AN ANALYSIS OF THE EELATION BETWEEN, 

 GROWTH AND NUCLEAR DIVISION IX A 

 PARASITIC INFUSORION, OPALINA SP.' 



R. W. HEGNER, Ph.D. 



HSIANG-FONG WU, M.D. 

 National Medical, College of Pekixg, Chixa 



This investigation was undertaken for the purpose of 

 analyzing the relation between growth and nuclear divi- 

 sion in a species of OpaVma of the frog during the growth 

 period in the tadpole. The multinucleate condition of 

 Opalina and the absence of cell walls render it of par- 

 ticular value as material for the study of the phenomena 

 involved in nuclear division and growth. The specimens 

 used in our investigations were obtained by Dr. Charles 

 E. Simon from tadpoles collected at Chester, Nova Scotia, 

 during the summer of 1920. Unfortunately we are unable 

 to state either the species name of the Opalina or that of 

 the host. Dr. Maynard M. Metcalf, who has examined 

 the slides, thinks the Opalina is probably an niidoscrilied 

 species. The material was well fixed in Srliaii.liiin 's 

 solution and beautifully stained with iron-lu'inatoxylin. 



A sufficiently large number of specimens (455) wore 

 drawn with a camera lucida so as to furnish reliable re- 

 sults when measurements were treated by statistical 

 methods. The area of the drawings was determined with 

 a planimeter and the correlation with tlio nuclear number 

 determined. Table I is the correlation talile for the 

 nuclear number and area of .'Ul sjieeiinciis. The area of 

 the drawings, which were made at a iiiaunilieation of G50 



