838 RECORD OF CURRENT RESEARCHES RELATING TO 



most alterable liquors. In the interior of houses, in the absence of 

 mechanical movements raising dust from the surface of objects, the 

 air is fertilizing only in a volume of 30 to 50 litres. In M. Miquel's 

 laboratory, the dust of 5 litres usually serves to effect the alteration 

 of neutral bouillon. In the Paris sewers, infection of the same liquor 

 is produced by particles in 1 litre of air. 



These results differ considerably, it is pointed out, from those 

 published by Tyndall, who says that a few cubic centimetres of air 

 will, in most cases, produce infection in the most diverse infusions. 



M. Miquel compared the number of deaths from contagious and 

 epidemic diseases in Paris with the number of bacteria in the air 

 dui'ing the period from December 1879 to June 1880, and established 

 that each recrudescence of aerial bacteria icas followed at about eiglit 

 days' interval by an increase of the deaths in question. Unwilling to 

 say positively that this is more than a mere coincidence, he projects 

 further observations regarding it. 



Bf . Miquel further finds (contrary to some authors) that the water- 

 vapour which rises from the ground, from rivers, and from masses in 

 full putrefaction, is always micrographically pure ; that gases from 

 buried matter in course of decomposition are always exempt from 

 bacteria : and that even impure air sent through putrefied meat, far 

 from being charged with microbia, is entirely purified, provided only 

 the putrid filter be in a state of moisture comparable to that of the 

 earth at • 3 metre from the surface of the ground. 



Modification of the Properties of Bacillus anthracis by Culti- 

 vation.* — In the course of some experimental investigations into the 

 pathology of anthrax at the Brown Institution, made during the past 

 twelve months, two series of phenomena have been the subject of 

 study, and in each some results have been attained which Professor 

 W. S. Greenfield (in a " preliminary note ") believes to be novel, and 

 of considerable practical importance if verified by other observers. 



The practical purpose of these investigations was to ascertain 

 (1) by what means the virus of splenic fever may be so modified as 

 to be capable of inoculation without fatal result, and (2) whether a 

 modified attack, produced by inoculation, exerts any protective 

 influence against a futm*e inoculation with unmodified virus. 



The conclusions arrived at by these experiments were as follows : — 



1. That anthrax may be artificially communicated to bovine 

 animals by inoculation with the blood or spleen of the guinea-pig 

 which has died of the disease artificially induced, and that the same 

 result may be attained by inoculation with the Bacillus anthracis 

 cultivated from the fluids of a rodent ; the disease thus induced being 

 severe, but rarely fatal to previously healthy bovine animals, a result 

 previously attained by Dr. Burdon-Sanderson independently. 



2. In all the cases thus inoculated, the animals appeared to have 

 acquired either a considerable degree of protection or entire immunity 

 from the results of subsequent inoculation, although much larger 

 doses of the virus were employed. 



* ' Proc. Eoy. Soc.,' xxx. (1880) p. 557. 



