214 CALIFORNIA ACADEMY OF SCIENCES. [Proc. .^d Ser. 



but had not branched in the agar-agar and very few if any 

 more spores had germinated, whereas in the water culture 

 the tubes were longer, some of them had branched, as fig. 3 

 shows, and the number of spores germinated had increased 

 considerably. In eight days more, that is, in eighteen days 

 after the spores were collected on the cover-glasses, growth 

 had ceased in all the cultures. The differences between 

 the water cultures on the one hand, and the agar and gela- 

 tine cultures on the other, were now still more evident. 

 The germinated and ungerminated spores in the water cul- 

 tures still looked healthy, and the number of bacteria in the 

 cultures was comparatively small. In the other cultures, 

 however, there were many spores evidently dead, the 

 remainder looked unhealthy, the germinated ones least so, 

 and the number of bacteria flourishing on and in the agar- 

 agar and the gelatine was sufficiently large to justify the 

 inference that they were an important if not the sole cause 

 of the unsatisfactory condition of the spores. 



The contents of the spores which appeared to be alive at 

 all were far less highly refractive than at first; perhaps, but 

 not wholly, because of the consumption of the oil which 

 was stored in them in the form of drops of very consider- 

 able size (figs. I a and b, 2, 3 and 4). The death of the 

 spores was marked by certain changes in the cell contents: 

 the protoplasm lost its granular character and gradually 

 became indistinguishable from the wall and the cell-sap, 

 the oil drops spread, became confluent with one another, 

 later appeared to fill the whole cavity of the cell, and finally 

 disappeared altogether, leaving only the empty cell-wall. ► 

 Minutely to follow the disorganization-phenomena (" Dis- 

 organizationserscheinungen ") is very difficult, owing to the 

 small size of these two-celled spores. 



From what I have noticed, I can only suspect, not con- 

 clude, that the spores were killed and disorganized by the 

 products of the discouragingly active bacteria. That the 

 same appearances may be produced in another way is 

 shown by a water culture made as above described, but 

 with the hollow below the cover-glass filled with sterilized 



