C. L. HOAGLAND 



more challenge to the clinician than progressive muscular dystrophy. 

 This disease, first clearly described by Gowers (6), is characterized by 

 primary degeneration and atrophy of voluntary muscles of the ex- 

 tremities, pelvis, and shoulder girdles. Atrophy is marked in all 

 forms, and hypertrophy or pseudohypertrophy is an early and promi- 

 nent symptom in one form. The disease has certain well-established 

 familial aspects, although the mode of genetic transmission is not 

 always clear. In the most common type, pseudohypertrophic mus- 

 cular dystrophy, the onset usually occurs before the fifth or sixth year. 

 The prognosis is grave, and death frequently results within several 

 years after the disease has become clearly manifest. No specific 

 therapy for the syndrome is known and little in the way of supportive 

 therapy has proved useful (16). 



Morphological studies on progressive muscular dystrophy have 

 yielded little information, aside from the fact that there is hyaline 

 degeneration and fragmentation of muscle fibrils, and that the muscles 

 show marked increase in fat content. The recent development of a 

 simplified quartz microscope, with the 2537 A. line of mercury as the 

 light source, has made it possible to obtain ultraviolet photomicro- 

 graphs of muscle fixed and sectioned by current methods, and in cer- 

 tain instances on surviving specimens without previous fixation (8). 

 Photomicrographs of muscle made by this technique show selective 

 absorption of varying intensity, and reveal more detail than those 

 obtained with visible light on stained material. The technique has 

 particular advantages in the study of muscle when it is desired to 

 correlate morphological and physiological changes. In ordinary light 

 the appearance of unstained muscle is misleading, since the image 

 under these conditions is due to inhomogeneity of tissue and not to 

 the presence of material with selective absorption. 



Description of the histological and pathological changes re- 

 vealed by ultraviolet light is difficult at the moment, because of the 

 inappropriateness of classical nomenclature for description of images 

 produced by specific absorption of light rather than by staining and 

 physical inhomogeneity of tissues. Certain analogies can be drawn, 

 however, between structures photographed in ultraviolet light and 

 those structures which are seen in visible light as a result of the appli- 

 cation of tissue stains, on the basis of size and location of the structures 

 within a given cell. It is evident from these studies that ultraviolet 



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