100 Transactions of the 



piece of paper is laid on the top of the other, and then the parts 

 k, Z, m, &c.. being carefully raised, the slip may be inserted so 

 that the blotting-paper covers it and yet leaves a vacant space all 

 round the cover. If now a thick piece of plate glass be laid upon 

 the top of the tray, a moist chamber is formed in which the slips 

 may preserve the drop of fluid moist for an indefinite time. By 

 constantly examining them we were enabled to report what changes 

 might be ensuing from hour to hour, and when not being examined 

 they were simply replaced in the chamber. 



It will be seen that by this means no precautions were employed 

 for the exclusion of extraneous germs or other organisms ; but then 

 none were needed. We disregarded whatever else might appear 

 besides the forms ivhose germs we kneiv existed in, the jiuid before 

 heating; and we confined ourselves solely to the developynent of 

 these. And on this subject no mistake coidd arise, for ive had 

 made ourselves masters of their life history. 



Of the three forms which we describe in our " Further Re- 

 searches, &c.," it will be remembered that the first emitted palpable 

 germs. The second was, to use a concise term, viviparous, emitting 

 no germs but the cyst opened to give birth to minute living forms. 

 The third, which we describe in this communication,! emits a 

 sporule which is undiscernible by any powers we could employ. 

 As we do not venture to name these forms, we will designate them 

 as I., II., III., which indicates the order of our communications 

 on " Further Eesearches, &c." ; but as II. emitted living monads 

 instead of spores, we will keep this before the reader by placing an 

 asterisk beside the II., thus II.* 



1. Six slides were taken, and on examination were found to con- 

 tain all three of the above forms, and in almost every stage. These 

 were placed in the heating box, and the temperature slowly raised to 

 82 • 22 C. ; they were kept in this temperature ten minutes ; then 

 allowed slowly to cool. 



On examination after moistening, nothing could be seen in the 

 field but an amorphous mass. Not a trace of motion could be seen 

 with the best light and 2500 diameters. 



These were now placed in the moist chamber and examined at 

 intervals, with the following results in eight hours and a half, viz. : 

 On all six of the shdes young of III. ; on five of them young of I. ; 

 on one only of them young of II.* Subsequently drawings of 

 development of each of these were made from these slides. 



2. Six more slides were prepared from the same solution, and 

 found on examination to contain I., II.*, III. They were kept in 

 a temperature of 93 • 33 C. for ten minutes. On examining them 

 after moistening, they presented the same aspect as before : no trace 

 of motion, and no semblance of life. They were placed in the moist 



t The former part of this paper was printed in the Ftbruary nnnjber of this 

 Journal, p. 69. 



