290 Transactions of the Royal Mieroscopical Society. 
I had in my possession a maceration of haddock's head, which I 
had kept for fifteen months. At the time it was specially examined 
for experiment, it was found to contain in enormous numbers the 
''springing monad"* and the " calycine monad."! They were 
kept upon the " continuous stage " under examination for five days, 
and it was demonstrated that they were entering freely into the 
sac-condition and emitting spore. The little remaining moisture 
was evaporated slowly ; and at length the pulpy mass was taken out 
and placed in the heating chamber and gently raised to 150° Fahr., 
which was 10° higher than was required to kill the adults. It was 
kept at this temperature until it was quite dry and flaky ; and in 
some parts it was porous, cracked, and extremely friable, and under 
very little pressure crumbled into fine dust. A considerable quantity 
of this dust was obtained, and to prevent error was laid evenly on 
the surface of a plate of glass, and placed for ten minutes in the 
heating chamber at a temperature of 145° Fahr., 5° beyond the point 
needful to kill adult forms. This dust was now taken and diffused 
carefully through the air of a chamber like that used by Professor 
Tyndall.j: The condensed beam of an oxyhydrogen lime-light was 
sent through it, and it was found that the path of the beam was far 
more brilliantly marked inside the chamber than in the outer air ; 
it was therefore allowed to deposit its contained particles for four 
hours and a half, when the beam was found to be less briUiant but 
more uniform than in the air without the chamber. Ten small glass 
basins were now partially filled with the nutritive fluid, which was 
carefully mixed at the time. Six of these basins were open, 
and four were covered with a glass lid, which had an edge of some 
depth at right angles to its horizontal surface, which the more 
fully protected the contents from particles which merely fell per^ 
pendicularly. These vessels were inserted in the chamber, and the 
whole left for twenty-four hours. 
On the tops of the covers of the four covered vessels were small 
loops for handles. In the roof of the chamber a piece of brass 
tubing worked into a thick piece of sheet india-rubber with gly- 
cerine, and was quite germ-tight. By a simple mechanical con- 
trivance, a pair of light jaws could be made to open and close in 
this, and by means of these the looped covers on the vessels within 
the chamber could be taken off without interfering in the least 
with the chamber. This was done ; § so that now all the vessels 
were open to the air, which by no means allowed the beam to pass 
* • M. M. J.' vol. X. p. 245. t Ibid. vol. xiii. p. 191. 
% ' Philos. Trans.' vol. clxvi. part 1, p. 30. 
§ These covers were in all cases smeared witli glycerine on the outer surface, 
to avoid the danger in removal, which might arise from the disturbance of any 
germs or particles that might have been deposited upon them. 
