162 THE STORY OF GERM LIFE. 



site is derived. It appears probable that water 

 serves in some cases as its means of transference 

 to man, and air in other cases. From some ex- 

 ternal source it gains access to man and finds 

 its way into the blood. Here it attacks the 

 red blood-corpuscles, each malarial organism 

 making its way into a single one (Fig. 34 a). 

 Here it now grows, increasing in size at the 

 expense of the substance of the corpuscle 

 (Fig. 34 a-f). As it becomes larger it becomes 

 granular, and soon shows a tendency to separate 

 into a number of irregular masses (Fig. 34 /). 

 Finally it breaks up into many minute bodies 

 called spores (Fig. 34^). These bodies break out 

 of the corpuscle and for a time live a free life in 

 the blood (Fig. 34 ti). After a time they make 

 their way into other red blood-corpuscles, develop 

 into new malarial amoeboid parasites, and repeat 

 the growth and sporulation. This process can ap- 

 parently be repeated many times without check. 



These organisms are thus to be regarded as 

 parasites of the red corpuscles. It is, of course, 

 easy to believe that an extensive parasitism and 

 destruction of the corpuscles would be disastrous 

 to the health of the individual, and the severity 

 of the disease will depend upon the extent of the 

 parasitism. Corresponding to this life history of 

 the organism, the disease malaria is commonly 

 characterized by a decided intermittency, periods 

 of chill and fever alternating with periods of in- 

 termission in which these symptoms are abated. 

 The paroxysms of the disease, characterized by 

 the chill, occur at the time that the spores are 

 escaping from the blood-corpuscles and floating 

 in the blood. After they have again found their 

 way into a blood-corpuscle the fever diminishes, 



