1872.] 



Modes of Origin of Infusoria §c. 



251 



and each appeared to have grown up in the situation in which it was seen*. 

 These corpuscles gradually became more numerous, on to the tenth day, 

 though they underwent no appreciable change except a slight increase in 

 size. On the eleventh day, in the portion of the pellicle which had been 

 transferred to the fresh hay-infusion, many of these stationary bodies, like 

 the Monads and active Amoebae, were found to have increased to such an 

 extent as to have doubled their transverse measurement. They had also 

 developed a distinct nucleus in their interior (of a ring-like character), 

 vacuoles appeared and disappeared at intervals, and at the same time they ex- 

 hibited slow and slight amoeboid changes in outline (fig. 4, g,h, i); they were, 

 in fact, now obviously converted into sluggish Amoebae. On the seventeenth 

 day many of them were recognized iu the pellicle, scattered amongst the 

 already-described encysted Amoebae. They had again become motionless 

 and slightly contracted in dimensions ; whilst their outer layer was con- 

 densed, but not decidedly cyst-like. Many of the smaller sizes were also 

 seen. Seven days afterwards (twenty-fifth day), when another portion of 

 the transferred pellicle was examined, it was found to be densely studded 

 throughout with thousands of encysted Amoebae, the great majority of 

 which were of the first variety and were pretty uniform in size and appear- 

 ance. But interspersed amongst them were a considerable number of the 

 imperfectly encysted Amoebae, of different sizes (b). Here and there, how- 

 ever, some of them (now mostly about y -gVu" m diameter) presented an un- 

 usual appearance. They had assumed a faiut brown hue throughout their 

 whole mass, and segmentation had gone on within so as to produce a number 

 cf units, whose shape seemed irregular, owing to their being so densely 

 packed (c) . Other masses were seen in which considerable growth had taken 

 place — these being nearly twice the size and irregular in outline (d), though 

 still of a faint brown colour, and composed of a mass of densely packed 

 units, which were held together by an almost invisible bounding mem- 

 brane. And, lastly, in other places small aggregations of brownish 

 spores were seen (e), which had been liberated by the solution of this 

 very attenuated membrane — the separate spores being tolerably thick- 

 walled, bilocular bodies, 40V0" * n l en n tn D y tt^ou" * n breadth. An 

 examination on subsequent days showed many other of the amoeboid 

 bodies breaking up in a similar manner into these brownish, biloculated 

 Fungus-germs. 



But, strange to say, brown Fungus-germs of an almost similar character 

 had previously presented themselves on the surface of the original infusion, 

 although they had arisen in quite a different manner — by a process of 

 Archebiosis. 



In the original infusion, when (on the tenth day) the Amcebae commenced 

 encysting themselves, portions of the pellicle began to sink to the bottom 



* These bodies were evidently quite different from Mon as and its amoeboid dervatives, 

 all of which shrivelled very much when mounted in glycerine-jelly, though the cor- 

 puscles which I have just been describing were not appreciably changed. 



