1892. ] Automatic Device for Rolling Cnlture Tubes. 155 
It consists of a tin jacket, with rectangular pérforations and 
bristling with ‘‘paddles,” which grasps the tube and upon 
which the stream of water is so directed that it furnishes not 
only the motive power for whirling the tube but also the cold 
bath to solidify the agar agar. This device, quiet and in mo- 
tion, is shown in figures 2 and 3 in plate XI. 
The jacket I made in about an hour's time. It is quickly 
and easily slipped from one tube to another. The frame work 
which rests across the edges of the sink and holds the sup- 
Ports for the tube was the work of a few moments. The 
7-7 
F : s 
; IGURE I.—Qutline of jacket for rolling culture tubes, Full size. 
Jacket 
tin og made from a single piece of tin as follows: The 
Straight iy Cut the exact size of figure 1, three edges being 
Placing : ile one edge was cut as shown in the figure. Now 
Narrow ¢ 2“ sheet of tin upon a block of wood, with a quite 
Tegular lin. *P chisel cuts were made corresponding to the ir- 
Vise “gh » © etc. The sheet was then placed in a 
tendiculariy ” and the four rectangular projections bent 
ise] wn...) °° the sheet in the same direction that the 
ANd S69 on uri, . Lhe sheet is then raised to the line 4 4, 
until all the small rectangular pieces are bent out to 
