PLATE LI. 



EXPLANATION. 



Fig. 



1-5. Illustrating the apparatus employed by Messrs. Dallinger and Drysdale during 

 their prolonged investigation of the life-histories of various monads referred 

 to at vol. i. p. 116, originally figured and described in the ' Monthly Micro- 

 scopical Journal for March 1874.— i, a a, glass plate adapted to fit the stage 

 of the microscope ; b, circular aperture cut in the plate, a thin piece of glass 

 f, ^, ^,/ being cemented over it to permit the near approach of the achro- 

 matic condenser ; g g g, brass socket with ring attached which is fixed with 

 marine glue to the projecting arm of the glass plate «, and supports a cylin- 

 drical reservoir of water, Fig. 4 ; hh h h, outline of position of bibulous paper 

 having central aperture and tongue-like projection which dips down into the 

 reservoir fitted to the socket g ; 2, bibulous paper cut to fit the glass stage, 

 the portion <5 c leading into the reservoir^ of Fig. i ; 3, moist chamber con- 

 sisting of a short piece of glass tubing a, having the bottom edge e carefully 

 ground, the top having over it a thin elastic film with a minute central per- 

 foration c, and securely fastened to the sides at the groove d ; 4, cylindrical 

 glass reservoir fitting into the socket^ of Fig. i, and into which the project- 

 ing arm of the bibulous paper dips ; 5, the entire apparatus in working order, 

 the object glass g being racked down through the central perforation of the 

 elastic film/ of the moist chamber ch ; a a section of glass stage ; b, aperture 

 in the same ; c, the glass cemented over the aperture ; d, covering glass over 

 object examined ; e, walls of moist chamber. 

 6. Chamber invented by Professor Tyndall, referred to at vol. i. p. 130, originally 

 figured and described in the 'Transactions of the Royal Society,' 1877, 

 for the perfect isolation and cultivation of organic infusions and equally 

 suited for a similar culture of Infusoria, c, central box or chamber, the 

 front being removed showing the windows w, w, for the admission of light ; 

 /, six test-tubes fitting with an air-tight packing into the floor of the chamber ; 

 a, b, sinuous glass tubing permitting the access of air but not of germs to 

 the chamber ; p, pipette with stuffed funnel, fitting into a pin-hole perfora- 

 tion in a piece of indiarubber and stuffing-box containing cotton-wool 

 moistened with glycerine, and thus permitting its insertion and withdrawal 

 without the introduction of adventitious germs. 



