SPONTANEOUS GENERATION. 19 



xvi. was boiled 15', the film formed on the second day and the 

 flask was opened on the ninth. Vibrios were found in abun- 

 dance, (fig. 5, 6,) of different lengths, some of them moving with 

 great rapidity, xvii. was boiled 30', the film was formed on the 

 third, and the flask was opened on the ninth day. Vibrios were 

 found in great numbers, some of them bending and extending 

 themselves rapidly. Some minute spherical bodies were also 

 seen, having the kind of motion which results from vibrating 

 cilia, though none of these were detected, xviii. was boiled 15', 

 the fluid having been previously filtered ; the film formed on the 

 third, and the flask was opened on the eighth day : the organ- 

 isms found were the same as in xvii. xix. was boiled one hour. 

 The film formed on the second, and the flask was opened on the 

 twenty-fourth day. The infusion had a slightly putrid odor, 

 and contained Vibrios and Bacteriums. 



" Expts. xxix., xxx. (A.) February 17th. In both of these the 

 contents of the flasks were solutions of sugar and gelatine in 

 water, to which fragments of cabbage-leaves were added. The 

 air was introduced through a Bohemian glass tube, filled with 

 asbestos and platinum sponge, and heated to redness. The ma- 

 terials were boiled 30'. In xxix. the film was formed on the 



Fig. 6. Bacterium (Zooglcea) lermo. a, a group mag- 

 nified 500 diameters ; b, c, d, magnified 3500 diam. When 

 seen as at a, they appear like minute, oval, brilliantly 

 refracting granules, dancing in a constant zigzag, some- 

 thing like a swarm of mosquitoes vibrating in a sunbeam. 

 They never move in a direct course, but ever hover about 

 the same spot ; in this respect imitating the spores or 

 seeds of certain aquatic plants. By the application of a 

 higher power of the microscope we may recognize their shape more distinctly. 

 Most frequently they were found, as at b, simple guitar-shaped bodies with a 

 dark oval centre, and excessively transparent ends ; but now and then one or 

 two of them were enclosed in an exceedingly transparent envelope, as at c and 

 d, which appeared like a halo around them. In this condition they resembled 

 some of the jointed Vibrios. The transparent gelatinous envelope is eminently 

 characteristic of certain kinds of mould, growing in damp places. Original. 

 (See fig. 8.) 



