HARD WICKE ' S S CIENCE - G OS SIP 



usually appear at two or three points on the surface 

 of the spore, were of two kinds ; some slender, un- 

 branched, and with very few septa, having the ap- 

 pearance of mycelioid threads, others originated as an 

 oval cell ; this gave origin to a second, by gemmation, 

 until a torula-like string was developed. P'rom this 

 chain, branches of a similar structure, increasing in 

 length by additions to the apex, were given off at 

 right angles, always originating from a septum of 

 the main branch. In about two days the oldest cells 

 of the chains contained a very bright, sharply-defined 

 nucleus, the constrictions became deeper, and soon 

 the chains broke up into separate cells, which, in the 





Fig. lo. — 5, Cells containing sporules ; 6, Spores ; 7, Showing 

 origin of capillitium ; 8, Spumaria alba, natural size ; all 

 the other figures magnified 500 diameters. 



course of twenty-four hours, had increased to many 

 times their original size ; owing to the swelling of 

 the cell wall, the nucleus, or bright speck, so con- 

 spicuous before the change, disappeared or became 

 converted into a homogeneous oval body in tlie 

 middle of the swollen mass ; sometimes two oval 

 bodies were present, possibly corresponding to the 

 two nuclei that were present in some of the torula- 

 like cells. The swollen cell- wall was somewhat un- 

 even and hyaline. Not the slightest sign of amceboid 

 movement was observed up to the formation of the 

 large resting-spores last described, which remained 

 unchanged throughout the summer, their progress 

 being noted from time to time by removing a few on 



the point of a moist brush rubbed amongst the heap 

 of moss. No change had taken place at the end of 

 August, 1880, when they were examined for the last 

 time, and a few days afterwards small portions of a 

 whitish watery-looking substance appeared on the 

 moss, which kept on increasing in size, until, on the 

 second day after its appearance, it presented the 

 usual characters of immature .Spumaria. Whether 

 this change was preceded by any movements remains 

 to be discovered. This is the stage at which the 

 plant first shows itself as a mass, consisting of a clear 

 liquid, crowded with very minute whitish granules, 

 exhibiting Brownian movements ; very soon a struc- 

 tureless pellicle forms on the outside, which is covered 

 with crystals of lime. The first indication of organi- 

 sation is met with in the cuticle, which presents 

 very minute and imperfect cells, the crystals at the 

 same time increasing in number and size. 



The production of these crystals, corresponding to 

 the raphides of flowering plants, proves two things : 

 I. That the plasma is at first chemically all alike, 

 because when a pellicle has formed and is coated 

 with crystals, if a portion from the centre of the 

 mass be exposed, a skin and crystals again form, and 

 this may be repeated several times. 2. That the 

 first changes in the plasma are due to physical 

 causes, evaporation, by which certain elements hold- 

 ing the salt of lime in solution have disappeared, 

 enabling the crystals to torrn, and favouring at the 

 same time, the formation of the external pellicle, 

 which remains for a considerable time without trace 

 of organization. 



After the formation of the cuticle the internal 

 pulpy homogeneous mass presents numerous bright 

 specks, each being a focus round which a portion of 

 the plasma resolves itself into a large naked cell of 

 irregular shape. This is the " plasmodium," the 

 large cells just formed exhibiting during the first 

 day very active amoeboid movements, changing their 

 shape completely within five minutes, the original 

 bright nucleus either disappearing or changing into 

 a large round vacuole, carried along with the most 

 active part of the cell. At the end of the third day 

 all movements had ceased, the cells assumed a spherical 

 shape, bright nuclei appeared amongst the granular 

 contents, and within twenty-four hours of this change 

 the cell wall was absorbed and the mature spinulose 

 spores were free. During the amoeboid stage gobular 

 cells, furnished with a long neck, appeared in small 

 quantities ; they contained minute oval sporules, 

 which escaped, when mature, through the neck in 

 large quantities ; some were kept for a time in a 

 damp cell, but no change was observed. 



The capillitium is formed as follows : When the 

 amceboid cells form round the bright nuclei in the 

 homogeneous plasma, they are not crowded, but 

 portions of plasma not used for the formation of the 

 cells remain and constitute the capillitium ; im- 

 mediately after formation the cells shrink consider- 



