X-RAY MICKOSCOPY 



Fig. 17. MRD of cats spinal cord, PM thoro- 

 trast coloring, 10/i, approx. X20. The selective ab- 

 sorption of thorotrast by the white matter and 

 fibers is shown. 



esses bccomo visible while us a rule nuclei 

 (like nuclei of other kinds of cells) arc 

 not conspicuous. Sometimes, however, some 

 x-ray absorbinjj; inclusions arc seen within 

 nucleus, e.g., nucleolus. Fibers with opatiue 

 myelin sheaths are colored almost always 

 and may sometimes be followed in micro- 

 radiographs up to the periphery of the sec- 

 tion. Fibrous network in neuroglia adsorbs 

 thorotrast as do some glia cell elements. 

 White matter generally adsorbs more thoro- 

 trast than gray matter (Fig. 17, 18). Not 

 much is known about selective coloring of 

 other normal tissues besides the few facts 

 pointed out above. 



Only one work was published on the prac- 

 tical application of this method in patholog- 



studied in the normal as well as the patholog- 

 ical. 



Indirect Vital Coloring with OM of Tissues 

 Low in Absorbing X-rays. Although Gobi 

 (70), Dauvillier (42) and Lamarque (82) 

 suggested the possibility of indirect x-ray 

 contrasting of organs and tissues via the 

 blood stream, the first practical application 

 of microradiography for this purpose was 

 made by Bohatirchuk (1940) (22) who pro- 

 posed the injection of thorotrast as a test to 

 determine the function of RES. The idea of 

 the test was that in case of stimulation or 

 blockade of RES the adsorption of thorotrast 

 has to be respectively accelerated or delayed 

 and macroradiographs as well as microradio- 

 graphs had to confirm this assumption. Al- 

 though both acceleration and delay of x-ray 

 opacity of organs and cells of RES was found 

 in some experiments, they were discontinued 

 due to the outbreak of war and were not 

 renewed again. 



Post Mortem Coloring with OM of Tissues 

 Low in Absorbing X-rays. As mentioned 

 above, sections of the cat's spinal cord after 

 coloring with thorotrast show in microradio- 

 graphs selective x-ray absorption. The am- 

 photeric cytoplasm of typical motor cells of 

 the ventral horn, cell membrane and proc- 



FiG. 18. Microphotograph of a frontal part of 

 the anterior horn of MRD No. 17 at the higher 

 magnification (approx. X 180) . The selective thoro- 

 trast absorption nervous in cells, fibers and glia 

 elements is shown. In the right upper part of the 

 microphotograph a large neuron with several 

 dendrites is conspicuous. Note some inclusions 

 within the dark nucleus which selectively absorb 

 thorotrast (similar inclusions are seen also in other 

 nuclei). The origin of these inclusions is not clear 

 as yet. 



616 



