94 THE ANIMAL PARASITES OF MAN 



and even rod-shaped pigment granules, which are actively turmoiled. 

 The polymitus form may be observed in the moist chamber. 



Irregularities sometimes occur also in the schizogony of this 

 species. The occurrence of two generations separated by about 

 twenty-four hours brings about tertiana duplex. 



FIG. 37. The development of the tertian parasite in the red blood corpuscles of 

 man ; to the right a " polymitus." (After Mannaberg.) 



3. Plasmodium, sp. 1 



Syn. : Laverania malarice, Gr. and Fel., 1890; Hcemamceba malarice prcecox 

 Grassi and Feletti, 1892, nee. Hcem. pvcecox, Gr. and Fel., 1890. 



This parasite is the cause of aestivo-autumnal or tropical fever (also 

 termed febris perniciosa s. maligna, tertiana maligna, febris tropica, 

 febris bidua, also febris quotidiana). The parasite is very small and 

 at most only occupies the third part of a blood corpuscle ; it is, 

 moreover, very active ; its pigment is very finely granular ; very 

 frequently also, at all events more frequently than in other plasmodia, 

 it assumes an annular form, the bodily substance in the centre 

 becoming attenuated and finally tearing through. The develop- 

 ment by schizogony normally occupies a period of forty eighty 

 hours, but the corresponding stages are seldom seen in the peri- 



1 The correct terminology of this species is still unsettled. Grassi and Feletti have 

 certainly called it Laverania malaria, but I see no reason that a particular species 

 should be set up. Besides, this species belongs to the genus Plasmodium. Within 

 this genus there already exists a species, " malariae " (Laveran), the quartan parasite, 

 and consequently the Grassi-Feletti denomination of species cannot again be used in 

 the same genus. For this reason other authors, such as Doflein, use the special term 

 of "praecox," which also originates from Grassi and Feletti, combined with H&mamoeba. 

 But in the same work (Boll. mens. Accad. Gicenia sc. nat. Catania, 1890, and C. f. B. 

 u. P., 1891, ix.) they term Hcemamceba pr&cox a haemosporidium of birds and one of 

 man. As the identity, however, of these forms has not been proved, and is not 

 even probable, the term Heemamceba prcecox can only be applied to one or the other, 

 and should hold good for the haemosporidium of birds as being the first mentioned in 

 the text. Neveu Lemaire (Les h6maioz. du paludisme, Pajis, 1901) uses the most prac- 

 tical term, i.e., H&matozoon falciparum, Welch. 



