MALARIAL PARASITE. 661 



reaction is due to the action of these toxins. 

 Methylene blue has the power of preventing seg- 

 mentation of the parasites (Ehrlich), and it has 

 been shown that the paroxysm of fever may be 

 averted by administering methylene blue at the 

 proper time. This corroborates the view that the 

 segmentation of the parasites causes fever in some 

 way. The paroxysm would seem to represent the 

 time required for the exhaustion of the toxins set 

 free at the time of the cell division. 2 



On the basis of the conditions just cited, the 

 brief duration, sharp limitation and regular re- 

 currence of the paroxysms in tertian and quartan 

 fevers become intelligible. In a similar manner 

 the longer paroxysms and shorter intermissions 

 which characterize the typical aestivo-autumnal in- 

 fection (i. e., in first attacks) are related to the 

 habits of division of the corresponding parasite. 

 All the cells do not divide within a relatively short 

 period, as in tertian and quartan fevers, but the 

 process of division rather stretches out over from 

 twenty-four to forty-eight hours. This accounts 

 for the longer duration of the paroxysm. When 

 the last cells of one generation are dividing, per- 

 haps after the fever has gone down, the first cells 

 of the succeeding generation are well oji toward 

 maturity and their division within a short time 

 inaugurates a new paroxysm; the brief intermis- 

 sion would seem to be explained by this condition. 

 As the disease lasts longer, or as relapses develop, 

 the periods of division of the parasite are less 



2. Rosenau, Parker, Francis and Beyer produced a typical 

 paroxysm in a healthy person by injecting filtered serum 

 taken from a tertian patient during the chill This was 

 intoxication, not infection 



