On the Minute Structure of Striped Muscle, fyc. 293 



A paper containing the above results was presented to the Royal 

 Society of London by my kind friend Professor E. Klein, and was 

 printed in the ' Proceedings ' of 1880, and in the ' Quarterly Journal 

 of Microscopical Science,' 1881, and in this paper I ventured to 

 assert that I had been able to explain the appearances generally 

 considered to indicate structural differences -in the course of the 

 fibrils as being due to the varicosity of the fibrils themselves. I 

 further stated that of course structural differences might exist, but 

 that the proof of their existence was not as yet forthcoming. 



My views were received in many quarters with kind consideration, 

 but they were only very partially accepted. For my own part, as 

 soon as I had published them I resolved not to think about the 

 subject again for some years, when, with more matured experience, I 

 might return to its consideration and picking up the threads that I 

 had dropped unravel them with a more skilful hand. 



Recent Investigations with the Collodion Impressions. 



Last winter (1889-90) an idea occurred to me which led once more 

 to my examination of the subject. It struck me that if I could 

 " stamp " some soft transparent solid with muscle fibres it might be 

 possible to obtain impressions of the fibres on the soft material. If 

 these impressions had smooth unstriped depressions corresponding to 

 the fibres, this would indicate that the striping was caused by struc- 

 tural differences within the fibrils ; if, however, the impressions were 

 striated, this could only be explained on the ground that the striation 

 of the "stamp" the muscle was caused by the/orm of the fibrils, 

 which form and which striation were transferred to the soft material 

 in the process of stamping. 



It seemed improbable that I should succeed in getting faithful im- 

 pressions of such microscopic objects, yet I felt that it would be well 

 worth while making the attempt, for the results if obtained would be 

 lost conclusive. I experimented with every substance that I could 

 link of, using wax of various kinds, glass, gelatins, glycerin jelly, 

 transparent soaps, &c. Once or twice I thought that I had obtained 

 rery partial success, but my difficulties were great, for when- 

 ever I hit upon a substance like gelatin, for instance, which would 

 in intimate contact with the fibrils, it invariably came away with 

 lem when they were removed. I worked at the subject for months, 

 rying every expedient which suggested itself to me, and in July, 

 L890, I at last succeeded beyond my most sanguine anticipations. 



It occurred to me that perhaps collodion might be of service, for a 

 thin layer dries quickly and forms a beautifully smooth transparent 

 1m. I accordingly prepared a film by allowing a drop of collodion 

 fall upon a elide, and tilting the slide so that it flowed over it in 



