ST. 



BAIRD &TATLOCK. (LONDON) LTD. 



317 



317 s Opsonic Incubator, copper, with our new pattern Automatic Regulator (Registered No. 

 536814), adjusted for a temperature of 37 C., with twenty water-jacketed tubes for blood 

 pipettes, and ten tubulures for carrying culture tubes. The automatic gas regulator is 

 similar to that described under No. 301. Price with burner .. .. .. .. 4 15 



318 s Pipettes, for use with above, straight . . . . . . per doz. 8d. ; per gross 070 



319 s curved .. .. .. lid.; 10 



320 s Tubercle Bacilli, for making emulsion for opsonin testing, in tubes.. '. . each 5 





321 



Electric Signal Timing Clock. 



This instrument was originally designed as an automatic electric bell signal for timing the 

 period of incubation of the blood tubes, in Dr. Freeman's opsonic incubator as used in Dr. Sir A. E. 

 Wright's laboratories, at St. Mary's Hospital, W. The clock, can, however, be used for electrically 

 noting periods of time from one minute, by multiples of one minute, to one hour, and as such can be 

 arranged for physiological and other experimental work. The working of the apparatus is ac- 

 complished by means of a metal plate which surrounds the clock, this plate having a series of sixty 

 holes of equal distance apart corresponding to minutes in the clock. In the centre of these holes a 

 metal rod is fixed, the other end of this rod passes through an insulating ring and projects inside 

 Ihe clock face where it makes contact with the hour hand of the clock. A small metal plug inserted 

 in the hole in the metal plate short circuits this and the metal rod, and thus signals the time when 

 Ihe hand of the clock makes contact with that particular rod. The clock is of an American type 



CROSS STREET HATTCTST GARDEN, E-C 



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