XIX] PROTOZOA CAUSING DISEASE 501 



by his numerous researches was .able to show that the 

 various forms of malarial fever are due to various species of 

 the parasite, at any rate that in the different forms of inter- 

 mittent fever the time in which the parasite passes through 

 all the above-mentioned phases of its development is 

 different, and stands in a definite relation to the form of the 

 fever. Thus Golgi found that in the febris quartana the 

 parasite from its first appearance in the red blood-corpuscle, 

 that is, from the onset of a febrile attack, through the com- 

 plete segmentation of the full-grown parasite into the 

 sporules, and to the disappearance of these from the 

 general circulation, i.e., till the end of the febrile stage, re- 

 quires three days, whereas in the febris tertiana it requires 

 only two days. Besides, there are certain slight morpho- 

 logical differences between the parasite in the febris quartana 

 and in that of the tertiana, as also differences in the mode of 

 segmentation {seeY\g%. 200 and 201). As to the parasite in 

 the fever of irregular type, Golgi shows that also in this the 

 time occupied for passing through its phases is irregular, 

 either too rapid or too slow. The crescentic form of the 

 parasites mentioned by Laveran and Marchiafava and Celli 

 are present only in fever of irregular type, and are really an 

 atypical form in the development of the parasite. So also 

 the flagellate forms seen by Laveran are atypical forms. 



Whether in these different forms we have really to deal with 

 different species of the same group of parasites, as Golgi inclines 

 to think, or rather with differences in the life-history of the 

 same species caused by unknown conditions, e.g., individual 

 person, different tissue, season, locality, &c., is not decided. 



Canalis {Studl della Infezione malarian, Torino, 1889) 

 Studied the atypical forms of malarial fever, characterised by 

 longer or shorter febrile intervals. He found in these cases 

 an endoglobular form of the Plasmodium malarise, which has 



