170 THE MICROSCOPICAL NEWS. 
B. Grove, B.A., Hon. Sec., Birmingham Nat. Hist. and Micros. 
Soc., and accompanied by typical illustrations. An excellent 
systematic account of the family will be found in Dr. A. Magnin’s 
“‘ Bacteria,” translated by Dr. Sternberg, (Boston, U.S. A.), illus- 
trated by photo-micrographs. 
Since Pasteur’s discovery of the “ attenuated virus ” of anthrax, 
it has been an interesting problem whether, and under what con- 
ditions, an innocuous saprophyte can become a noxious parasite ; 
whether, for instance, the active and harmless Baczllus subtilis, of 
hay infusions, may be converted, by change of “soil,” into the 
motionless and deadly B. anthracis of splenic fever ; and if so, 
whether the converse proposition may not also be true, viz. : that 
the noxious parasite may become changed into the innocuous 
saprophyte. In other words, is the parasite a “sport” from the 
saprophyte? Prof. von Nageli and his pupil, Dr. Hans Buchner, 
have undertaken this investigation, and believe that they have con- 
firmed the truth of this theory. The latter states that he has not 
only converted the Bacillus of anthrax into another, morphologi- 
cally identical with the Bacillus of hay infusion, but that he has 
also transformed the latter into the dangerous pathogenic parasite 
of anthrax. Dr. Klein, who has also carried out a series of similar 
investigations, does not regard this as proved. ‘The importance of 
this question can scarcely be over-estimated, because if the patho- 
genic species are sports from the harmless ones, a knowledge of the 
conditions of life upon which such a change is dependent may be 
the means of preventing some virulent contagious diseases. The 
consideration of this question I must reserve for another occasion. 
( Zo be continued, ) 
MOUNTING OBJECTS IN PHOSPHORUS. 
N a paper read before the Royal Microscopical Society on the 
tith of January of last year, Mr. J. W. Stephenson gave the 
details of this method of mounting, and stated that the slides, 
prepared “nine years ago, and exhibited on the 4th June, 1873,” 
still remain unchanged. 
There are four points of importance :— 
1. The object must be absolutely dry. 
2. The phosphorus must be introduced with the least possible 
exposure to the air. 
3. The solution of phosphorus must be clean and bright, and 
4. The operator should have both water and oil (olive) at hand 
