and Laboratory Methods. 1821 



GENERAL PHYSIOLOGY. 



RAYMOND PEARL, University of Michigan. 



Books and Papers for Review should be Sent to Raymond Pearl, Zoological Laboratory, 

 University of Michigan, Ann Arbor, Mich. 



Winkler, H. Ueber Merogonie und Befmch- The author has succeeded in fertilizing 

 tung. Jahrb.f. wiss. Bot. 36: 753-773, iQoi. i ^ j r ^ r ^u r 



-^ enucleated fragments of the egg of 



Cystosira barbata, a representative of the Fucaceae. Typical segmentation pro- 

 ceeds in such fragments, but at a slower rate than under normal circumstances. 

 The experiments of earlier investigators on the fertilization of enucleated frag- 

 ments of sea-urchin eggs were repeated. The author devised a very ingenious 

 method of obtaining nucleated and enucleated portions of these eggs. His pro- 

 cedure was as follows : the point of a pipette was drawn out to a capillary and 

 broken off at a point where its diameter was slightly greater than the diameter 

 of an Echinus egg. Then across the small opening so made a fine silk or cotton 

 fiber was stretched and fastened to the sides of the capillary with wax or shellac. 

 Then the pipette was filled from above with the water containing the eggs, and 

 the rubber bulb slipped on over the end. With weak pressure the eggs were 

 then forced out through the capillary end of the pipette, being divided into two 

 parts by the cross fiber as they passed out. Of course many of the eggs were 

 crushed and torn, but the operation was so simple and speedy that a large 

 number of clean cut &gg fragments containing no part of the nucleus could be 

 obtained in a short time. The author finds this method to be superior in prac- 

 tice to any of the others which have been advocated for the same purpose. 



Experiments on sea-urchin eggs were tried in which filtered sperm extract 

 was added to unfertilized eggs. The sperm extract was prepared by violently 

 shaking large quantities of spermatozoa in either distilled water or sea-water, and 

 then subjecting the mixture to a temperature of 70° C. This temperature killed 

 the spermatozoa. The liquid was then filtered and brought to the concentration 

 of sea-water. Segmentation in the unfertilized eggs was induced in some cases 

 as a result of the action of this extract, and the conclusion is reached that the 

 spermatozoa contain a substance (chemical) which induces division in the egg. 

 The final section of the paper is devoted to a theoretical discussion of the phe- 

 nomenon of fertihzation. r. p. 



Gles, W. J. Do Spermatozoa contain Enzyme ^n extensive series of experiments in 



having the Power of Causing Development which the effect of extracts of the 



of Mature Eggs ? Amer. Jour. Physiol. ^ ^ , ^ , ■ j. . j . j 



6: ';3-76 looi. testes of Arbacia punctulata and 



Strongylocentrotiis purpurattis on unfer- 

 tilized eggs of the same species, resulted negatively. No parthenogenetic de- 

 velopment was produced. A variety of ordinary methods for enzyme extraction 

 were used and proper precautions were taken against inducing parthenogenesis 

 by change of concentration of the medium. The author's conclusion is that if 

 any enzyme is concerned in the process of fertilization (as seems very doubtful 



