1891.] The Pathogenic Fungus of Malaria. 199 



V. "On the Demonstration by Staining of the Pathogenic 

 Fungus of Malaria, its Artificial Cultivation, and the 

 Results of Inoculation of the same." By Surgeon J. FENTON 

 EVANS, M.B. Communicated by Professor VICTOR HORSLEY, 

 F.R.S. (From the Laboratory of the Brown Institution.) 

 Received February 7, 1891. 



(Abstract.) 



The discovery of organisms constantly concomitant with manifes- 

 tations of malaria was made by Laveran in 1880. 



His researches have since been corroborated and amplified by 

 numerous observers in different parts of the world, amoug whom 

 must be mentioned, Marchiafava, Celli, Golgi, and Guarnieri, in Italy ; 



uncilman, Osier, and James, in America ; and Vandyke Carter, in 



dia. The foreign structures which all of the above-named inves- 

 igators agree in finding in the blood during or after attacks of ague 



ay be grouped into the following classes : 



1. " Cystic" bodies or spores, 2 to 11 [t in diameter, round, trans- 



parent, encapsuled bodies of variable dimensions. 



2. Crescentic bodies, 8 to 9 /* long and 3 fi broad. 



3. Plasmodia malariee, organisms as variable in size as the 



" cystic " bodies or spores, possessing the power of amoeboid 

 movement, and so closely associated with the red blood 

 corpuscle that hitherto the majority of observers have con- 

 sidered them to be parasites situated within the red blood 

 cells. 



4. Mobile filaments, 21 to 28 /* long. 



Despite the general concord of the observations, the subject has not 

 advanced beyond the stage of recognition of these structures in the 

 blood, and that, too, only while in the fresh state. 



No method had hitherto been discovered of preparing permanently 

 stained specimens of the organism. 



It had never been isolated or classified, nor when thus separated 

 had its pathogenic qualities ever been tested by experiments on lower 

 animals. 



It was thus clear that much remained to be done, and in the paper 

 are recounted the attempts made to place the subject on a satisfactory 

 footing. The author has found that it is possible to stain the or-" 

 ganisms with an anilinised alkalised solution of rosanilin hydro- 

 chloride after treatment with bichromate of potash, and after 

 treatment with dilute sulphuric acid by an anilinised alkalised 



'ution of Weigert's acid fuchsin. 

 TOL. XLIX. p 



