SHAPE OF MICROORGANISMS 33 



to grow, it is again heated for a short time, thus killing the others 

 which have started to grow. Often this is repeated even a third 

 time before the vegetable or other product is canned. 



The manner of formation bf the spore within the body of the 

 organism is intensely interesting, for it varies with different spe- 

 cies. The bacteriologist has devised means whereby he can color 

 the body of the organism one color and the spore within the 

 body a diiferent color. If we stain the various organisms in the 

 first stages of spore formation, in some we find the little red dot 

 situated within the center of the blue body. In others it is also 

 in the center, but is much wider than the body of the organism. 

 Hence, we have a boat-shaped organism, Clostridium. In others 

 the spore forms at the end, and we have the drumstick-appearing 

 organism, the capitate. This is the case with the organism causing 

 lockjaw. 



Longevity of Bacteria. — Due to their method of multiplica- 

 tion there is no such condition as old age among bacteria since 

 both daughter cells are similar in age and composition. _ It is well 

 known that while in the spore condition many bacteria can sur- 

 vive for a quarter of a century. They have been obtained from 

 soil which has been kept under air-dry conditions in fruit jars 

 for over fifty years. There is evidence they may live for 

 centuries. 



Morphology of Yeast. — ^Yeasts vary in form from a sphere 

 to an ellipsoid. They are surrounded with quite a thick mem- 

 brane in which is a colorless liquid containing vacuoles and gran- 

 ules. On staining they are found to possess a definitely organized 

 nucleus. Most yeasts are considerably larger than the bacteria. 

 Their characteristic method of multiplication is by budding. The 

 bud appears as a small protuberance separated from the mother 

 cell by a very narrow collar. The bud increases in size, and 

 when it has acquired a certain size it separates from the mother 

 cell. The daughter cell grows and soon equals that of the mother 

 cell, after which it in turn buds. When multiplication is very 

 active each cell may form many buds at the same time on differ- 

 ent parts of its surface. It may happen that the buds while at- 



