191 



very close apposition to the lens substance and protruded into the 

 lens cavity some time before the cavity because constricted i. e. prior 

 to the 69th hour. 



The evidence in favor of the second is, that the injury to the 

 ectodermal layer of the amnion was on the left side, where the yolk- 

 sac is attached to the embryo and since the embryo was transferred 

 to Flemming's solution, the yolk sac seized with forceps and removed 

 this manoeuvre may have inflicted an injury upon the amnion. 



Even if the cause of the amnion protrusion be mechanical the 

 fact still remains that it would have taken place within the egg. 



The presumptive evidence would justify the conclusion, that the 

 entrance into the lens-pit, of misplaced amniotic tissue would produce 

 pathological changes in the lens and that in this specimen the pro- 

 trusion had grown into the lens- vesicle. Furthermore an amnion 

 protrusion might produce malformations and even colobomas of other 

 parts. 



After the study of this case was completed I learned of Aurel 

 VON Szily's contribution^). 



This case differs from von Szily's in that, only one eye was 

 affected and probably through some local influence, even if we assume 

 that something abnormal had acted on the whole embryo. Again if the 

 dipping in of the amnion occurs as often as von Szily asserts then 

 surely it would have seen more frequently by other competent ob- 

 servers. 



Bonn, Biologisches Laboratorium. 



Bücheranzeigen. 



Ueher den chemischen Character des Befruchtungs Vorgangs und seine 

 Bedeutung für die Theorie der Lebenserscheinungen. Vortrag, geh. 

 a. d. Internat. Zool. -Kongreß zu Boston 22. Aug. 1997, von Jacques 

 Loeb. (Vorträge u. Aufsätze über Entwickelungsmechanik der Or- 

 ganismen, hrsg. von W. Roux, Heft 2.) Leipzig, W. Engelmann, 1908. 

 31 pp. Preis 80 Pf. 



Die Wirkung des Kerns (als Hauptoxydationsorganes der Zelle) 

 auf die Nukleinsynthese und die Bedeutung dieser für das Wachstum 

 und die Fortpflanzung führen eine der rätselhaftesten Eigenschaften der 

 Zellen, die automatische Eortpfianzung, auf eine wohlbekannte Tatsache 

 der Fermentchemie, die Autokatalyse, zurück. 



1) Ueber Amnioneinstülpung ins Linsenbläschen der Vögel. Anat. 

 Anz., Bd. 28, 1906, p. 231. 



