ENDOTHELIUM IN TISSUE CULTURES 47 
surface tension pull. This striation was similar to, but not so 
marked as that seen in the smooth-muscle cells in cultures, and 
it suggests that there is an unusual amount of contractile sub- 
stance in endothelium which is interesting in connection with 
recent physiological work on the contraction of capillaries by 
Dale, Krogh, and Hooker. 
The endoplasm became very finely granular on coagulation 
and in it were embedded most of the mitochondria and granules. 
BIBLIOGRAPHY 
Burrows, M. T. 1910 The cultivation of tissues of the chick embryo outside 
the body. J. Am.M. Ass., vol. 55. 
1911 The growth of tissues of the chick embryo outside the animal 
body, with special reference to the nervous system. Jour. Exp. 
Zool., vol. 10. 
1912 Rhythmische Kontraktionen der isolierten Herzmuskelzelle 
ausserhalb des Organismus. Miinchen. med. Wochnschr., No. 27. 
CarRREL, A., aNnDM.T. Burrows 1911 a Cultivation of tissues in vitro and its 
technique. J. Exper. Med., vol. 13. 
1911 b Cultivation in vitro of thyroid gland. J. Exper. Med., vol. 13. 
CHAMBERS, R. 1917 Microdissection studies. II. The cell aster: a reversible 
gelation phenomenon. Jour. Exp. Zodl., vol. 23, pp. 483-504. 
Conapon, E.D. 1915 The identification of tissues in artificial cultures. Anat. 
Rec., vol. 9. 
ErpMANN, Roopa 1917 Cytological observations on the behavior of chicken 
bone-marrow in plasma medium. Am. Jour. Anat., vol. 22. 
Foot, N. 1912 Ueberdas Wachstum von Knochenmark in vitro, etc. Beitr. z. 
path. Anat., Bd. 53. 
Harrison, R. G. 1907 Observations on the living developing nerve fiber. 
Anat. Rec., vol. 1. 
1910 The outgrowth of the nerve fiber as a mode of protoplasmic 
movement. Jour. Exp. Zodl., vol. 9. 
INGEBRITSEN, R. 1913 Studies on the degeneration and regeneration of axis 
cylinders in vitro. J. Exper. Med., vol. 17. 
LamsBertT, R. A. 1912 Variations in the character of growth in tissue cultures. 
Anat. Rec., vol. 6. 
Levi, G. 1916a Sull’ origine delle reti nervose nelle colture ditessuti. Rend. 
d. R. Accademia dei Lincei, vol. 25. 
1916 b Migrazione di elementi specifici differenziati in colture di 
miocardio e di muscoli scheletrici. Arch. per le Sci. Med., vol. 40. 
1917 Connessioni e struttura degli elementi nervosi R. Accademia 
dei Lincei. ' 
1919 Nuovi studi su cellule coltivate ‘in vitro.’ Arch. ital. di Anat. 
e di Emb., vol. 16. 
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