1921] NATURAL SCIENCES OF PHILADELPHIA. 155 



Division is very frequent, and it seems curious that neither Alexi- 

 eeff nor de Beauchamp were able to observe it ; de Beau champ states 

 that when outside their host, the animals died in a few hours. 

 Moroff (25) , successfully cultivated his Euglena quartana, very nearly 

 related to Astasia, in an organic medium (pea-soup, etc.), and declares 

 that they thrive in purely inorganic cultures, but that after a very 

 little while they perish. 



For my part, I did not find any difficulty in keeping these organ- 

 isms in very good health for three to five and even six days, after 

 isolation in a drop of clear water on an excavated slide and under 

 protection of a cover. 



After creeping for a few hours, one of these big specimens con- 

 tracts into a perfect spherule, and there lies unchanged, for a vari- 

 able time, a whole day for instance; but if after having abandoned 

 the animalcule in the evening we examine our slide early next morn- 

 ing, we find then not one spherule but two, sometimes already four, 

 at 10 o'clock in the morning, those four are dividing again, con- 

 stricted in the middle, at 12 o'clock, eight spherules are present, 

 at 6 o'clock, sixteen are to be seen. On the following morning, the 

 number will be 64, and finally in the evening, after the 8th division, 

 one may count (approximately) as many as 256 small Astasia, 

 some contracted, some elongated and lanceolate, many of them 

 creeping or swimming round a lump of mucilaginous material where 

 most of the individuals are still imbedded. Eight divisions have 

 then successively taken place, after which the primitive single indi- 

 vidual has been turned into 256 little Flagellates. This number, 

 it must be said, must be considered as a maximum, which I never 

 saw exceeded, but have observed to be reached four times in my 

 eight experiments. At other times, however, long before attaining 

 that number the young animalcules begin to detach from the com- 

 mon mass; we should also note that this mass itself is not always 

 homogeneous, but may be very irregular in appearance. It is not 

 a cyst, in fact, just as the little spherules in the mass are not spores; 

 the jelly is more a fugitive secretion, which is easily destroyed, 

 and perhaps it is only on account of the absolute quiescence after 

 isolation on the excavated slide that the common mass remains 

 compact to the end. But, if we take the mass of jelly and carefully 

 compress it under the cover, these little spherules, born from di- 

 vision and destined to divide again, immediately begin to lengthen, 

 creep about, and change their form, just like adults, and this may be 



