D. Ward Cutler 
145 
Nlrenstein, E. (1905). Zeitschr. f. allgem. Physiol, v. 
Prantl, H. (1907). Arch.f. Protistenk. viii. 281. 
Rhumbler (1910). Arch. Entwicldungsmech. xxx. 194. 
Schaudinn, F. (1903). See ref. Parasitol. x. 311. 
Smith, M. and Mathews, J. R. (1917). Ann. Trop. Med. and Parasitol. x. 
Woodcock, H. M., Penfold, W. and Drew. A. H. (20. v. 1916). Brit. Med. Journ. \/ 
Werner (1908). Arch.f. Schijfs. u. Tropenhyg. xii. 
Wenyon, C. M. (1915). See ref. Parasitol. x. 311. 
DESCRIPTION OF PLATE VII. 
The figures have been drawn from permanent preparations with the aid of a Camera Lucida 
and the following optical apparatus: Zeiss apochromatic oil immersion objective 2 mm. (N.A. — 1-3) 
and compensating oculars 6, 12 and 18. Critical illumination was always employed. 
Figures 1-27, with the exception of figs. 2, 14, 15, 16, 17, are drawn from specimens fixed 
with Schaudinn’s sublimate alcohol, the others are from specimens fixed with Bouin’s fluid. 
Figs. 7, 11, 14, 22 are from specimens stained with Fleming’s tricolour, the remainder from speci¬ 
mens stained by Heidenhain’s iron haematoxylin method. The magnification of figs. 1-22 
approximately 850 diameters, figs. 23-27 approximately 1800 diameters. 
Figs. 1-3. Vegetative amoebae showing different appearances of the karyosome, and the alveolated 
cytoplasm. 
Fig. 4. Amoeba with pseudopodia composed of a meshwork of endoplasm. 
Fig. 5. Vegetative form with typical “tetragena” nucleus. 
Figs. 6-14. Successive stages preparatory to division, all with the exception of fig. 14 from the 
human intestine, fig. 14 from a culture form. In fig. 11 the “histolytica” type of nucleus 
is seen. 
Fig. 15. Specimen from cat; karyosome with two chromatin granules, which might be interpreted 
as a divided centriole. 
Figs. 16-20. Successive stages in division of the nucleus, specimens from human intestine. In 
fig. 20 the nucleus is abnormally large. 
Fig. 21. Two nucleate amoebae from a culture form. 
Fig. 22. Two nucleate amoebae from the human intestine, extruded chromatin in the cytoplasm. 
Figs. 23, 24. Precystic stage, E. rninuta, fig. 23 from specimen in faeces: the nucleus is abnormally 
large. Fig. 24 from culture form. 
Figs. 25, 26. Nucleus preparing to divide in the cyst, in fig. 26 the chromatoid bodies and vacuole 
have appeared. 
Fig. 27. Nuclear extrusion. 
• 
Figures 28-38 were drawn from specimens fixed with Schaudinn’s sublimate fluid and stained 
with Heidenhain’s iron haematoxylin. Figs. 28-38 are magnified approximately 1800 diameters: 
fig. 40 approximately 2500 diameters and fig. 39 approximately 1000 diameters; the remainder 
approximately 850 diameters. 
Figs. 28, 29, 31-34. Stages in division of the nucleus. 
Fig. 35. Binucleate cyst. 
Fig. 36. Last stage in division of the two nuclei to form the quadrinucleate cyst. 
Figs. 30, 37, 38. Quadrinucleate cysts. 
The above figures have been drawn from specimens from the human intestine. 
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