226 
DE. E. KLEIN ON THE SMALLPOX OE SHEEP. 
I found and what I think I am justified in connecting with each other ; and if I com- 
pare these observations with those of other authors, I am inclined to believe : — 
(1) That the spheres figured by Sanderson, and some of those figured by Cohn, 
being identical with those figured by me, fig. 1, 2, and fig. 2, l, do not represent the 
true Micrococcus of the lymph of variola in its active condition, but represent rather a 
dropsical condition of the true active Micrococcus , which is a highly refractive spheroid, 
and appears solid and uniform under the microscope. 
(2) That the filaments stand in a genetical connexion with the development of Micro- 
coccus is shown by the observation of the lymph described on page 223, and repre- 
sented in fig. 2, i, 2, & 3. 
Section IV.— ANATOMICAL INVESTIGATION OE THE ERUPTION. 
A. Summary of previous Investigations. 
According to Luginbuhl* the pathological process in human smallpox consists in the 
penetration of the Micrococcus-yaxiolte into the skin, partly through the epidermis, 
partly through the hair-follicles and sweat-glands. By this means the inflammatory pro- 
cess known as smallpox, characterized by the following anatomical changes, originates : — 
1. In the epidermis an opaque swelling (Virchow) takes place, due to the cells of the 
rete Malpighii containing Micrococci. The nuclei of some of the epithelial cells, as 
well as some of the latter, become dropsical. The cells of the rete Malpighii, which are 
filled with Micrococci , show active proliferation ; they enlarge and their nuclei divide 
rapidly. Thus multinuclear giant cells are formed which are crammed full of Micrococci. 
In the deeper strata of the rete Malpighii, where the cells have only a very delicate cell- 
wall, the giant cells never become very large ; their membrane soon bursts and their 
nuclei become free : in the more superficial strata, however, the cells possess thicker and 
more resistant walls, and therefore the proliferation of their nuclei may go on for a much 
longer time. 
By the giant cells and those groups of nuclei just mentioned, as well as by the 
dropsical epithelial cells, spaces are formed in the rete Malpighii which represent the 
pustules. Certain conical giant cells in the deeper- strata of the rete Malpighii, while 
growing towards the corium, cause the communication of the latter with the spaces in 
the epidermis ; in this way cellular elements penetrate from the epidermis into the 
corium, whereas their previous place is occupied by a pale coagulable fluid. If the com- 
munication between epidermis and corium is once established, then the formation of the 
pustules makes rapid progress ; all around them appear new giant cells, which, however, 
do not reach a large size, but soon lose their former contents {Micrococci), and in its place 
contain - fibrinous coagula ; the neighbouring cells become compressed and dragged in 
manifold ways, so that finally a system of spaces is found, separated and penetrated by 
lumps (giant cells) and tracts (compressed epithelial elements). 
* “Der Micrococcus der Variola,” Arb. aus dem Berner path. Institut, 1871-72, p. 159. 
