xiv CONTENTS. 



CHAPTER XIX. 



TERATOGENESIS 605 



Malformations Involving More Than One Individual 605 



Classification, Description, Origin 605 



Symmetrical Duplicity 606 



Origin of Symmetrical Duplicity 611 



Asymmetrical Duplicity 612 



Origin of Asymmetrical (Parasitic) Duplicity 614 



Malformations Involving One Individual 616 



Description, Origin 616 



Defects in the Region of Neural tube 616 



Origin of Malformations in the Region of Neural Tube .... 619 



Defects in Regions of the Face and Neck, and their Origin . . . 620 



Defects in the Thoracic and Abdominal Regions, and their Origin 622 



Malformations of the Extremities 622 



Causes Underlying the Origin of Monsters 624 



The Production of Duplicate (Polysomatous) Monsters . . . . . 625 



The Production of Monsters in Single Embryos 626 



The Significance of the Foregoing in Explaining the Production 



of Human Monsters 627 



References for Further Study 627 



APPENDIX. 



General Technic 629 



Procuring and Handling Material 629 



Fixation 631 



Hardening 633 



Preservation 633 



Embedding . . 633 



Section Cutting 634 



Staining 635 



Methods of Reconstruction 637 



References 638 



