GENEKAL OBSEEVATIONS 



45 



ficial layers of the cells composing it are hard and horny, 

 while the deeper layers are soft and protoplasmic. These 

 latter form the so-called Rete Mucosum of Malpighi. 



Commencing from below and proceeding upwards, we 

 find that the lowermost cells of the rete mucosum, those 





Fig. 23. — Vertical Section of Epidekmis (Human). 

 Ranvier.) 



(After 



J, The horny layer of the epidermis ; B, the rete mucosum ; a, the columnar 

 pigment-containing cells of the rete ; b, the polyhedral cells ; c, the 

 stratum granulosum ; d, the stratum lucidum ; c, swollen horny cells ; 

 /, the stratum squamosum. 



that are set immediately on the corium, are columnar in 

 shape. In animals that have a coloured skin these cells 

 contain pigment granules. Directly superposed to these 

 we find cells which in shape are polyhedral. Above them, 

 and forming the most superficial layer of the rete mucosum, 



