636 



APPENDICES. 



Meyer's Thermo-regulator is represented in Fig. 271. No. I. 



shows the construction of the regulator : its inner tube terminates 



in an oblique opening, and is also provided with a minute lateral 



perture, which prevents the complete shutting off of the gas supply. 



Fig. 271. — Meter's Theemo-ebgulatoe. 



No. II. illustrates the method of introducing the mercury by suction 

 through a filling tube, which is substituted for the inner tube of the 

 regulator. No. III. represents Frankel's modification of the same 

 instrument. 



(M) Inoculating and Dissecting Instetjments and Apparatus 

 IN Common Use. 



Mouse-cages. — As mice are the animals most frequently 

 employed for experimental purposes, mouse-cages have been 



