X-KAY mk:iu)scopy 



were made in which microradiography was 

 used as a principal or partial method of 

 examination, as well as many other publica- 

 tions appeared on the subject of microradio- 

 graphical technique. 



A new method of microradiography (al- 

 pharadiography) was described by Belanger 

 (122) in which the author used Polonium 210 

 as a source of alpha particles. A histological 

 slide is put on a fine-grain emulsion plate or 

 film and both are placed in a camera obscura 

 on the distance from 20 to 30 mm. After 

 exposure from 4 hours to 4 days, the obtained 

 alpharadiograph may be studied under the 

 microscope as a usual micro radiograph. The 

 author showed several demonstrative alpha- 

 radiographs he made with this method. 

 There is no doubt that this method will 

 contribute to the medical research in the 

 near future. 



Bergandall and Engfeldt (123) described 

 a review of various methods of preparing 

 material for microradiography. They have 

 especially elaborated methods of bone grind- 

 ing, embedding, etc. Several critical remarks 

 are made on x-ray projection microscopy. 

 Some valuable suggestions for the prepara- 

 tion of imdecalcified bone for microradiog- 

 raphy was made by Pugh and Savchuk (137). 



Vincent (113), Engfeldt (48) demonstrated 

 the stratification of fine-fibered bone in mi- 

 croradiographs but did not give morpho- 

 logical explanation to this phenomenon. 

 Bohatirchuk reported results of his micro- 

 radiographic studies on the reversibility of 

 atrophic process in aging bones to the IVth 

 and Vth Gerontological Congress (127) 

 (128). He showed in the first report that 

 certain signs indicate that the calcium 

 impoverishment of aging bones is to some 

 extent a reversible process. Experimental 

 results reported to the ^^th Congress showed 

 that the bone resorption and bone restitution 

 proceed in aging humans and in rabbits 

 along the same morphological lines, and that 

 the experimental bone atrophy is also a 

 reversible process. 



Bohatirchuk (unpublished) made experi- 

 ments with various bone fixatives used by 

 some authors. Microradiographs show almost 

 the complete decalcification of bone by 

 osmium buffered with veronal up to 7.3 pH 

 during 12 hours of fixation (Scott and Pease) 

 (141). Despite some impregnation of bone 

 and soft tissue by osmium, there is almost 

 no absorption of X-rays typical when cal- 

 cium is present in bone (Fig. 22). The same 

 decalcification may be found after fixation 

 with 30% glacial acetic acid after 4 hours 

 fixation. Both these fixatives were used by 

 some electron microscopists who claimed 

 that they have studied the "undecalcified" 

 bone. The advice given to electron microsco- 

 pists and microradiographists is: before using 

 bone for study, check its calcium content via 

 microradiography. 



Vascularisation of bone was the subject of 

 microradiographic studies of Brookes (129) 

 (130). Apparently this author has been the 

 first who clearly demonstrated in his precise 

 radiographs the large capillary bed in the 

 rat bone proper under the normal and 

 pathological conditions. Carreto (131), 

 Trueta et al (143) and Vincent (145) studied 

 partly via microradiography the calcification 

 of bone organic matrix in endochondral type 

 of growth. Trueta et al yet once more em- 

 phasized the role of giant cartilage cells and 

 vessels in the process of calcification. 



Two new contributions were made on the 

 mass determination of cells by Grampp et al 

 (13()) and Rosengren (140) obtained by 

 reference system of Engstrom mentioned 

 above. Findings are in agreement with works 

 on this subject previously cited. 



Lagergren et al presented in two \\orks 

 (136) (137) microangiographical patterns of 

 the inflammatory hypervascularity and 

 those of fibromatous and fibrosarcomatous 

 tumors. In the latter work authors point 

 out the connection between malignanc}^ of 

 the tumor and its vascularity: according to 

 their findings, the more vascular the more 

 malignant. Amprino (117), (118), Strandh 



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