Spiral Structure of Muscle. 85 



tion of corrosive sublimate (solutiou No. 2) of course cannot be 

 employed, as the fibrils become speedily decomposed and indi- 

 stinct. For such preparations the author prefers a solution 

 containing y^^^th of nitrate of silver in distilled water, using this 

 instead of the solution No. 2, but having proceeded as before 

 with the teasing out in solution No. 1. It is true that the ni- 

 trate of silver does not show the spirals with the same remarkable 

 distinctness as the solution No. 2, and besides, the preparation 

 is here and there defaced with a precipitate ; but for prepara- 

 tions to be preserved for any length of time, it is to be preferred. 

 For immediate examination the author especially recommends 

 the solution No. 3. 



The use of chemical reagents having been objected to, it may 

 be replied, as suggested to the author by his brother, J. T. Barry, 

 were anyone denying the existence of the structure in question, 

 then it might be very proper to object, that reagents had de- 

 stroyed it ; but when the existence of that structure is affirmed, 

 it cannot be objected that that structure has arisen through those 

 reagents, especially when, in order to bj-ing it into view, sub- 

 stances so very different have been used, as corrosive sublimate, 

 nitrate of silver, and chromic acid. Least of all can those object 

 to the use of chemical reagents who in such researches employ 

 maceration, which, as is known, does not require much time to 

 produce in organic substance the greatest changes. 



Adhering to his oi-iginal views regarding the situations of the 

 strife in the fasciculus of muscle, as above quoted, the author 

 gives figures illustrative of the same (figs. 4 and 5). These 

 show the situations of the dark longitudinal striae to correspond 

 to the spaces between the edges of the fibrils, and the situations 

 of the dark transverse sti'ise to correspond to the crossing places 

 of the winds of the spirals. It is obvious from the same figures 

 that both the longitudinal and transverse striae are pi'oduced by 

 the refraction of light ; for at the very part where the dark striae 

 present themselves, the rays from the mirror of the microscope 

 fall upon oblique surfaces, where they are diverted from their 

 direct course and do not reach the eye. The dark longitudinal 

 striae are produced by the cylindrical form of the elementary 

 muscular threads, and the dark transverse stria; arise partly from 

 the same cylindrical form of the muscular threads, but chiefly 

 from the oblique direction of the same at their crossing. 



Had observers paid due attention to the history of develop- 

 ment, they could not have failed to observe a pellucid gelatinous 

 substance to which the author has given a name suggested to 

 him by Professor Owen, that of hyaline ; a name descriptive of 

 the appearance only, though the substance evidently performs 



