64 3I0SQUTT0ES 



eludes other blood-sucking- insects from being possible 

 hosts of malarial parasites on the strength of his sup- 

 posed geographical agreement. 



6. Since the geographical distribution of Anopheles in 

 England is wider than the former distribution of ague in 

 that country, we are forced to conclude that it is not a 

 matter of the geographical distribution of Anopheles as 

 much as of their numerical distribution. 



7. Our observations having proved the existence of 

 Anoidieles in non-malarious districts, we believe that they 

 will explain the occasional occurrence of ague in out of 

 the way places, Avithout making it necessary to assume 

 that malaria-bearing moscpiitoes have been freshly im- 

 ported, for, given suitable conditions of temperature and 

 the requisite number of Anopheles, a malarious subject 

 coming from other parts might w^ell infect the local in- 

 sects, wdiich in turn would spread the infection to healthy 

 persons. 



8 We would suggest to those engaged in the investi- 

 gation of malaria in other countries, that they search as 

 carefully for Anopheles in non-malarious as in malarious 

 regions. More data as to the number of these insects in 

 various localities are certainly required, though Ave are 

 fully aware that numerical estimates permit of a consider- 

 able degree of error. Nevertheless, they would always 

 possess a relative value. 



Grassi has repeatedly asserted that the geographic dis- 

 tribution of Anopheles in Italy coincides with that of 

 malaria, and on the strength of their wdder geographic 

 distribution he excludes a number of blood-sucking creat- 



