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XVI.— NEW APPARATUS AND 
METHODS FOR THE DISSECTION AND INJECTION 
OF LIVING CELLS. 
By Professor Robert Chambers, 
Cornell University Medical College. 
{Read October 18 , 1922 .) 
Seven Text-Figures. 
1. Introduction. 
Operative work on the living cell has long been the aim of 
investigators in cytology and in experimental embryology. 
It was not, however, till Barber developed his method that any 
serious attempt could be made to dissect cells under magnifications 
high enough to enable one to observe in detail the various steps of 
the operation. The big feature of his method, aside from the 
making of needles and pipettes stiff and yet fine enough to puncture 
red-blood corpuscles, consists in his moist chamber, which allows 
the needle tips to be operated in a drop hanging from a coverslip in 
the moist chamber. This method eliminates all interference between 
the objective and the coverslip, thereby permitting the use of the 
highest-powered objectives. Unfortunately his instrument for 
manipulating the needles, unless very skilfully made, has too much 
lost motion, and wear and tear soon renders the movements jerky 
and undependable. 
Barber uses his apparatus principally for the isolation of 
bacteria. In 1912 Kite (Kite and Chambers, 1912) applied 
Barber’s method to cytological investigation. The difficulty of 
handling Barber’s apparatus limited the number of investigators 
in this field, and as the work in micro-dissection progressed the 
need of a more accurate and simple instrument became imperative. 
The instrument described in this paper, a preliminary account 
of which has been published (1921), is a simplified modification of 
one which I have been using for two years. It has the following 
advantages over any instrument hitherto made : (a) simplicity of 
construction ; ( b ) absence of any lost motion, no matter how long 
the device is used; (c) accurate and continuous control of the 
needle or pipette tip in any direction under the highest magnifica- 
tions of the microscope ; (d) maintenance of the needle tip in one 
plane while it is being moved back and forth in any of the three 
directions ; and ( e ) inclusion of adjusting devices which facilitate 
placing the needle or pipette into position. 
2 c 
