644 



SUMMARY OF CURRENT RESEARCHES RELATING TO 



Toldt's* (fig. 110) is similar to the preceding, but in addition to 

 the vessel containing the injecting fluid, a second air-vessel is 

 introduced. 



Thanhoffer's.'\ Prof. L. v. Thanhoffer uses the following apparatus 

 (fig. 111). To the wall of the room and near the ceiling a board is 

 fixed. This board carries a pulley, over which a cord is passed, having 

 at one end a large glass vessel A, filled with water ; at the other end of 

 the cord is a handle, by which the vessel can be drawn up and down 

 as required. When the tap in A is open, water flows through the india- 



FiG. 109. 



Fig. 110. 



rubber tube into a second vessel B, which acts as an air-reservoir. 

 The air compressed in B passes into C, which contains the injecting 

 fluid, and forces it through the discharge pipes and thence into the 

 vessels. The pressure is of course increased according as A is raised. 

 The amount of pressure is denoted by the manometer M. Quicksilver 

 may be substituted for water, and greater pressure thereby obtained, 



* Thanhoifer's 'Das Mikroskop unci seiue Anwendnng,' 1880, p. 189 



(1 fig.)- 



t Ibid., pp. 190-2 (1 fig.). 



