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Artefacts from Blood Smears

Vegetable Cells Resembling Haematozoa (Text-figures 3 and 4)

Vegetable Cells Resembling Haematozoa (Text-figures 3 and 4).

Text-figure 3

Text-figure 3

Vegetable cell from a blood smear of Cygnus atratus. Two erythrocytes figured for size comparison.

Text-figure 4

Text-figure 4

Vegetable cell superficially resembling a spore of Sarcocystis, from a blood smear of Porphyrio poliocephalus. An erythrocyte is figured for size comparison.

A large number of blood smears were taken from game birds shot in the vicinity of Lake Wairarapa during May, 1947. Many of these were obtained by approaching sportsmen for permission to examine the birds they had shot. Most of the shooters were unwilling for a dissection to be carried out to allow blood to be obtained from the heart, so that smears usually had to be prepared from a superficial vessel or from shot wounds. Thus many of the preparations became contaminated with vegetable cells and bacteria. One dividing vegetable cell (Text-fig. 3), found in a smear from the Australian black swan Cygnus atratus (Latham), has (as seen in a Giemsa preparation) light blue cytoplasm and two red-staining nuclei. This cell bears a remarkably close resemblance to an artefact described by Bousfield (fig. reproduced by Wenyon, 1923) from a splenic smear from a case of kala-azar in the Sudan.

Text-fig. 4 illustrates another vegetable cell. probably a fungal spore, from a blood smear from a pukeko, Paryphyrio poliocephalus (Vieillot). This cell (Giemsa preparation) is bounded by a red-staining capsular wall and has a deep red "polar cap" at each end. The cytoplasm has a maculated appearance, and is divided into three clearly demarcated blocks. It is stained deep blue, and contains a number of deep red granules. The organism resembles a spore of Sarcocystis in its shape (curved, one end being more pointed than the other), in its measurements (15.9μ by 4.0μ), and in having polar caps. Spores of Sarcocystis, however, are not page 5 three-chambered. Careful focusing established that the organism in question had alighted on the slide following smearing, for it is in sharpest focus at a level above that of the plasma on which it rests.