136 RECORD OF CURRENT RESEARCHES RELATING TO 



Cause of the Movements of Bacteria.* — Some of the bacteria, such 

 as most species of Micrococcus, Bacillus anthracis, &c., are known only 

 in a stationary condition ; other allied species, as Bacterium Termo and 

 Spirillum volutans, are ordinarily in a condition of movement ; while 

 others, e. g. Bacillus Amylohacter, are known in both conditions. The 

 cause of all organic movements is no doubt ultimately the contractility 

 of protoplasm. But this may take two forms. The contractility may 

 reside in the protoplasm, which is entirely enclosed within a cell-wall, 

 although this cell-wall may be prolonged in places to filiform structures, 

 to which the term appendages may be given. Or, secondly, a portion of 

 the protoplasm may protrude through the cell-wall in the form of fine 

 threads or vibratile cilia. To which of these modes the bacteria owe 

 their power of movement has been a subject of controversy ; and Van 

 Tieghem believes he has now established that it is always the former, 

 and that the supposed vibratile cilia alleged to have been detected by 

 some observers were really appendages invested with a cell-wall. 

 His observations were made chiefly on B. Amylohacter ; neither iodine 

 nor any of the aniline pigments produced on the appendages the 

 characteristic colouring of protoplasm. This is considered by Van 

 Tieghem to re-establish the affinity held by Cohn to exist between 

 the bacteria and the Phycochromacete. 



Action of Dry Heat and of Sulphurous Acid on the Bacteria 

 which accompany Putrefaction. f — A. Wernich has carried out a 

 series of experiments on the influence of these disinfecting agents on 

 the production of bacteria in Pasteur-'s solution, in which were dipped 

 pieces of cotton-wool, wadding, and linen which had been steeped in 

 putrefying flesh liquid, and then slowly dried. Exposure to a tempe- 

 rature of 140^-150° C for a period of from one to two minutes delayed 

 the bacteria-turbidity two to three days, while it commenced in 

 twenty-four hours after the substance had been exposed 10-60 minutes 

 to a temperature of 110°-118° C. Exposure to 125°-150^ C. for five 

 minutes prevented all bacteria-infection, even for a period of eleven 

 days. 



When volume-percentages of 1 • 5, 2 • 2, and 3 • 3 of sulphurous acid 

 were produced in a glass vessel, to which the materials were exposed, 

 even if continued for twenty-two hours, no effect ensued on the produc- 

 tion of the bacteria- turbidity in the solution. When exposed to 4, 6 • 6 

 or 7-15 per cent, (in volume) of sulphurous acid for six hours, the 

 production of bacteria was entirely prevented ; but this was not the case 

 when the exposure lasted only twenty, forty, sixty, or two hundred 

 minutes. The different substances named were freed with different 

 degrees of facility from the infection-germs ; eotton-wool the easiest, 

 linen next, and wadding with the most difficulty. 



Microscopic Mycological Preparations. J — A series of myco- 

 logical preparations for the Microscope by Dr. O. E. E. Zimmermann, of 

 Chemnitz, in Saxony, is described by von Thiimen as being of great 

 value as an aid to instruction in mycology. The preparations are 



* 'Biill. Soc. Bot. France,' xsvi. (1879) p. 37. 



t ' Oentralblatt med. Wiss.,' xvii. p. 227; see ' Naturforscher,' xii. (1879) p. 311. 



j 'Oesterr. Bot Zeitschr.,' xxix. (1879) p. 330. 



