352 
NOTES AND MEMORANDA. 
ordinary atmosphere, and being extremely small and light, that after 
they are dry they will float about along with other solid particles in 
disturbed, and settle down in quiet atmospheres without undergoing 
any change until they find themselves in a medium which admits of 
their growth and development. In all probability, desiccation de- 
stroys the oval and dumbbell-shaped forms of Micrococcus, the round 
spore-like forms only retaining their vitality. . . . 
Along with Dr. Burdon Sanderson,* I have shown that the 
spores of B. anthracis are destroyed when the fluid they are suspended 
in is kept for a few minutes at the point of ebullition. The same is 
true of B. termo and Micrococcus. On the other hand, when they are 
subjected to a temperature of 110° C. in a dry state, they are not 
destroyed ; they are rendered inactive, however, by a temperature of 
120° C. The difference between the effects of moist and dry heat is 
probably owing to the gelatinous capsules of the spores and Micro- 
cocci giving way, and thus allowing the boiling fluid to come into 
direct contact with the unprotected central protoplasm.” j* 
Life- History of Spirillum. — Dr. Ewart in conjunction with Mr. 
Patrick Geddes also contributes a paper on Spirillum. They point 
out that, notwithstanding the numerous and fruitful researches which 
have been recently made into the life-history of Bacteria, our know- 
ledge of the common and interesting curved and spiral forms — the 
Vibrio and Spirillum of Ehrenberg — has made little or no advance 
since his time, neither embryonic nor reproductive forms having ever 
been observed ; while even the zoogloea phase, so characteristic of 
Bacterium and Bacillus, has only been once mentioned,^ and then in 
a different form. (The authors add in a note that they are very 
strongly of the oj^inion that the forms described by various authors 
as Vibrio are merely either (1) zigzag dividing Bacillus, (2) slightly 
waved Bacillus, or (3) undeveloped Spirillum, and hence that Vibrio 
should no longer be used as a generic term.) 
The life-history of Spirillum, so far as at present known, is thus 
summarized. The well-known motile corkscrew may alternate between 
the active and resting states, and ultimately lengthen out into a small 
filament, which loses its definite twist and may freely bend or 
straighten. This thread grows into a much larger and longer 
motionless filament, in which spores appear. These rapidly divide 
and acquire a bright brown colour, the filament reassuming the 
motile condition, and sooner or later breaking up. The freed spores 
encyst and divide, forming capsules, which after a period of quiescence 
themselves become motile, the sporules contained in them escape and 
germinate into ‘‘ commas,” which become Vibrio-like, and soon grow 
into the common motile Spirillum. 
The resemblance of all this to the life-history of Bacterium termo 
and Bacillus described in the preceding paper is at once apparent. 
Not only is there the same alternation of a resting with a motile 
phase, but there is a lengthening into filaments, the protoplasm of 
* ‘ Quart. Jour. Micro. Science,’ April, 1878. 
+ ‘ Proc. Roy. Soc.,’ voL xxvii. p. 474. 
t Lankester, ‘ Quart. Jour. Micro. Sci.,’ vol. xiii. p. 424. 
