GENERAL OBSERVATIONS 53 
corium. At this stage the corium has a perfectly plane 
surface. 
The next stage will demonstrate the first step in the 
Fic. 26.—Srction oF Foot or Equine Fatus, SEvVENTY-SEVEN 
Days Op. 
The rete Malpighii rests on a plane corium ; the rent in the section is along 
the line of the cells of the rete (Mettam). 
formation of the sensitive lamine.* The plain surface of 
the corium has now become broken up, and what is noticed 
Fic. 27.—SEcTION FRoM Foot oF SHEEP EmpBryo. 
It shows a pronounced epithelial ingrowth into the corium (Mettam). 
is that the broken-up appearance is due to the epithelial 
cells irrupting and advancing en échelon into its connective 
* Sheep embryo, exact age unknown. 
