20 SPONTANEOUS GENERATION. 



twenty-ninth, and the flask was opened on the thirty-ninth 

 day. The solution was found to contain Bacteriums, and cells 

 filled with them. In xxx. the film was formed on the seventh 

 day, and Bacteriums were found on the twenty-third, when there 

 was a slight odor of putrefaction. 



" Expts. xxxi., xxxii., xxxiii. (B.) March 24th. 30 grains of 

 sugar, 20 c. c. of beef-juice, 158 c. c. of water, were divided into 

 three parts, and each part put into a flask of 550 c. c. capacity, 

 and boiled 15'. No film was formed in either of them, xxxiii. 

 was opened on the thirtieth day ; ferment cells (fig. 7) and some 



Fig. 7. Torula Cerevi- 

 sice. Yeast -plant. Mag. 

 500 diam. Original. From 

 new yeast. In all fluid 

 fermentations, in yeast, and 

 among decomposing fluid 

 matter, what are called 



Tig~7" " ferment-cells " are found 



in greater or less abundance. It is in such conditions that this lowly organized 

 member of the vegetable kingdom finds its proper basis for origin and develop- 

 ment. Where it is abundant one may have all stages of growth represented at 

 one time in the field of the microscope, as they are illustrated from a to /, in 

 this cut ; and by watching for a few hours the whole process of cell multiplica- 

 tion from a to ./may be seen. The little spherical granulated cell at a is about 

 40 1 00 of an inch in diameter ; but it was originally much smaller, for it may be 

 traced from excessively transparent globular bodies, with soft, delicate outlines, 

 not more than T0 o o of an inch in diameter. As it progresses in development, 

 one side of the cell bulges out, as at b ; and this bulging grows until another cell 

 is formed like the one at c; then the first cell, increasing in size, (d,) develops 

 another cell-like body, (rf 1 ,) called the nucleus, in its fluid contents, whilst the 

 second cell sends out a bulging process, which eventually becomes a third cell. 

 In this way a single string of cells is formed ; but quite as frequently the primary 

 cell develops a new cell from two different points, as at e ; or even three cells 

 are developed from the primary one, (see the largest cell at /",) and, each of 

 these secondary cells developing a cell from its sides, produce together the irreg- 

 ular branching form, which we have here represented as the perfect " yeast- 

 plant " (/) It is well known now, however, that this is not its perfect state. 

 Under favorable circumstances, the yeast-plant, so-called, rises to the surface of 

 the fermenting fluid, and clinging to the side of the vessel, allows its growing 



