1902.] Terminology for the Stages of the Malaria Parasite. 75 



penetrate, each one, a red corpuscle. The history of this process has 

 not been observed. As soon as it has entered a red corpuscle the 

 exotospore loses its needle-like shape and becomes amcebiform. I 

 apply to it the name I proposed some years ago for similar amcebiform 

 spores in other Protozoa, namely, Amcebula.* 



3. The Amcebula exhibits amoeboid movements within the red cor- 

 puscle, enlarges and finally breaks up into spherical spores, which are 

 liberated with destruction of the red corpuscle. It seems to me 

 nnnecessary to have a special name for the star-like or other con- 

 dition of the Amcebula when in course of breaking up into spores; 

 but the spores so produced require a special name which shall 

 emphatically distinguish them from the Exotospores. I call them the 

 Enblemospores, in reference to the fact that they are produced by a 

 process of division which occurs in the blood of the malaria-stricken 

 human being. 



4. The Enhsemospores penetrate fresh red blood-corpuscles, and after 

 a certain growth as amoebulse break up into a new crop of Enhgemo- 

 spores, by which the infection of the red corpuscles is extended. This 

 process appears to go on for several generations and for a varying 

 duration of time. But owing to conditions and at a period of the 

 infection which has not been precisely ascertained, some (or all ?) of 

 the amoebul&e derived from Enhaemospores cease to break up into 

 spores. Instead of carrying out that process they enlarge, and in the 

 case of the sestivo-autumnal parasite (Laverania prcecox) become sausage- 

 shaped or, as it has been termed, crescent-shaped. This change of 

 form is accompanied by a destruction of the red corpuscle and the 

 formation of granules of dark pigment within the parasite. It seems 

 best to term this phase the " crescent " or " crescent-sphere," the 

 latter term being applicable to those species in which the form is not 

 markedly crescentic. 



5. The crescents or crescent-spheres remain quiescent in the human 

 blood. They are, however, of two different natures — male and female. 

 It is not possible to distinguish with any certainty the male from the 

 female crescents whilst they remain in the human blood-vessels. But 

 it is these bodies which are destined to be swallowed by the Anopheles 

 mosquito, and to carry on further the life-history of the parasite. 



The crescents are therefore the sexual phase of the parasite. When 

 the crescents are swallowed by a mosquito (of an appropriate species), 

 they undergo two different modes of development, determined by the 

 fact of their sex. Both sexes become spherical, and may now be called 

 respectively " egg-cell," and " sperm-mother-cell." 



From the periphery of the sperm-mother-cell, now floating in the 

 mosquito's stomach, there are developed with surprising rapidity six or 

 seven spermatozoa, which for a time remain attached to the residual 

 * ' Encycl. Britann.,' Article " Protozoa." 



