Tfie American X'ittinu'i4. 



ZOOLOGY. 

 Protozoa. — A number of articles appear every month on the sub- 

 ject of the malaria parasites, treating of their morphology, system and 

 pathogenity. Without going into details of all the original publica- 

 tions, the following may be taken as the most prominent views in re- 

 gard to the parasites. Laveran, the original discoverer of the parasite 

 which causes malaria, holds fast to the idea that only a single species 

 of Protozoa is concerned in the disease and that the various forms, 

 amoeba, crescent, etc., are only different stages in the development of 

 this parasite (Du Paludisme et de son Hematozoaire, Paris, 280 p. 

 6 Plates, 1891). Grassi andFeletti on the other hand admit two genera: 

 Halmamoeba and Laverania, the former with three species: H. prat- 

 cox, producing quotidian fever, H. vivax, producing simple or double 

 tertiana and H. malaria producing simple, double or triple quar- 

 tana ; Lavarania (the crescent) produces an irregular fever, (Central- 

 blatt f. Bakt. u. Parasitenkunde IX, p. 430, 1891). Halmamoeba is 

 supposed to correspond to Amoeba guttata and Laverania to A. radiata. 





parasites are classified as Rhizopods by these authoi 



Metschnikoff, L. Pfeiffer and others class them as Coccidia, whil 

 argues that they must belong to the Gregarina, because an adult form is 

 found free in the blood. In comparative Hamio-parasitology Celli and 

 Sanfelici (Ueber die Parasiten des rothen Blutkorperchenim Menschen 

 und in Thieren, Fortschritte der Medicin Bd. 9, 1891) draw the con- 

 clusion that the endoglobular parasitism is more obligatory— and hence 

 more highly developed in the Hsemogregarina of birds than in the 

 blood parasites of cold blooded animals, since in the latter, the parasiu* 

 thrive in the serum about as well as in the blood corpuscle. According 

 to these authors, the blood parasites of the frog, on arriving at a cer- 

 tain stage, either undergo sporulation, or develop into Drepanidium 

 of Ray Lankester. 1 



R. Pfeiffer (L. Pfeiffer, Ueber diePathogene Protozoen) has recently 

 made a very important discovery in regard to the development of 0* 

 cidium. According to these authors, gymnospores can be developed in 

 the growing Coccidium and serve to spread the infection to other cells. 

 Kruse has come to the same conclusion, but independently from 

 rteitter Kruse states the gymnospores can be formed at anytime 

 during the development of the parasite. These naked spores evidently 

 cannot spread the infection toother animal* t hi< work boing left to 

 the other spores (Dauersporen) w! ; aown. 



