x CoNTENTS 
PAGE 
XVI. Analysis of the Original Method of Producing Arti- 
ficial Parthenogenesis by Hypertonic Solutions 
Alone - - - - - - . - - 159 
XVII. Membrane Formation and Cytolysis - - - 173 
XVIII. The Fertilizing Effect of Foreign Blood and Foreign 
Cell Extracts - - - - - - - 191 
XIX. The Fertilizing Effect of Sperm Extract - - - 20156 
XX. The Mechanism of the Formation of the Fertilization 
Membrane - - - - - - - = i ae 
XXI. Is Development of the Sea-Urchin Egg Possible with- 
out Membrane Formation or without the Second b 
(Corrective) Factor? - - = - = - 219 
XXII. The Action of the Spermatozoon upon the Egg. I. 
Heterogeneous Hybridization - - - - 225 
XXIII. The Action of the Spermatozoon upon the Egg. II. 
The Combination of Artificial Parthenogenesis and 
Fertilization with Sperm in the Same Egg” - - 233 
XXIV. Conditions for the Maturation of the Egg - - 243 
XXV. Artificial Parthenogenesis in the Eggs of the Starfish- 248 
XXVI. Artificial Parthenogenesis in the Eggs of Annelids - 257 
XXVII. Experiments with the Eggs of Molluscs - - - 267 
XXVIII. Artificial Parthenogenesis in the Eggs of Frogs - - 271 
XXIX. Artificial Parthenogenesis in Plants - - - - 277 
XXX. Preservation of the Life of the Hes by the Act of 
Fertilization - - - - - - 281 
XXXI. Artificial Parthenogenesis and Heredity - - - 291 
XXXII. Can an Embryo Develop from a Spermatozoon? - 303 
