82 h. marshall ward, 



The Plasmodium. 1 



On the roots of the Hyacinths on which the sporangia were situated, 

 it was not difficult to find larger and more complex amoeboid masses 

 of protoplasm (fig. 24a) and among the sediment at the bottom of the 

 glass cylinder occurred very similar specimens (fig. 246) which, how- 

 ever, seemed as a rule less active. Since those on the roots were 

 mingled with myxamoebae, bacteria, spores of the myxomycete, and 

 sporangia in all stages, it may no doubt be inferred that they are 

 the plasmodium produced by the fusion of the myxamooba?. The 

 inference becomes very near certainty after watching the specimens 

 under cultivation. In fig. 22 are drawings of myxamoebse from a 

 much larger aggregate which were found in a culture kept under 

 observation for 11 days. These myxamoebae were cultivated from 

 the spores, and had passed through the stages of division and encyst- 

 ment, and by this time outnumbered the original spores at least 

 eighty or a hundred to one. They were now moving sluggishly about 

 on the glass, and also on the lower surface of the suspended drop of 

 nutrient fluid : the nuclei were quite distinct, the vacuoles pulsating 

 slowly and at long intervals, and the flagellum appeared to have 

 been withdrawn in all cases. It was not until I had seen such 

 cases, where the sluggish myxamoebge glide slowly over one another 

 for some time, that it became clear that this is a preparatory 

 stage to the formation of plasmodia. I then had opportunities of 

 examining the process more in detail : as the myxamoebte approach 

 more closely to one another, they slowly glide over one another, in 

 undoubted contact, but without sticking or blending together in the 

 least. It appeared at times as if an extremely delicate investment 

 separated them — if such an investment exists, however, it must 

 follow every movement of the protoplasm. As fig. 25 shows, some of 

 them may still retain the flagellum, but the majority have lost it, and 

 all do so eventually : the conditions figured at a to c (fig. 25) were 

 drawn at intervals of 2 minutes, and d 5 minutes after c, to show 

 this slow " swarming " process, as it might be termed. 



Later on, after from 12 to 30 hours, several relatively large plas- 

 modia were found on the slide, and that these were formed by the 

 fusion of the myxamoebBe was evident from the fact that the process 

 was still going on. As shown in fig. 23, larger masses of plasmodium 

 were being added to by smaller ones and by myxamoebse, which now, 



1 Cf. De Bary (op. cit., p. 455), and Zopf, p. 22, for a general description of Plasmodia. 



