DR. E. KLEIN ON THE SMALLPOX OF SHEEP. 
24 : 
E. Anatomical Investigation of Secondary Pustules. 
The examination of the secondary pocks, i. e. those of the general eruption, proves 
that the anatomical changes are substantially the same as in the primary. We find also 
here, at the outset of the process, thickening of the rete Malpighii and oedema of the 
corium, combined with the presence of lymph-corpuscles around the blood-vessels and 
extending hence into the distended lymph-canalicular system. 
The infiltration of the corium with lymph-corpuscles extends very soon, however, 
upwards into the papillary stratum and downwards into the subcutaneous tissue. In 
general it may be said that in the secondary pocks the whole process goes on much more 
rapidly, i. e. the stage of pustulation is much sooner reached than in the primary pocks. 
In most of the secondary pocks on the lip, the pustulation was seen to be going on 
as early as from two to four days after their appearance ; in those of the walls of the 
chest and abdomen the same thing was seen after from three to seven days. 
The infiltration of the subcutaneous tissue and corium was always found to be greater 
in the peripheral part than in the central. This was better marked in those pocks which 
were of long standing, i. e. which developed slowly, and particularly in those in which 
a central depressed and a peripheral thickened part could be distinguished. In the 
rete Malpighii the same immense overgrowth of the interpapillary processes occurred as 
in the primary pocks, and the cells of the middle layers showed the same tendency to 
become soon dropsical. I have not observed the formation of the horny stratum ; but 
in the central parts of many of the pocks I have noted the conversion of groups of 
epithelial cells into horny masses. 
As regards the interfascicular lymph-channels and the lymphatic vessels of the corium 
and their contents, I have only to repeat what I have stated as regards the primary 
pocks, viz. that one is able to follow the at first zooglcea-like masses of Micrococci into 
necklace-like filaments, which gradually become more and more branched, so as to form 
a delicate mycelium ; in some places the filaments of the mycelium bear conidia, and 
show the same fructification as those mentioned in the former section. The formation 
of the vesicles takes place in the same way as in the primary pocks, viz. by dropsical 
swelling and vacuolation of individual epithelial cells. 
The pustulation commences as a rule in the centre, and spreads rapidly into the 
periphery. The vesicles make their appearance in great numbers simultaneously, and 
are situated chiefly in the middle layers of the rete Malpighii, but are generally met 
with much nearer the corium than in the primary pocks. It is worth noticing that 
when the vesicles lie deep in the rete Malpighii, the expansion of the individual vesicles 
goes on at the expense of the interpapillary processes ; so that as the vesicles enlarge 
the interpapillary processes become shorter, until the line of demarcation between the 
rete Malpighii and the corium becomes almost as even as in. the normal state : in the 
latter case, therefore, the deepest cells of the rete Malpighii appear very much com- 
pressed, as if the rete had been dragged over the surface of the corium. There is 
