393 



Nose, Pharynx and its Derivatives in Man 



cavity of the human mouth and nose in the early stages of develop- 

 ment, and hence at the suggestion of Dr. Mall I have made a series of 

 models of the cavities of the mouth and nose of the valuable series of 

 human embryos contained in his collection. The wax plate method of 

 Born * Avas used throughout the work. The embryos used represent 

 the first seven weeks of fcetal development. The magnifications were 

 varied to suit the thickness and size of the sections of the different 

 embryos used. In all the figures the cavities are represented as solid 

 models and hence it is necessary to bear in mind that one is looking at 

 a negative picture and not a positive one. The reverse is true, how- 

 ever, for the thyroid, thymus and salivary glands as these are solid 

 objects and are so represented by the solid models. In nearly all of 

 the models the mucous membrane was included. In' the model of 

 embryo XII and in one of the two made of embryo CLXIII only the 

 cavity was modeled. For the model of embryo XII I am indebted to 

 Dr. Mall. In making the illustrations to this paper an effort has been 

 made to preserve enough of the embryo to make the relations of the 

 model clear. At the same time details have been omitted in order to 

 avoid making the whole appear too complicated and obscure the most 

 im])ortant structures. For pictures of the entire embryos the reader 

 is referred to the beautiful illustrations of Bardeen and Lewis,' where 

 embryos CLXIII, CIX, and XXII are figured. These authors also refer 

 to the articles 23reviously written describing the embryos used for this 

 paper. The following table will show the comparative size and age of 

 the embryos used for these models: 



^Morph. Jahrb., ii ; Arch. f. mikr. Anat., xxii, p. 584. Also C. R. Bardeen, Johns 

 Hopkins Hospital Bulletin, Vol. xii, April-May-June, 1901. 



^Charles Russell Bardeen and Warren Harmon Lewis: Development of the Limbs, 

 Body-wall and Back in Man. This Journal, Vol. i. No. 1, 1902. 



