PERSISTENCE OE PUTREFACTIVE AND INFECTIVE ORGANISMS. 
191 
then introduced into boiled test-solution contained in a superheated glass. On February 
6th the liquid was already milky, and teemed with Bacteria. 
“ To determine the effect of more complete desiccation, an eprouvette containing one 
cubic centimeter of cold water, previously ascertained to be zymotic, was evaporated to 
dryness in the incubator, and kept for some days at a temperature of 40° Cent. On 
February 20th the dried glass was charged with boiled and cooled solution, and plugged 
with cotton-wool in the usual way. The liquid was examined microscopically on March 
2nd, when it contained numerous Torula- cells, but no trace of Bacteria. It therefore 
appears that the germinal particles of Bacteria are rendered inactive by drying without 
the application of heat. 
“As it appeared probable,” continues Dr. Sanderson, “ that in the previous experi- 
ments with Bacteria- scum desiccation might be prevented by the gelatinous matrix, a 
portion of the same scum was thoroughly washed with water, collected in the eprouvette, 
and dried for some days in the incubator. The eprouvette was then charged with both 
boiled and cooled Pasteur’s solution, and plugged with cotton-wool. On March 11th 
the liquid was slightly hazy, but was found to contain no trace of Bacteria. The hazi- 
ness was due to the presence of Torula-ceWs in great numbers. It thus appeared that 
fully-formed Bacteria are deprived of their power of further development by thorough 
desiccation.” 
To the present hour these experiments are quoted as conclusive in reference to the 
influence of desiccation. They are quoted, moreover, as applicable not only to the deve- 
loped Bacterium , but also, without restriction, to the germs from which Bacteria spring. 
“To maintain,” says Dr. Bastian *, “ his Panspermism in the face of his own experi- 
ments, Spallanzani was compelled to assume that the germs of the lower infusoria do 
possess this seed-like property of developing after desiccation. Modern science, how- 
ever, declares that they have no such property. We are told most unreservedly by 
Professor Burdon Sanderson, not only that the germinal particles of Bacteria are 
rendered inactive by thorough drying, without the application of heat, i. e. by mere 
exposure to air for two or three days at a temperature of 104° Fahr., but also that fully 
formed Bacteria are deprived of their power of further development by thorough desic- 
cation.” In this unqualified sense the conclusion is certainly an erroneous one ; and that 
it is so has been proved by experiments far more stringent than those of Dr. Sanderson. 
I could cite a multitude of such experiments, but a reference to one or two of them will 
here suffice. 
A small bunch of old Heathfield hay was washed with distilled water, which was 
received into a champagne-glass. The glass was placed on a stove until the water had 
all evaporated, and the dried residue was permitted to remain upon the stove for several 
days. Dr. Sanderson’s drying temperature was 104° Fahr., mine was 120° Fahr., and 
my period of drying was longer than his. Scraping a little of the dry sediment treated 
as above from the bottom of the champagne-glass, I infected with it a bulb containing 
* ‘ Evolution/ p. 156. 
2 E 2 
