4i8 



GERMINAL ORGANIZATION 



INDUCTION PHENOMENA 



TABLE 4 



INDUCTION BY THE UNIN VAGI NATE D PART OF THE BLASTOPORE LIP 



(Compiled from Okada and Hama, 1944, Table I, p. 37) 



Cate- Number Brain Eye Olf. Bal- Oto- Spinal Pro- Endo- Tail Observations 

 gory of ves. placode anc- cyst cord nephros blast 



{see cases er Noto- 



texi) chord 



Somites 



1 1 

 16 



10 20 to 22 4 



10 

 13 



000 o 



3 II 12 to 16 o 



o 

 16 



16 



3 prosen- 

 cephalic 

 inductions, 

 explained 

 by regional 

 effect (near 

 host brain) 



8 4 cases with 

 a free lens 



A similar change has been recorded by Rollhauser-Ter Horst (1953). She has 

 repeated Mangold's experiment (p. 368) after a 90^ C heating of the fragments. 

 All of them became acrogenic. Her figures are interesting because of the evident 

 absence of any mesenchyme and the formation of the thickest part of the brain 

 at the closest contact of the implant. When this part was sufficiently thickened 

 (Fig. 80) it could be diagnosed as a rudimentary retina. 



'**nrj 



Fig. 80. Section of a sandwich in which acrogenic induction has been caused by a heated 

 part of the archenteron roof. See text. Br. (ret).- retine-like part of the brain; impl.- the dead 



implant. From Rollhauser, 1953. 



