ON THE PATHOLOGY OF SHEEP-POX. 239 
germination, in consequence of which the interpapillary 
processes not only enlarge, but intrude in an irregular 
manner into the subjacent corium. At the same time, the 
cells immediately below the horny stratum begin to take 
part in the formation of the vesicular cavities, some of them 
enlarging into vesicles, while others become flattened and 
scaly, so as to form the septa by which the vesicular cavities 
are separated from each other. 
The whole of this process is well shown in fig 9,1 which 
Fic. 9. 
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1 (a) Stratum corneum, (4) superficial layer of rete Malpighit, (c) deep 
VOL. XV.—NEW SER, R 
