon clouds, and charged in pla- 

 toons and single file, and threw themselves with bloodthirsty voracity 

 upon every living thing in reach." On the same page, however, his 

 negro guide, "Bob," is made to say that he reckons he would be 

 quite fat "but for the 'skeeters and chills." Another writer ("Har- 

 per's Magazine," vol. xiii, 1856, page 450) refers to an hotel having 

 been erected for a summer resort in the " Dismals," but " before the 

 month of August visitors, servants, and proprietors had all cleared 

 out and left the place in full possession of the mosquitoes and yellow 

 flies. These insects are said to be savage enough to worry the life 

 out of a mule. . . . The hotel was taken down." 



In so far, therefore, as regards the geographical relation between 

 mosquitoes and malarial disease, it may be said : 1. The two often 

 coexist ; 2. There is no decided proof that localities alleged to be 

 exempt from ague are also exempt from mosquitoes ; 3. There is no 

 locality noted for malarial disease where mosquitoes or other blood- 

 sucking insects do not exist. 



In those isolated cases of ague occurring during the winter or 

 early spring, before inoculating insects have made their appearance, 

 there may of course be other modes of inoculation. We have only 

 to admit the production of the bacillus malarice, its transmission in 

 the air and its deposit upon the skin, to see how easily it may be in- 

 oculated into the body by accidental wounds, such as pin-scratches, 

 the cut from a pocket-knife, or of a razor in shaving, etc. Further- 

 more, it is generally admitted by medical authorities that the period 

 of inoculation after the poison is introduced into the system may, 

 exceptionally, extend weeks and even months before symptoms are 

 developed. In these, or in some other ways, the isolated winter cases 

 referred to may therefore be explained without necessarily conflicting 

 with the mosquito theory. Finally, it seems incredible that a func- 

 tion so necessary to life as respiration a function that can not be 

 suspended in any atmosphere should be the means of infecting the 

 body with a fatal disease. It was surely never designed that breath- 



