GENEEAL OBSERVATIONS 



53 



corium. At this stage the corium has a perfectly plane 

 surface. 



The next stage will demonstrate the first step in the 



^■<^^' 



Fig. 26.— Section of Foot of Equine F(Etus, Seventy-seven 

 Days Old. 



The rete Malpighii rests on a plane corium ; the rent in the section is along 

 the line of tlie cells of the rete (Mettam). 



formation of the sensitive laminse,* The plain surface of 

 the corium has now become broken up, and what is noticed 





Fig. 27. — Section from Foot of Sheep Embryo. 

 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 echelon into its connective 



* Sheep embryo, exact age unknown. 



