QUARTZ ROD TECHNIQUE 



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QUARTZ ROD TECHNIQUE 



dependent of the purposes of those who 

 use it. Methods are always dependent 

 upon purposes. Analytical mecha- 

 nistic biologists are working on the solu- 

 tions of many problems including: How 

 are the bodies of the adults of each 

 species constructed? How does each 

 body develop? How does it change 

 with time? How is it constructed while 

 it is alive? How is it constructed so 

 that it can function? What physical 

 and chemical functions does each small 

 part have? During each phase of 

 physiology how does each small part 

 behave? How do the coordinated func- 

 tions of the small parts summate? How 

 does the function or functions of each 

 small part contribute at each moment 

 to the integrated symphony of the 

 functioning of the whole? Further, 

 what can go wrong with each part? 

 And in addition the clinical sciences 

 continually ask, "What can we do to 

 prevent or help repair whatever can go 

 wrong with each part, with each group 

 of parts, with the integrated function- 

 ing of the body as a whole?" 



Histological studies are made for a 

 definite purpose, to help collect evi- 

 dences from which to develop accurate 

 concepts of the structure, functioning 

 and responses of the small parts of liv- 

 ing bodies. When we have accurate 

 concepts of the structure and behavior 

 of small parts then we can deal induc- 

 tively with this information and so 

 build up concepts of the functioning of 

 whole organs. Our current more trust- 

 worthy concepts of the structure and 

 function of the kidney were built up by 

 this inductive approach (Vimtrup, Bj., 

 Am. J. Anat., 1928, 41, 123-151; Rich- 

 ards, A. N., Proc. Royal Soc. London 

 B. 1938, 126, 398-432), which is exactly 

 opposite from trying to deduce the 

 function of microscopic parts from the 

 results of gross experiments performed 

 on whole organs or systems. 



Each living animal lives in four di- 

 mensions, three of space and one of 

 time. At any moment each feature of 

 an animal's structure exists in the three 

 space dimensions. But many features 

 of the spacial architecture undergo 

 rapid or slow cyclical, intermittent, or 

 progressive changes with time. The 

 chemical and physical characteristics, 

 the shapes, the magnitudes and the 

 positions of structures change as parts 

 of development, of physiology and of 

 pathology. New structures appear and 

 old ones disappear. These are changes 

 along the time dimension. The rates 

 at which changes occur are most impor- 

 tant parts of our concepts of the struc- 



ture and functioning of the small parts 

 of living bodies. 



The usefulness of microscopic studies 

 of living organized tissues (as opposed 

 to tissue cultures) becomes most appar- 

 ent when one recognizes the limitations 

 of histological sections. A histological 

 section is not the original living mate- 

 rial. It is only a two dimensisnal slice 

 out of a four dimensional system, minus 

 what had been lost and plus what has 

 been added in its preservation-prepa- 

 ration. No one can possibly begin to 

 appreciate "what has been lost" in the 

 preparation of histological sections un- 

 less and until he studies tissues by 

 methods which do not involve any of the 

 steps commonly used in preparing 

 sections. 



The spacial dimensions of living 

 tissues are invariably altered in the 

 preparation of histological sections. 

 The alterations in dimensions fre- 

 quently or usually are as great or 

 greater than the changes in dimension 

 which microscopic structures undergo 

 as parts of their own physiologic proc- 

 esses. Hollow structures, for example, 

 liver sinusoids, collapse during death 

 and fixation, their fixed tissue dimen- 

 sions becoming less than meaningless. 

 Knowledge of the exact dimensions of 

 structures, the surface areas of vascular 

 networks, the surface areas of glands 

 etc., are urgently needed as a basis for 

 quantitative physiological work. 

 (Krogh, A., Anatomy and Physiology 

 of Capillaries, New Haven: Yale Uni- 

 versity Press, 1929, p. 46.) It cannot 

 be too strongly emphasized that for 

 strict, mathematical treatment of phys- 

 iological problems (Bloch, I., Bull. 

 Math. Biophysics, 1941, 3, 121-126, 

 ibid., 1943, 5, 1-14) measurements of the 

 dimensions of microscopic structures 

 taken from fixed tissues, untempered 

 by knowledge obtained from the living, 

 cannot be used. For after the abuse 

 which the tissues undergo in death and 

 fixation, shrinking and swelling in vari- 

 ous reagents, and the mechanical dis- 

 tortions caused by the cutting processes 

 (Dempster, W. T., Anat. Rec, 1942, 84, 

 241-267, ibid, 269-274, Stain Technol. 

 1943, 18, 13-24), the dimensions of the 

 microscopic parts of a section bear no 

 known or at present knowable relation- 

 ship to any of the size or sizes which 

 these parts had in life. 



In the light of the above paragraphs 

 it becomes apparent that microscopic 

 observations of living organized tissues, 

 illuminated by quartz rods or other 

 techniques, makes available certain 

 classes of information not obtainable 



