THE AMERICAN MONTHLY 



[January, 



tube can be thoroughly cleaned and 

 safely used an indefinite number of 

 times. 



' The points about the tube which 

 make the 

 above -men- 

 tioned r e - 

 suits attain- 

 able are : — 



'I. The 

 whole ap- 

 paratus, in- 

 cluding the 

 filter, con- 

 sists of glass 

 which can 

 be heated to 

 a high tem- 

 perature 

 without in- 



' 2. The 

 ventilating 

 tube allows 

 escape of 

 steam when 

 heating, and 

 thus p r e- 

 vents explo- 

 sion from 

 pressure; al- 

 so an equal- 

 i zati on of 

 pressure 

 within and 

 without at 

 all times, so 

 that there is 

 no rushing 

 in of u n - 

 ste r i 1 i z e d 

 air when 

 the tube is 

 opened. 



'3. The 

 large ground 

 joint perm its 

 filling and 

 thorough 

 cleaning without trouble. The small 

 joint is necessary to prevent exposure 

 of a large opening, which would 

 greatly increase chances of contami- 

 nation when infecting or examining. 



mmm 

 Wmm 



ill 



i ii; 



# 



Fig. 2. — Salmon's Culture Tube. 



' 4. The glass-wool filter can be 

 dried at a high temperature imme- 

 diately after the liquid is sterilized. 

 This is necessary to safety, as some 

 moisture will condense in the filter 

 during sterilization, and must be 

 quickly evaporated by heating the 

 ventilating tube in the flame of a 

 lamp. 



' Before inventing this tube I used 

 one made on a similar principle. It 

 consisted of a test-tube and rubber 

 cock, through which passed a glass 

 tube which was attached to the ven- 

 tilating tube by caoutchouc tubing. 

 The filter was then of cotton wool. 

 They could be used safely with care, 

 but were not quite as convenient as 

 the new style, nor could they be 

 heated to so high a temperature. 

 They were sterilized by intermittent 

 boiling, which required at least two 

 days' time instead of an hour as at 

 present.' 



The Life History of Vaucheria.* 



BY A. H. BRECKENFELD. 



Nearly a century ago, Vaucher, the 

 celebrated Genevan botanist, describ- 

 ed a fresh water filamentus alga, 

 which he named Ectosper777a gemi- 

 nata, with a correctness that appears 

 truly remarkable when the imperfect 

 means of observation at his command 

 are taken into consideration. His 

 pupil, De Candolle, who afterwards 

 became so eminent a worker in the 

 same field, when preparing his ' Floi'a 

 of France,' in 1805, proposed the 

 name of Vaticheria for the genus, in 

 commemoration of the meritorious 

 work of its first investigator. On 

 March 12th, 1826, Unger made the 

 first recorded observation of the for- 

 mation and liberation of the terminal 

 or non-sexual spores of this plant. 

 Hassall, the able English botanist, 

 made it the subject of extended study 

 while preparing his fine work entitled 

 'A History of the British Fresh Water 

 Algae,' published in 1845. He has 



* Read before the San Francisco Microscopical So- 

 ciety. 



