Jan., 1922] NICHOLS — METHODS OF HEALING IN ALGAL CELLS 
27 
7. A new plasma membrane grows inward from the old membrane and 
separates a portion of the protoplasm filling the puncture from the re- 
mainder of the cell. 
8. A new wall is gradually formed by this membrane, and the healing is 
complete. 
Oberlin College, 
Oberlin, Ohio 
LITERATURE CITED 
Chambers, R. ('17). Microdissection studies I. The visible structure of the cell proto- 
plasm and death changes. Amer. Jour. Physiol. 34: 1-2. 191 7. 
Goeppert, H. R., and Cohn, F. ('49). Ueber die Rotation des Zellinhalts in Nitella flexilis. 
Bot. Zeit. 7: 665-673, 681-691, 697-705, 713-719- 1849. 
Kite, G. L. ('13). Studies on the physical properties of protoplasm I. The physical 
properties of certain animal and plant cells. Amer. Jour. Physiol. 32: 146-164. 
1913. 
Klemm, P. ('94). Ueber die Regenerationsvorgange bei den Siphonaceen. Flora 78: 19-41. 
Taf. V, VI. 1894. 
Kiister, E. ('99). Ueber Derbesia und Bryopsis. Ber. Deutsch. Bot. Ges. 17: 77-83. Taf. 
VI. 1899. 
Harper, R. A. ('99). Cell-division in sporangia and asci. Annals of Bot. 13: 467-523. 
Pis. XXIV-XXVI. 1899. 
• ('00). Cell and nuclear division in Fuligo varians. Bot. Gaz. 30: 217-249. PL 
XIV. 1900. 
Noll, F. ('99). Die geformte Protein im Zellsafte von Derbesia. Ber. Deutsch. Bot. Ges. 
17: 302-306. 1899. 
Overton, E. ('90). Beitrage zur Histologic und Physiologic der Characeen. Bot. Centralbl. 
44: i-io. 1890. 
Seifriz, W. ('18). Observations on the structure of protoplasm by aid of microdissection. 
Biol. Bull. 34: 307-324. 1918. 
Topler, F. ('03). Ueber Vernarbung und Wundreiz in Algenzellen. Ber. Deutsch. Bot. 
Ges. 21: 291-300. Taf. XIV. 1903. 
West, G. S., and Hood, O. E. ('11). The structure of the cell wall and the apical growth 
in the genus Trentepohlia. New Phyt. 10: 241-249. 191 1. 
EXPLANATION OF PLATE III 
Fig. I. Nitella with escaping nonmiscible protoplasm. X 160. 
Fig. 2. Chaetomorpha with, escaping miscible protoplasm. X 160. 
Fig. 3. Nitella: section showing new membrane forming. X 160. 
Fig. 4. Chaetomorpha plasmolyzed to show the new (b) and old (a) membranes. 
X 160. 
Fig. 5. Chaetomorpha: section showing a new wall formed over the plug fifteen days 
after puncturing. X 160. 
Fig. 6. Chaetomorpha: section showing a new wall well formed three weeks after 
puncturing. X 160. 
