CONTENTS. 



Page 



Introduction; Polyvalent structures; Factors of their further development 3 



Mesenchyme of the spleen, of the allantois, and of the thymus (3 



Mesenchyme of the muscles ,. 



Mesenchyme of the sex-glands , ., 



Mesenchyme of the kidneys , s 



Mesenchyme in other regions of the embryo body 23 



Conclusions .,_ 



Bibliography ... 



Explanations of plates -.o 



2 



