120 



FERTILIZATION OF THE FROG'S EGG 



Tabulate the data as follows: 



Indicate total number of eggs/number cleaving = percentage 



REFERENCES 



APLINGTON, H. W. , 1957 - "The insemination of amphibian body cavity and oviduccal eggs. " J. Ohio Sci. 57-91-99. 

 BATAILLON, E. G TCHOU-SU, M. , 1934 - "L'analyse experimentale de la fecondation et sa definition par les processes cin- 



etiques. " Ann. des Sc. Nat. Zool. 17: 

 CLARK, ]. M. , 1936 - "An experimental study of polyspermy. " Biol. Bull. 70:360. 

 COSTELLO, D. P. , 1940 - "The fertilizability of nucleated and non-nucleated fragments of centrifuged Nereis eggs. " Jour. 



Morph. 66:99. 

 DALCQ, A. , 1928 - "Les Bases Physiologiques de la Fecondation." Paris. 

 FANKHAUSER, G. G C. MOORE, 1941 - "Cytological and experimental studies of polyspermy in the newt, Triturus viridescens. 



Jour. Morph. 68:347. 

 LILLIE, F. R., 1919 - "Problems of Fertilization." Univ. Chicago Press. 

 van OORDT, P.G.W.J., 1956 - "Regulation of the spermatogenetic cycle in the common frog, Rana temporaria. " 116 pp., 



G. W. van der Weil & Co. , Amheim. 



"The hiiiJian iin)id is first confronted with the effect and not with the 

 cause. It is only after the effect is defined that reasons for (or, more 

 correctly, events preceding) the effect are sought. The relationship 

 between the two is then clarified through an analysis of the intermediate 

 steps, usually referred to as the 'niechanism of action', or, for disease, 

 'pathogenesis'. There are few. if any, si)nple or single causes in biology. 

 There are, instead, complex situations and environments in which the 

 probability of certain events is increased. " 



M. B. Shimkin. Jour. Chron. Dis. 8:38. 1958. 



"Science does not explain anything. Science is less pretentious. 

 All tliat falls within its mission is to observe phenomena and to describe 

 them and the relations between them. 



A. J. Lotka. 1925 



