INVERTEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 999 



cetes, especially to the albumen-bacteria. The luitrient fluid employed 

 was hard-boiled white of egg pounded in a mortar and then boiled 

 for an hour. The milky fluid thus obtained was preserved free from 

 bacteria for weeks by a carbol-wad. In order to obtain the bacteria, 

 he allowed a small, clean, strongly-heated glass, into which a small 

 quantity of the fluid had been poured, to stand exposed. In the 

 space of twenty-four houi's, numerous rods had made their appearance 

 in it ; the sulphuretted hydrogen reaction set up from five to eight 

 days later. The progressive development of the bacteria was 

 observed partly in the decoction of albumen placed in a hatching- 

 oven, partly in solutions of albumen infected with fresh bacteria, and 

 protected by a wad-stopper, also placed in the hatching-oven. 



On the first day there were seen only small motile spherules and 

 rods ; on the following days the rods had increased in size, the 

 spherules had disappeared. The rods were partly free and motile, 

 partly collected into zoogkea-colonies. The sulphuretted hydrogen 

 reaction began with the formation of zoogloea, increased for five or 

 ten days, and tlien again decreased. As this evolution increased, the 

 zooglosa-colonies again always dispersed, and the rods gradually 

 disappeared, breaking up into strongly refractive spherules. When 

 the evolution had ceased, the spherules often again grew into rods, and 

 the development began afresh. There was a difference in the result 

 according as fresh albumen-bacteria or bacteria from a solution in 

 which sulphuretted hydrogen had already begun to be produced, were 

 placed in the albumen-decoction. In the latter case the sulphuretted 

 hydrogen reaction was manifested on the second day, in the former 

 generally not till the fifth. In two cultures, bacteria from a fresh 

 solution containing no suli>huretted hydrogen, and secondly from one 

 in which the gas was being abundantly developed, and in which there 

 were already a niimber of rods, were sown in boiled and unboiled 

 milk, in boiled urine, and in a decoction of ergot. 



It was now seen that the stage of development of the bacteria 

 influenced the process of decomposition in the new nutrient fluid. 

 The young bacteria merely turned the milk sour or somewhat 

 accelerated the acidity ; the more vigorous old bacteria, which had 

 already caused a production of sulphuretted hydrogen in the albumen- 

 solntion, produced the same reaction in the fluid ; they continued to 

 develop, while tlie young bacteria were more indiflerent, or altogether 

 perished. In fresh milk no eficct was produced ; the natural ferment 

 acted quicker and more strongly. In urine the older bacteria always 

 produced alkalinity more rapidly than the younger ones ; in ergot- 

 decoction both soon perished. Ho also introduced the bacteria from 

 putrefying blood, tobacco- and pea-decoction into a great variety of 

 nutrient fluids. 



The general results arrived at were that (1) the Schizoraycctes 

 from the same generating substances, when introduced into different 

 nutrient fluids, present great variation in their development ; and (2) 

 Schizomycetes from diflerent generating substances, introduced into 

 one and the same nutrient fluid, also develop ditferently, and in part 

 produce also different decompositions; and hence that both the 



