THE .-ETIOLOGY OF MALARIAL DISEASES. 433 



Medical Association Meeting at Edinburgh (July) on 

 behalf of Ross regarding further experiments with 

 Proteosoma. These observations showed that the 

 encapsulated parasites^ on reaching a certain size, rup- 

 tured and emptied their contents into the coelom of the 

 insect. The contents of the ruptured capsules consisted 

 of miuute spindle-shaped bodies, aud these bodies sub- 

 sequently accumulated in the salivary gland of the 

 insect. When this had occurred the insects were 

 capable of communicating the proteosomal infection to 

 healthy bii'ds. Of twenty-four sparrows exposed to the 

 bites of insects fed on mature parasites, twenty-two 

 became infected. 

 October 1st, 1898, Grassi reported that he had reason for 

 suspecting three species of Culicidas as being carriers of 

 malarial infection, claiming that they were confined in 

 their geographical distribution to those regions where 

 malaria was prevalent in Italy. The three species were 

 Culex penicillaris, Anopheles claviger (syn. 

 A. maculipennis), and a purported new species, 

 Culex malariae.^ It has since been proved that only 



' In his paper in the ' Poiiclinico ' (October 1st, 1898), Grassi writes : " In 

 conclusione, io sono d' avviso che ii Culex penicillaris e 1' Anopheles 

 claviger o per lo nienn il Culex penicillaris, lors' anche il Culex 

 nialarife, nella malaria si comportano conic le zecca nella febbre del Texas." 

 Grassi therefore makes a misstatement in a later paper (December 1st, 1900) 

 when lie writes, " Proclamai come indiziati due specie di culex, ma sopratutto 

 1' Anopheles claviger." It is curious that Grassi should subsequently have 

 continued to lay stress upon the geographical coincidence having led him to 

 the discovery of Anopheles claviger being a host of malarial parasites, 

 for two out of three species which he for this reason supposed must be hosts 

 were afterwards proved not to be such. He certainly considered A. claviger 

 at first to be of quite secondary importance ; we have his own words for it : 

 '* Certi casi di malaria sviluppatisi in Settembre a Locate Triulzi, nei quali 

 gli Anopheles di certo o non punsero o soltanto rarissime volte, denuuciano 

 decisamente come trasmissore il Culex penicillaris, enorma- 

 mente comune in tutti i luoglii malarici." (The italics are Grassi's.) 

 It is bnt, fair to Ross to state here that Grassi in his paper of the 1st of 

 October refers to the experiments made by Sniirh and Kilborne upon Texas 

 fever, and by Ross upon avian malaria as having been a " forte argumento" 



