1897] MICROSCOPICAL JOURNAL. 275 



convince the greatest skeptic. It must not be forgotten 

 that, in certain instances, two diseases may occur simul- 

 taneously. We have seen malaria in conjunction with 

 various ancient heart lesions, ulcerative endocarditis, 

 pulmonary tuberculosis, chronic nephritis, although 

 never with typhoid fever. The presence of malaria Plas- 

 modium makes possible positive differentiation from other 

 diseases ; e. g., the frequent error of overlooking or 

 misinterpreting an incipient pulmonary tuberculosis 

 attended with chills. Negative blood findings, in suspec- 

 ted malaria, are not definitive from one examination. 

 Not infrequently is more than one microscopic search 

 necessary for the positive exclusion of malaria. While 

 suggestive, then, a single negative finding is far from 

 conclusive. The parasites may be indistinguishable in 

 the first few days of the disease. In certain forms they 

 swarm in internal organs, avoiding the peripheral circu- 

 lation ; and lastly, in chronic and recurrent types they 

 are found with great difiiculty. 



Certain deformities in the red blood corpuscles are 

 often mistaken for plasmodia, e. g. crenations, poilkilo- 

 cytosis and vacuole formation. Not only can the more 

 intimate structure of the red blood discs retract, simula- 

 ting Plasmodia, but the exterior of the hemacyte is far 

 more plastic than is eommonly acknowledged, even to 

 the extent of protruding pronounced pseudopodia-like 

 processes. These are but too frequently mistaken for 

 parasites, being found in very many instances of appar- 

 ently otherwise normal blood. Vacuole formations are 

 characterized by their sharp contour and high luster. 



Melainferous leucocytes are readily distinguishable 

 from the plasmodia by their large nuclei and by their 

 amoeboid movenieut, always absent in adult parasites of 

 equal size. Unstained spores may be confused with the 

 blood plaques, which are, however, structureless and 

 contain no pigment. An Austrian pediatrist lost a docent- 



