SMALL MASSES OF ZOOGLCEA 191 



Some specimens of Cock's Foot Grass (Dadylis glomerata), just 

 as they had begun to flower, were gathered on June 14th. On 

 reaching home they were laid on a newspaper and placed within 

 a drawer, where they remained till July loth when an infusion was 

 made from small segments of the stalks and leaves. The infusion 

 was prepared with distilled water at 80° F. (27° C.) for three and a 

 half hours, when one portion of it was filtered in the usual way into 

 a small one-ounce beaker, and another small portion into a watch- 

 glass. The latter was covered by an inverted wine-glass, and the 

 former placed under a small bell-jar, by its side, and the tempera- 

 ture to which they were exposed for the next few days was about 

 73° F. (22° C). 



The fluid rapidly became turbid in each, and on examination, at 

 the expiration of 44 hours, of the pellicle that had formed in the 

 watch-glass I found it to be almost wholly composed of minute 

 Zoogloea masses, such as may be seen in the specimen represented 

 in Fig. 22, A ( X 150). By the next day many of these small masses 

 showed the first stage of change, two of which may be seen in 

 B ( X 500), close together. They were a trifle paler than the others, 

 while their contained Bacteria were rather less closely and regularly 

 aggregated. On the following day (fourth), in many of these altered, 

 paler areas, minute brown Fungus-germs of different sizes were 

 seen to be taking origin, such as are shown in C (x 500). The 

 minute brown bodies were found only in these paler and altered 

 Zoogloea aggregates ; while on the following day groups of such 

 aggregates, pardy fused, were becoming brown here and there, and 

 being converted into masses of minute Fungus-germs, as shown in 

 D (x 500). While many of the small Zoogloea masses remained 

 stationary for several days in this scum which formed on the shallow 

 fluid in the watch-glass, those that underwent change produced 

 only such small brown Fungus-germs ; which grew and speedily 

 multiplied, so as to form dense aggregates of small brown germs. 



Turning now to the portion of the same infusion in the small 

 beaker, in which the fluid had a depth of nearly two inches, its 

 scum when first examined, after 44 hours, was found to be almost 

 exactly similar to that shown in Fig. 22, A, from the watch-glass. 

 There was the same close aggregation of small Zoogloea masses, 

 though the scum itself was rather thicker than that on the fluid in 

 the watch-glass. Two days later (fourth day) many of the masses 

 were larger, and were segmenting into colourless units exactly like 

 those which commonly, at this early stage, develop into Monads or 



