DR. E. KLEIN ON THE SMALLPOX OF SHEEP. 
221 
in the lymph, of vaccine, as well as in that of sheep-pox, in a very ingenious manner from 
very numerous experiments (Comptes Rendus, vols. xlvii. & xlviii., February, October, 
and November 1868). 
Burdon Sanderson, confirming the accuracy of the experiments of Chauveau, examined 
those particles microscopically, and found them to be identical with the Torula form of 
the Micrococcus , viz. small spheroids joining so as to form necklace-like chains. According 
to Sanderson, these spheroids (microzymes) tend to elongate into rod-like bodies endowed 
with a peculiar progressive or oscillatory movement, generally regarded as belonging to 
Bacteria (Twelfth Report of the Medical Officer of the Privy Council, 1869, p. 229). 
Cohn found that when lymph is collected from a pustule with the utmost care, it can 
be kept free from Bacteria or spores of fungi for an indefinite period. Cohn’s method 
is as follows: — A perfectly clean lancet is used for the opening of the pustule ; the drop 
of lymph which escapes from the aperture is drawn into a capillary tube, and then 
brought on a glass slide previously cleaned with ammonia, and covered with a covering- 
glass cleaned in the same manner, care being taken that there are no air-bubbles either 
in the middle or at the edges of the preparation. The edges of the covering-glass are 
then fixed by means of asphalt varnish, and the preparation can now be examined either 
fresh or after exposing it in an incubator to a constant temperature of 35° C. 
In this way Cohn found that the lymph remains barren of Bacteria and any other 
germs of mould. Such clear lymph could also be used for inoculating, after Dr. Sander- 
son’s method, boiled Pasteur’s fluid without producing Bacteria or other vegetable 
fungi, even when it was kept exposed to a temperature of 30 to 40° C., whereas after 
the least contamination the fluid soon became turbid and decomposed. In the perfectly 
fresh lymph, Cohn describes, in accordance with Dr. Sanderson, pale spheroids of an 
extremely small size, below 0 1 001 of a millim. ; they have no peculiar movement; they 
are, immediately after the preparation is made, generally isolated, occasionally in couples, 
like a dumb-bell. 
In a very short time, however, the dumb-bells increase in number, and form curved 
or zigzag chains of four members. After one to two hours there are already numerous 
necklaces of eight members, or the members arrange themselves like Sarcina, or they 
form, by simple juxtaposition, groups or colonies. 
The spheres proliferate very quickly by transverse division ; so that after six or eight 
hours there are, besides chains of two to four and eight members, also very numerous 
colonies of sixteen to thirty-two or more members to be found all over the preparation. 
The proliferation continues during several days ; the colonies enlarge and reach even 
the size of ten micromillimetres. 
A colony or zoogloea represents a group of spheres held together by an intervening 
gelatinous transparent substance. Cohn calls these organisms Micros'phaera vaccince , and 
places them amongst the family of Schizomycetes in the group of Bacteriaceas (Virchow’s 
‘ Archiv,’ vol. lv. p. 234). In the second volume of 4 Beitrage zur Biologie der Pflanzen,’ 
in his well known “ Untersuchungen fiber Bacterien,” p. 161, Cohn calls them Micrococci 
MDCCCLXXV. 2 H 
