1878.] the Life-History of a Minute Septic Organism. 341 



had been filled with water, to which a little filtered fowl broth was 

 added as nutriment. These tubes were then hermetically sealed, and 

 heated up to 310° F. in a digester. These were kept in absolnte 

 alcohol, so that the outsides of the tubes might not contract dust, and 

 so forth. 



The contents of these tubes were now used to remoisten the dried 

 film beneath the cover-glass. The ends of the tubes were broken off, 

 and by capillarity the fluid was drawn beneath the cover, at the edge 

 of which the now open end of one or more of the tubes was applied. 

 In this way a plentiful supply of moisture was given. 



It was now placed again in the " continuous stage " and examined. 

 At the end of four to five hours the fluid film looked almost every- 

 where clear, and as it appeared before heating ; but I was not able by 

 any method I employed to discover the minute spores, nor could I find 

 in this one the earlier stages of development ; but at the end of seven 

 hours, while " searching " with a low angled T \-th inch objective, I 

 saw three forms in about the state of development shown in fig. 23, 

 Plate 9 ; and in the course of another hour a great increase in their 

 number had taken place, and in three separate instances they were 

 followed from the time they were first seen into full development and 

 the commencement of fission. 



When more cysts were found this entire process was again repeated 

 twice at the same temperature, and at the expiration of ten and eleven 

 hours respectively adult forms in full activity were found ; and in the 

 latter of these two instances I discovered the organism when it was in 

 the still condition of development, represented in figs. 20 and 22, 

 Plate, 9. It was thus manifest that by this method of heating a tem- 

 perature of 210° F. could be completely resisted. 



Following the above process in every particular, I next, as they 

 could be found, subjected the spores to 260° F. I did this on three 

 glass squares (as before) in succession. But in no one of these did 

 the organism reappear, although examination was repeatedly and care- 

 fully made for five days. 



It thus appeared that a temperature of 260° F. applied in this way 

 was fatal to the form, for on taking a needle-point of the septic fluid 

 containing the organism in abundance, and, touching the edge of the 

 fluid with it, I found that in the course of four or five hours there were 

 hundreds swimming in full vigour, showing that the fluid was capable 

 of sustaining the organism, if it were in a vital condition in the fluid. 



I next experimented at 10° F. lower, viz., 250° F. I did this on the 

 contents of two separate cysts. In the one case, after ten hours, there 

 was a re-appearance of the living organism, but only two or three 

 adults could be then found ; and the increase that afterwards ensued 

 was dependent upon fission, for no small forms could be seen. In the 

 ether case, there was rather a larger number of adults at the end of 



