508 PROTOZOA 



the peripheral blood in the early stages, it is necessary to be thoroughly 

 familiar with the young aestivo-autumnal forms. Chromatin staining for 

 them cannot be too much recommended, as there is little that is charac- 

 teristic about them when they have been stained with methylene blue 

 alone. Many a serious error has been made by adhering to the an- 

 tiquated idea that parasites should be looked for in the fresh blood, 

 as these young, non-pigmented, so-called hyaline forms cannot be readily 

 recognized by the inexperienced, while it is an easy matter to know 

 and classify them when properly stained. 



The Quartan Parasite. 



The recognition of the quartan parasite in its early stages in the 

 fresh blood is not as difficult as that of the tertian form, but in stained 

 preparations it is often indistinguishable from the latter. The living 

 amoeboid young form is more refractive than the young living tertian 

 form, more like the sestivo-autumnal form, and it is just as sluggish in 

 its movements. Here, too, the corpuscle is often shrunken and looks as 

 if it contained more haemoglobin than in the case of infection with the 

 tertian parasite. 



The growing parasite shows fewer pigment granules than the corre- 

 sponding tertian one, and it is apt to form a band across the infected cor- 

 puscle. Segments are few in number, as a rule, and the parasite remains 



DESCRIPTION OF PLATE III. 



1. Typical young tertian form ; the corpuscle shows incipient degeneration ; corpuscle to left 

 above shows a blood platelet. 



2. Abnormal young form, showing small accessory chromatin body. 



3. Two parasites ; one a normal young form; the second large form in crenated corpuscle is an 

 unusual abnormal form with very large achromatic area. 



4. 5, 6. ^Estivo-autumnal parasites; single, double, and triple infection; central elongated 

 chromatin bodies. These forms are about the largest usually seen in the peripheral blood ; no 

 degeneration of corpuscle. 



7. Tertian parasite, about ten hours old ; marked degeneration of corpuscle. 



8. Double infection of ff corpuscle in tertian fever ; marked degeneration of corpuscle. 



9, 10, 11. Large tertian parasites showing division of chromatin previous to segmentation. 

 12 and 14. Complete segmentation of tertian parasite. 



13. Double infection of corpuscle, one parasite reaching maturity, but showing unusually small 

 segments ; the second one atrophied. 



15. Tertian parasite, old case ; while the parasite is only half-grown, the chromatin has split into 

 several compact masses. Degeneration of infected corpuscle. 



16. Dwarfed tertian parasite, smaller than a red corpuscle, but showing five compact chromatin 

 bodies ; resemblance to quartan rosette. 



17. Microgametocyte of tertian malaria ; prominence of blackish pigment surrounding a large 

 achromatic zone in which the microgametes lie coiled up. 



18. Tertian macrogametes. 



19 to 23. Crescentic bodies of aestivo-autumnal malaria. 



19. Typical gamete ; pigment surrounding achromatic area ; no chromatin shown; the "bib" is 

 present. (Male?) 



20. Semiovoid gamete. (Female?) 



21. Pigment removed. Elliptical achromatic area in which the microgametes are seen. 

 22 and 23. Pigment removed ; chromatin more compact ; possibly female elements. 



24. From a case of pernicious malaria with rich infection ; only hyaline forms in peripheral blood. 

 Below a large blood-platelet. 



NOTK. As the amplification is not uniform a comparison of the parasites with the blood corpuscles 

 shown should be made in order to have a correct conception of their size. 



