Document 15pVmR0qq9pMo3Q8gGvVQrRwE

"FERRUGINOUS BODIES" IN GUINEA PIGS--DAVIS ET Ah Fig 9.-->Smll elastic fiber that hai been phagoc/tpsed by a macro* phage. Ceil cytoplasm immediately surrounding fiber it quite devoid pi cell organelles and probably corresponds to pseudopodial ectoplasm (x 40.000). between any of these structures with the light microscope. Where a mineral fiber is large or pigmented, it may be possible to rule out asbestos as the core, but in many cases this cannot be done. This is especially true of the finest glass fiber which has similar dimensions to asbestos. For this reason electron microscope ex amination is the only reliable method of distinguishing between the various types of mineral core in a sample of ferruginous bodies, and even then differentiation is often only possible if an electron diffrac tion pattern can be obtained from the mineral. Because of these difficulties, it is at present impossible to critically evaluate the finding of ferruginous bodies in mem bers of the normal urban population. It may be that many of these are genuine asbestos bodies, but on the other hand Arch Part--Vot 89, April 1970 8005 US6 PRODUCED BY FORD