76 H. MARSHALL WARD. 



apertures) from their envelope, and moved away very slowly as 

 myxamoebse (fig. 16, i). 



In the drop of water containing the spores, the germination of which 

 has just been described, there were relatively large quantities of organic 

 debris, as well as Bacteria and numerous Infusoria and other oxygen 

 consumers, and I have very little doubt that what was abnormal in the 

 process was due to the want of oxygen caused by these organisms ; 

 for although it was impossible to show this directly, subsequent 

 experiments proved that an additional supply of fresh water caused 

 the dormant myxamoebae to become active again, and I found that 

 the more free the cultivations were from Infusoria and Monads 

 especially, the longer the myxamcebEe tended to be active. Bacteria 

 need not be absent, though of course there may be too many of them : 

 there are even facts pointing to the conclusion that within certain 

 limits the Bacteria not only do no harm, but even serve as food. The 

 deprivation of oxygen, then, no doubt accounts for the tardiness of 

 some of the processes described ; while it seems not improbable 

 that the curious phenomena which took place during the germination 

 of the specimen to which fig. 16 refers, were connected with nuclear 

 division, however difficult it may be to follow the connection in detail. 



It now remains to describe what may be termed the normal process 

 of germination which occurs when sufficient precautions are taken to 

 avoid an accumulation of oxygen-consuming objects in the cultivation 

 and, it may also be added, when the temperature is a little higher than 

 before ; I have satisfied myself, however, that the spores can germinate 

 normally when the thermometer in the laboratory stands at 18° C, and 

 even lower. I will describe the germination first, and the methods 

 employed afterwards. 



On the rupture of the thin-walled papilla (c. /. figs. 11 and 14) the 

 two myxamoebee escape very rapidly, and at once begin to move about 

 actively, and close examination now shows that each possesses a single 

 flagellum — a long, very thin, but tapering, stiff cilium, the free end of 

 which is exceedingly flexible — in addition to the evident nucleus, and 

 now actively pulsating vacuole. The vacuole slowly expands, taking 

 about f of a minute to fill, and then closes with a rapid wink-like action, 

 to repeat the process almost immediately. The nucleus offers nothing 

 remarkable, so far as I could determine ; it and the fine granules are 

 in the more internal portions, and are constantly changing their posi- 

 tions as the amoeboid movements proceed. The flagellum stands out 



