630 POPULAR SCIENCE MONTHLY. 



length. Richard has several times seen the fully developed para- 

 site emerge from its ' shell ' the remnant of the invaded red cor- 

 puscle to which it may remain attached, and which can only be 

 seen with great difficulty. Sometimes only the motile filaments 

 penetrate the envelope in which the body of the parasite remains 

 inclosed. In both cases the filament is seen to undergo active 

 movements, and when its extremity is caught in the fibrinous 

 reticulum the body itself oscillates. This movement may last for 

 an hour. Usually, however, no movement is observed, and the 

 corpuscles containing very small parasites never move. The in- 

 fected corpuscles become disorganized, the pigmentary collarette 

 is broken down, and a grayish mass inclosing some black gran- 

 ules remains. The pigment granules when set free are rapidly 

 picked up by the leucocytes; the melaniferous leucocytes are 

 therefore epiphenomena." 



Commenting upon the observations of Laveran and Richard, I 

 say, in the work just referred to: 



" We can not doubt that a true account has been given of what 

 the observers believe they have seen. But there is a wide field for 

 doubt as to the deductions made from the various observations 

 recorded; for in microscopical studies of the blood made with 

 high powers there is a great liability to error and to misinterpre- 

 tation of what is seen. We may question, for example, whether 

 the belief of Laveran and Richard that the appearances noted by 

 them are due to parasitic invasion of the blood-corpuscles is well 

 founded, without calling in question the accuracy of their obser- 

 vations." 



At the time this was written pathologists generally were not 

 disposed to attach much importance to the alleged discovery of 

 Laveran, and this was especially true in Germany and in those 

 countries in which physicians were in the habit of awaiting the 

 verdict of German bacteriologists before accepting anew "disease 

 germ." One reason for this failure to give proper consideration 

 to the discovery of Laveran was the fact that there was a rival in 

 the field. A year before the publication of Laveran's paper, giv- 

 ing an account of his observations, the distinguished German 

 pathologist Klebs, in association with the prominent Italian phy- 

 sician Tommasi-Crudeli, had announced the discovery of a bacil- 

 lus which they believed to be the cause of the malarial fevers, 

 and which they named Bacillus malaricB. Their experimental in- 

 vestigation was made in Rome with material obtained from the 

 malarious marshes in the vicinity of that city. 



The evidence offered in the original memoir of Klebs and 

 Tommasi-Crudeli in favor of the view that the bacillus de- 

 scribed by them is the cause of malarial fevers in man, is 

 derived from experiments made upon rabbits, in which culture 



