THE MICROMANIPULATION OF LIVING CELLS 



By ROBERT CHAMBERS 



DEPARTMENT OF BIOLOGY, NEW YORK UNIVERSITY, NEW YORK, N. Y. 



The micromanipulative or micrurgical 

 technique owes its inception in large mea- 

 sure to the natural urge of the investigator 

 to handle the object of his scientific 

 interest. 



Minute dissections, performed centuries 

 ago by men like Grew, Malpighi, and 

 Swammerdam with the use of magnifying 

 lenses or perspicilla, revealed delicately 

 small anatomical structures. These inves- 

 tigators, and others throughout the 17th 

 and 18th centuries, actually depicted cells, 

 but they did not realize the significance of 

 what they were looking at. They might be 

 likened to Tom in Kingsley's Water Babies 

 who, when he arrived at the sea, mistook 

 the water-babies for seashells and pebbles 

 and their laughter for ripples on the sand. 

 It was not till the turn of the 19th century 

 that the cellular constitution of living or- 

 ganisms began to be appreciated. The 

 diminutive size of the cells precluded the 

 possibility of dissecting them, so that of 

 necessity the attention was f ocussed mainly 

 on observational studies. However, some 

 investigators who were more experimen- 

 tally minded found means of testing the 

 material composing the cells. An early 

 method, occasionally in use today, was to 

 exert gentle pressure on a cellular tissue 

 placed between a slide and coverslip and 

 to note the effect of partially crushing the 

 cells. It seems fitting that such experi- 

 ments should have first been done on free- 

 living cells or Protozoa. By this means 

 Dujardin determined the fluid nature of 

 protoplasm which he termed sarcode. He 

 also observed that when the cell wall was 

 ruptured the interior would exude with- 

 out being destroyed. In one of his obser- 

 vations he took advantage of a chance 

 cotton fiber which lay across a Paramecium, 

 and by compressing the preparation he 

 caused a bulging mass of the protoplasm 

 to be completely pinched off. The result- 



ing fragment rounded up and the beating 

 cilia on its surface carried it away. 

 Another investigator, Carl Nageli, a botan- 

 ist, crushed plant cells, such as Yaucheria, 

 and found that the interior of the cell 

 could be extruded and separated off as 

 viable masses or bodies. 



Three important deductions can be 

 drawn from these early experiments: (a) a 

 bit of protoplasm isolated from the mass 

 of a cell may still exhibit properties of 

 life; {!)) the way in which the internal 

 material flows out of the cell and rounds 

 up indicates the fluid nature of proto- 

 plasm; and (c) the persistence of a sharply 

 defined boundary between the exuding 

 protoplasm and the surrounding medium 

 shows that the protoplasm must either be 

 non-miscible in water, or be able to recon- 

 stitute a membrane about itself. Pfeffer, 

 to whom we owe the term plasma mem- 

 brane, was convinced that the exuding 

 material maintains its integrity by the 

 formation of a precipitation membrane 

 about it. He noted that when such a 

 membrane did not form, the exposed ma- 

 terial became dissipated. Pfeffer was in- 

 terested in the osmotic phenomena of the 

 plasma membrane and attempted to deter- 

 mine its physical nature. In one of his 

 papers he actually proposed the possibility 

 of building a mechanical contrivance for 

 moving minute glass needles and pipettes 

 to permit operations on living cells. 



The nucleus was also the object of early 

 experimental study. W. H. Eansom, who 

 apparently has been overlooked by histor- 

 ians,^ published an article on the isolation 

 of the nucleus of the eggs of certain fish 

 in the PkilosopJvical Transactions of Lon- 

 don in 1867. He crushed the eggs in water 

 and in various salt solutions and observed 

 the effect on the extruded nuclei. His con- 



1 1 am indebted to W. E. Duryee for having 

 brought this article to my attention. 



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