Section IV, 1918 [41] Trans. R.S.C. 



A Report on Results Obtained from the Microdissection of Certain Cells. 



By Robert Chambers, Cornell University Medical College ,^___^^^^ 



New York City. y^Ç^iÂCÏ^^ 



Presented by J. Playfair McMurrich, F.R.S.C. 



(Read May Meeting, 1918.) 



Introduction. 



Cytological research has hitherto been confined largely to observa- 

 tion through the microscope 'at a distance' as it might be said. It 

 has been clear to investigators that such a method may lead to errone- 

 ous conclusions and it is true that a great deal of confusion has resulted 

 from misinterpretations of optical appearances and the description 

 of artifacts as if they existed normally in the cell. This confusion 

 is largely responsible for the fact that the true significance of cell 

 anatomy is in danger of being ignored by many physiologists. 



As long ago as 1859, Doctor H. D. Schmidt of Philadelphia, 

 attempted to dissect cells by means of a 'microscopic dissector,' 

 consisting of a base to be fastened on the stage of a microscope with a 

 number of clamps to hold instruments, each clamp possessing three 

 movements controlled by screws. A lever fastened in one of the 

 clamps holds the tissue in place. Fine scissors, knives or steel needles 

 are fastened in the other clamps. By turning the various screws, the 

 instruments can be brought into place and be operated with remark- 

 able accuracy. Doctor Schmidt worked with the tissue, the instru- 

 ments and the lower lens of the objective immersed in water or diluted 

 alcohol. 



The principle introduced by Schmidt, viz., the use of screws 

 to control movements of instruments lying in the focus of a micro- 

 scope objective seems to have been for a long time lost sight of. It 

 was revived in 1907 and el^iborated in 1914 by M. A. Barber, lately 

 of the University of Kansas, in his construction of an instrument to 

 manipulate micro-pipettes. With this instrument Barber was able 

 to isolate single micro-organisms and to inoculate living cells with 

 bacteria. Barber's instrument was soon applied to the dissection of 

 cells (Kite and Chambers '12) and a new field of endeavor was 

 opened for the study of the structure of protoplasm and cell mechanics. 



