1878.] the Life-History of a Minute Septic Organism, 339 



and continuous to the end. When first seen, these exquisitely 

 minute specks are strongly opaque ; but as they are attentively 

 watched with a magnification of 5,000 diameters, they, in the course 

 of from twenty to forty minutes, become quite clear, and would be 

 much more difficult to find in this condition than when first poured 

 out. But, following upon this, there is a distinct elongation, which is 

 indicated at fig. 18, and this proceeds so that, at the end of an hour 

 and a half, they were in the shape and relative size shown at fig. 19. 



On the first and second occasion on which the observations were 

 made, very little was made out, except the succession of the meta- 

 morphoses ; but on subsequent occasions, when a careful scrutiny for 

 the discovery of delicate changes was made, the clear, sharp, defining 

 power of the new T V^ n objective was of great service ; by its means I 

 was enabled to discover the first indication of the origin of the anterior 

 and lateral flagella in the developing germ. At the end of an hour and 

 a half after emission from the sac, the long oval form which the germ 

 had taken (indicated at fig. 19) was always associated with a sharpen- 

 ing at one end. This became rapidly sharper and longer, as seen in 

 fig. 20, at 4 and 6. This always developed into the anterior flagellum. 

 But at about the same time — generally about two hours after emission 

 from the cyst — there were pushed out two delicate points of sarcode 

 laterally, and at right angles to the beak in front ; 1, 2, 3, 5, fig. 19, 

 are copies of camera drawings of this condition in the minute germi- 

 nating body ; and the extremely delicate lateral points were found by 

 close watching to develop into the lateral flagella of the perfect form. 

 The growth was now much more rapid ; fig. 21 represents the changes 

 that had taken place in forty minutes after the condition depicted in 

 fig. 20. And now slight movements began in some of the better de- 

 veloped forms, such as a, fig. 21. They were not changes of place, 

 but movements of the lateral and anterior flagella, and occasionally a 

 change of the direction in which the bodies lay. In the course of 

 another hour the neck-like protrusion at the base of the anterior 

 flagellum generally appeared as shown in a, b, fig. 22, and very soon — 

 in every instance less than a quarter of an hour after — short move- 

 ments of translation begin, which resulted in ten minutes more, in 

 graceful swimming. Fig. 23 is a copy of a drawing made of one of 

 these forms that had reached the condition the drawing depicts in 

 a little over four hours from the time of emission from the sac. It was 

 then the -goVo tn of an inch in long diameter, just one-half the size of 

 the adult ; but it was perfect in form, even to the possession of a 

 nucleus, and swam with freedom and grace. Its increase of size from 

 this time was even more rapid, for in the course of another hour it 

 had passed through the size and condition seen in fig. 24, to the 

 normal parental size depicted in fig. 25. And if, after it had reached 

 this state, it were still persistently followed, it might be in ten or 



