CELL AND PROTOPLASM CONCEPTS 



event of 1839 and celebrate its centenary 

 in 1939, as if it had no antecedents — as if 

 it were a creation rather than an evolution. 



These remarks apply with especial force 

 to the origin of the cell theory. This sym- 

 posium was designed in part to celebrate 

 the centenary of the cell theory of 

 Schleiden and Schwann, but the cell theory 

 in all its fundamental features is older 

 than either Schleiden or Schwann. Their 

 cell theory was a special and, in important 

 respects, an erroneous one. Since there is 

 no present biological interest in their par- 

 ticular theory, it is amazing that we still 

 continue to call the great conception that 

 the cell is the universal unit of organic 

 structure and function after them, as if 

 they were its sole discoverers, thus embalm- 

 ing the names of two scientists, distin- 

 guished for other discoveries, with one of 

 their most serious blunders. 



Greek philosophers and naturalists, and 

 especially Aristotle, are said to have 

 reached the conclusion "that animals and 

 plants, complex as they may appear, are 

 yet composed of comparatively few elemen- 

 tary parts frequently repeated" (Locy 

 1908). But there is no doubt that these 

 elementary parts were the roots, stems, 

 nodes and internodes, the leaves and flow- 

 ers of plants and the segments, organs and 

 other parts of animals that were visible to 

 the unaided eye. The discovery of the fun- 

 damental elementary parts, the cells, was 

 not possible before the invention of magni- 

 fying lenses. It is probable that the use 

 of simple lenses was known to the ancients. 

 Pliny the Elder says that crystal globes 

 filled with water were used as burning 

 glasses. Seneca remarks that small letters 

 are enlarged when seen through such glass 

 globes. Nero, who was near-sighted, is 

 said to have used a large emerald as a dis- 

 tance glass. Coming to more recent times, 

 spectacles for far or near sight were in- 

 vented by d'Armato of Florence about 

 1300. Roger Bacon is said to have invented 

 biconvex reading glasses in 1270, but ap- 

 parently his invention remained unknown 

 to the world for nearly 500 years. It has 

 also been claimed that he invented the com- 

 pound microscope, but if this be true it 



also remained unknown until William 

 Romaine Newbold deciphered the Voynich 

 manuscript (1921). 



The invention of the compound micro- 

 scope is generally attributed to Hans and 

 Zacharias Janssen, father and son, grind- 

 ers of spectacles in Middleburg, Nether- 

 lands, between 1590 and 1609. In 1610 

 Galileo made a microscope which he called 

 Occhiale, ''that made a fly look as big as a 

 hen"; and, as is well known, he also in- 

 vented the telescope. The names micro- 

 scope and telescope originated with Gio- 

 vanni Faber of the Academia de Lincei 

 about 1625 (Carpenter 1891). 



II. Origin and Development of the Cell 

 Theory 



Cells were first seen, named, described 

 and figured by Robert Hooke^ (1635-1703), 

 an English scientist and architect, 170 

 years before the work of Schleiden and 

 Schwann. Hooke had been a student at 

 Christ Church, Oxford, and assistant to 

 Robert Boyle, author of "The Sceptical 

 Chymist, " 1661. In the year that the 

 Royal Society received its charter, 1662, he 

 was appointed curator of experiments and 

 his duty was to furnish the Society at their 

 weekly meetings with three or four consid- 

 erable experiments. This he did satisfac- 

 torily for forty years in spite of the fact 

 that most of the instruments for experi- 

 ments had to be made by himself. His ex- 

 periments covered the whole range of the 

 science of that time and led to a great 



1 Hooke was a man of amazing versatility, one 

 of the best mechanics and inventors of his age, a 

 good mathematician and physicist and for thirty- 

 eight years professor of geometry in Gresham Col- 

 lege. After the great fire of London in 1666 he 

 drew plans for the reconstruction of the burned 

 over area which were approved by the Royal Soci- 

 ety and the Common Council of London. He was 

 appointed surveyor of the City and was responsible 

 for widening the streets, and the building of the 

 Monument, Bedlam Hospital, Montague House, 

 College of Physicians et al. "His active, jealous 

 mind conceived that almost every discovery of his 

 time had been initiated by himself and this anxiety 

 to claim priority induced Newton to suppress his 

 treatise on optics until after Hooke 's death in 

 1703." (A. E. Shipley in Cambridge History of 

 English Literature, -vol. 14, 1916.) 



