THE ETIOLOGY OP MALAEIAL DISEASES. 435 



fourth day in Cu lex. Referring to liis experiments with 

 human parasites, they write, " Verisimilmente i due 

 mosquitos coli ali uiacchiate nei quali il Ross in India 

 trovo stadi di sviluppo simili a quelli del proteosoma (3° 

 giorno circa) appartenevano pure alia specie Anopheles 

 claviger, Fabr." (This statement is of interest in view 

 of Grassi's subsequent claim that Ross might very well 

 have been working with- insects belonging to the genus 

 Culex, and not with Anopheles at all.) They, more- 

 over, consider that Ross had not certainly determined 

 the development of the crescents in his mosquitoes, for 

 his observations had been broken ofP at too early a date ; 

 besides which the insects might have infected themselves 

 with haeinatozoa from some other animal. We have seen 

 that the latter supposition is unwarranted, because Ross's 

 Anopheles were raised from larvse. Moreover they 

 themselves neglect to state that they raised their Ano- 

 pheles from larvae, so we must presume that they did 

 not. 



Infection Experiment on Man. — In a foot-note to the 

 above publication it is reported that the authors had 

 successfully infected a person with tertian fever by 

 means of infected A. claviger, collected at Maccarese. 



December 22nd, 1898, Grassi, Bignami, and Bastianelli 

 follow the development of crescentic parasites 

 in Anopheles claviger to the formation of *' sporo- 

 zoites," the escape of the latter into the coelom of the 

 insect, and their accumulation in the salivary gland. 

 The development was found to be slower at 20° to 22° 

 than at 30° C. The fully developed capsules measured 

 70 ju, the sporozoites measured 14 fx. The process of 

 development, the size of the fully developed capsules, 

 and of the sporozoites, were the same as Ross had 

 observed in Proteosoma. 



The development of tertian parasites was observed to 

 take place in A. claviger up to the fifth day. 



February 2nd, 1899, Koch published a prelimiiiaiy note 



