372 CLINICAL BACTERIOLOGY. 



chlorid (from 35 .95 F. to 40 .104 F.) is 

 made. If the stool is formed, only the superficial layer of 

 mucus is examined. To fix and to preserve the amebae, a 

 portion of the material containing them is spread in as thin 

 a layer as possible upon a cover-slip, which is at once in- 

 troduced into absolute alcohol before it dries. The amebae 

 take stains less well than the bacteria ; so that in cover- 

 slip preparations they are distinguished by their pallor. 

 Methylene-blue is best suited for staining. The nucleus 

 stains more deeply than the protoplasm. More, however, 

 is to be learned from examination of fresh material than 

 from that of stained preparations, and if the observation 

 cover a protracted period, a warm stage is a useful adjunct. 



MALARIA. 



The exciting agent of malaria was discovered in 1880 by 

 Laveran in the blood of patients suffering from that dis- 

 ease. 



The parasites of malaria are unicellular forms of life 

 that at an early stage are endowed with ameboid move- 

 ment. They belong to the class of protozoa, the lowest 

 forms of animal life ; but there is no unanimity of opinion 

 with regard to their position in the zoologic scale. Metsch- 

 nikoff included them in the class of sporozoa, and con- 

 sidered them as coccidia. Others placed them among 

 gregarines, Kruse among the earliest, and he designated 

 them as hemogregarines. Still others believe them to be 

 amebae, and include them among the rhizopods. Mingazinni 

 suggests that the entire group of parasites that invade the 

 red blood-corpuscles be designated hemosporidia. In con- 

 sequence of this diversity of opinion a suitable name for the 

 parasites of malaria is wanting. The designation malarial 

 plasmodia, proposed by Marchiafava and Celli, is inappro- 

 priate, as plasmodium indicates a body resulting from the 

 confluence of numerous amebae, all of which preserve their 

 nuclei. 



Morphology and Biology of the Parasites of Mala- 

 ria (Plate I). The malarial parasites vary in size from one 

 to ten microns in accordance with the age of the individual cell. 

 The juvenile forms are in general flattened and disc-like, and 

 their shape varies with their ameboid movement. The mature 



