470 SUMMARY OF CURRENT RESEARCHES RELATING TO 



wards, at a second puncture, has more or less coagulability, and possesses 

 an appreciable amount of complement. They found that the opsonic 

 power increased proportionately with the bacteriolytic complement. 

 The fluid of oedema produced by ligaturing a rabbit's ear is free from 

 complement if free from blood, showing that the complement does not 

 exist free in the circulating plasma. The polymorphonuclear blood- 

 cells elaborate the bacteriolytic complement, but extracts of these 

 leucocytes have no opsonic properties. 



The normal opsonin is identical with the complement ; as this 

 complement does not circulate in the plasma, it luust be assumed that 

 its opsonic properties do not play an important part in the defensive 

 processes of natural immunity. 



The opsonic properties of specific serums obtained from animals 

 vaccinated against pathogenic bacteria, differ from those of normal 

 serums in being thermostable ; and whereas when B. typhosus, 

 staphylococcus, or B. dysenterke. are placed in contact with a normal 

 fresh serum, the microbe absorbs not only the opsonin that acts on this 

 microbe, but also those that influence the other two ; if the experiment 

 is repeated with a specific serum (anti-typhoid serum), the opsonin is 

 only taken up by the microbe which has served for the specific 

 immunisation {B. typJiosus). 



The authors consider that the opsonins of specific serums have a 

 complex constitution analogous to that of bacteriolysins and hemolysins, 

 and are allied to amboceptors. 



The opsonising serums only exaggerate more or less the phagocytosis 

 that can occur, although slowly, without their intervention. 



Human leucocytes are more sensitive to the action of opsonins than 

 the leucocytes of the rabbit or guinea-pig. The phagocytosis and 

 sensitiveness to opsonins of a microbe increase with the age of the 

 culture. Opsonins produce a physico-chemical alteration in the 

 microbial envelope, so rendering the organism more able to be 

 phagocytosed ; this alteration is analogous to that which precedes 

 agglutination, and is independent of the vitality of the bacteria. 



Bacillus faBcalis alcaligenes.* — W. N. Klimenko finds that the 

 B.fcecalis alcaliyenes is closely related to B./liwrescens nonUquef miens ; 

 it differs from B. typhosus in having flagella only at the ends of the 

 rod, whereas B. typhosus is peritrichous, and in the production of alkali 

 on Petruschky's medium, and on medium containing mannite, whereas 

 B. typhosus produces acid under similar conditions. 



New Species of Thread Bacteria.f — D. Ellis describes a new thread 

 bacterium, to which he has given the name of Spirophyllum ferrugineum. 

 The body of the cell is elongated, flattened, and spirally twisted ; the 

 width varies from 1-6 /x. and the length may be 200 /a or more ; the 

 edge of the cell is thickened, and the ends are irregular ; the majority 

 have a spiral length 3-4 times greater than the width. The organism 

 has only been found in iron-water, and, excepting the youngest stages, 

 is coated with a thick deposit of ferric hydroxide. It multiplies by the 



* Centralbl. Bakt., Ite Abt. Orig., xliii. (1907) p. 755. 

 t Proc. Roy. Soc. Edinburgh, xxvii. (1906-7) p. 21. 



