jl^ HOWELL. [Vol. IV. 



of prolonged or extreme anaemia produced by repeated bleed- 

 ings. 



9. The leucocytes of the blood are derived from the lymph 

 leucocytes (lymphocytes). The latter enter the circulation 

 as small corpuscles with vesicular nuclei and scanty proto- 

 plasm, and are not amoeboid. They develop into larger cells, 

 with finely granular protoplasm which possess amoeboid move- 

 ments. These have at first an oval vesicular nucleus, which 

 afterwards becomes elongated and assumes a horseshoe or 

 spiral shape. From this last form the multinucleated cells are 

 derived by fragmentation of the nucleus. The fragmentation 

 of the nucleus is probably followed by the disintegration of the 

 whole cell. 



10. The fragmented nuclei after the disintegration of the cell 

 persist for a time in the circulation as the blood plates. 



LITERATURE. 



1. Wagner. Quoted from Neumann (Zeit. f. Klin. Med., 1881, Vol. III., 411). 



2. Weber. Quoted from Neumann (Zeit. f. Klin. Med., 1881, Vol. III., 411). 



3. Kolliker. Mik. Anatomic. II., 2, S. 589, 1S54. 



4. Erb. Arch. f. Path. Anat. u. Physiol, u. f. Klin. Med. (Virchow). Bd. 



34, S. 138, 1865. 



5. Neumann, a. Berlin Klin. Wochenschrift. No. 40, 1868. 



b. Arch, der Heilkunde. Bd. X., S. 68, 1869. 



c. Arch, der Heilkunde. Bd. XL, S. 11. 



d. Arch, der Heilkunde. Bd. XV., S. 441, 1874. 



e. Arch. f. d. ges. Physiol. (Pfluger). Bd. IX., S. no, 1874. 

 /. Archiv f. Mik. Anatomie. Bd. XL, S. 169, 1875. 



g. Archiv f. Mik. Anatomie. Bd. XIL, S. 793, 1876. 

 h. Zeit. f. KHn. Med. Bd. 3, S. 411. 1S81. 



6. Reichert. Beobachtungen ueber die ersten Blutgefasse u. deren Bildung 



so wie ueber die Bewegung des Blutes bei Fischembryonen. 1857. 

 (Quoted from Feuerstack.) 



7. Wenckebach, a. Journal of Anatomy and Physiology. Vol. 19, 1885. 



b. Archiv f. Mik. Anat. Bd. 28, 1886. 



8. Ziegler. Archiv f. Mik. Anat. Bd. 30, S. 643, 188S. 



9. Klein. Sitzungsberichte d. K. Akad. d. Wiss. Bd. 63, 1871. 



10. Balfour. Foster and Balfour. Elements of Embryology. London, 1883, 



p. 92. 



11. Gensch. Archiv f. Mik. Anat. Bd. 19, S. 144. 



12. His. Archiv f. Anat. u. Physiol. 1882, S. 62. 



13. Foa and Salvioli. Archivio delle Scienze Mediche. Vol. IV., p. I. 



14. Denys. La Cellule. IV., 203. 



15. Ranvier. Arch, de physiol. path, et norm. 1874, 429; 1875, i* 



