PARASITES IN MALARIAL FEVER 31 



limits. In some cases the number of spores found is 

 small in all the sporulating parasites seen. In others the 

 number of spores formed is large in all. Speaking 

 generally, it is much rarer to find the parasites with six 

 to eight spores than those with a larger number. 



(5) Effect on the red blood corpuscle : This certainly 

 varies, but does so as much from day to day in the same 

 patient as in different persons. Brassy bodies may be 

 very numerous on one day, but though the patient is not 

 treated and the parasites continue to be numerous, none 

 at all may be found two or three days later. 



(6) Toxic Effects. Haemolysis may be marked or very 

 slight, and in some countries these haemolytic effects are 

 very common and in others rare. In most forms of 

 malaria there are changes in the red cells similar to those 

 found in other diseases where toxic blood changes occur, 

 e.g. pernicious anaemia (Plate II, i 9). This may 

 indicate a difference in species. Other effects, such as 

 albuminuria, are common in some districts and rare in 

 others. In these cases no morphological differences in 

 the parasites can be demonstrated. It is possible that 

 there are different species of parasites, but it cannot be 

 considered as proved. Possibly the differences in toxic 

 effects of the parasites may be affected by variations in the 

 environment of the parasites during their sexual or exo- 

 genous cycle, as in different places different mosquitoes 

 serve as hosts, and slight alterations in temperature 

 markedly affect the rate of growth and development of 

 the parasites whilst developing in the mosquitoes. 



