238 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
against diphtheria or tetanus possesses the extraordinary power of de- 
stroying the poison caused by the microbe of this disease. As this 
power is also possessed by the serum of such an immune animal, the 
serum can be used as a curative means on other animals that are suf- 
fering from the disease. 
After reviewing the work lately done by various investigators into 
immunity, Mr. Hankin tells us that the essential new proposition is this : — 
“ The immunity of rabbits and mice against tetanus depends on the power 
possessed by the fluid part of their blood of rendering harmless the 
poisonous substances produced by the tetanus bacilli.” This is a com- 
pletely new theory of the nature of immunity ; for, hitherto, it has been 
supposed that immunity must depend either on the voracious activity of 
the phagocytes, or on a bacteria-killing power possessed by the blood, 
or on an acquired tolerance against the poison. 
The authors’ experiments show that the blood of rabbits which have 
been made immune against tetanus can destroy the tetanus poison ; this 
character is possessed by the blood both before and after it has left the 
vessels, and by the cell-free blood-serum obtained from it. This cha- 
racter is so permanent that it is still manifested by such serum after it 
has been injected into other animals. Various experiments are described 
which supjDort these statements. 
Bacillus developing a Green Pigment.* — Herren F. Winkler and 
H. von Schrotter isolated from the excrement of the caterpillar infesting 
an apple (Carpocapsa pomonella L.) a bacillus from 2-2*5 p long, easily 
stainable with anilin dyes, and which, when cultivated on gelatin plates, 
liquefies the medium, causing the development of a greenish-yellow 
colour and a peculiar smell. In test-tube cultivations these character- 
istics are more pronounced, especially the liquefaction and the pigment 
production. 
The pigment is very soluble in water, but insoluble in alcohol and 
chloroform. It is destroyed by acid, and restored by the application of 
alkalies. When cultivated on plover’s-egg albumen, it developes with 
the production of a fine emerald green colour, while the liquefaction is 
delayed. On potato there was formed a reddish-yellow greasy-looking 
overlay, the result of confluence of the colonies. 
The pathogenic effect of this bacillus was tried on rabbits, some 
being injected in the vena jugularis externa and others in the peritoneal 
sac. The former were unaffected, while the latter succumbed from 
peritonitis and gangrene of the intestine. 
The authors propose to call this micro-organism Bacillus melochloros. 
Bacillus producing an Indigo-blue Pigment.| — Herr H. Claessen 
found in Spree water a chromogenous micro-organism, the rod- elements 
of which corresponded approximately in length and breadth with those 
of B. typh. abdominalis. These rodlets were usually separate, but 
sometimes two or three were found together, and occasionally groups 
united by a cement. The outline of the rodlets was clearer than the 
centre of the bacilli, which by staining showed that they were enveloped 
* Mittheil. aus d. Embryol. Institute d. K. K. Universitat Wien, 1890, pp. 60-5. 
f Centralbl. f. Bakteriol. u. Parasitenk., vii. (1890) pp. 13-17. Of. Bot. 
Centralbl., xlii. (1890) p. 146. 
