Report on the Bacteriology of Water. 287 



off. The ripe spore does not contain all the cell-contents, but lies 

 embedded in a matrix of something remaining over from the cell- 

 protoplasm. This might also be inferred from the double staining 

 of which such preparations are capable. 



In this case, therefore, the whole life-history from spore to spore 

 was gone through in a little over forty hours. 



Another equally interesting and rapid case of spore-formation is 

 figured in fig. 19, where the changes in the granules and the gradual 

 isolation of the spore mother-cells are again evident traced under a 

 still higher power (l/20th oil immersion). 



In fig. 20 I have shown a series in a case which presents some 

 points of extreme interest, which, it seems to me, would be well worth 

 special study. 



A culture which had been exposed to blue light, and was much 

 retarded, began to show signs of spore-formation at 2 P.M. the 

 filaments being then sixty-four hours from sowing. It was now in 

 ordinary daylight, but I have no records of the details of tempera- 

 ture. 



The peculiarities observable are (1) the very late appearance of the 

 bright granules; (2) that they were first developed in cells much 

 longer than usual ; (3) their slow changes of position during 

 several hours (fig. 20 a c) ; (4) the subsequent division of the 

 cells to the short form characteristic of spore-mother-cells (fig. 20 

 c, d) ; and (5) the incomplete character of the spores when they 

 did at last appear more definitely in some of the cells. 



I cannot avoid the conclusion that the blue light had something 

 to do with this retardation and hindrance of spore-formation an 

 observation quite in accordance with some earlier ones on the 

 development of spores in fungi* and, as said, believe the subject 

 well worth further study. 



That the bodies above described are true spores is proved by their 

 behaviour towards staining and other reagents, their resistance to 

 high temperatures.f and above all by their germination which, as we 

 have seen, I have observed and traced stage by stage. 



They refuse to stain by all the ordinary methods for staining the 

 bacilli, but stand out from the coloured protoplasm in such cases 

 like brilliant colourless oil drops ; on the other hand they stain fairly 

 easily by the usual methods for spores, and especially with aniline- 

 fuchsin or anilin-methyl violet, after being passed 10 times through 

 the flame. 



The ripe spores from potato- or agar-cultures germinated readily 



* See 'Hot. Zeitung,' 1885, p. 6, where L. Klein confirms Rindfleisch in the 

 observation that the development of the conidia of Sotrutis is inhibited by blue 

 liglit and by ordinary daylight, but not by red light. 



t See pp. 350 and 351 for more detailed proofs of this. 



