254 DR. G. THIN. 



The object of these manoeuvres was to stain the nuclei and, 

 if possible, the cells in the substance of the fibre without 

 subjecting them to the destructive influence of watery solu- 

 tions. I had already at that time acquired the conviction 

 which has been since much strengthened, that one reason 

 why the delicate flat cells in the tissues have not been seen is 

 that they do not resist the action of water or alcohol. 



The muscular fibres so stained showed many nuclei, a 

 greater number than I had seen by any other mode of pre- 

 paration except that by warm saturated solution of caustic 

 potash. But I was foiled in endeavouring to obtain by this 

 method preparations showing more than the existence of a 

 great number of nuclei on account of the difficulties presented 

 to manipulation by the sarcolemma, and I came to look on the 

 sarcolemma as a great obstacle in the way of a better knowledge 

 of the structure of muscle. That obstacle has, however, 

 been now overcome. 



Amongst the stained fibres one of the preparations was 

 preserved on account of its beauty and the number of stained 

 nuclei. It consisted of several fibres teased so that their re- 

 lation to each other was no longer observable. It was stained 

 and mounted in May, 1874. In August, 1875, the logwood 

 staining had become diff'used, the nuclei being obscured, 

 the preparation consisting of a number of deep blue 

 fibres, uniformly coloured, in which the individual elements 

 could not be distinctly observed. The cover glass was care- 

 fully removed and a large drop of pure glycerine was placed 

 over the fibres. A cover glass was not put on, but the prepa- 

 ration Avas sheltered from dust and laid aside. In February, 

 1876, I teased the fibres. The change effected by the long 

 maceration was at once evident. I found that each fibre could 

 be split into three or four divisions, which were so easily 

 separated from each other that when the end of a fibre was 

 fixed on one side by a needle and on the other side by 

 another needle, it was only necessary to separate the needles 

 from each other, the points being kept fixed, to cleave the 

 entire fibre. When the cleaving was observed under a 

 dissecting lens it was seen to take place so uniformly and 

 evenly that it became evident that it followed a course deter- 

 mined by a structural pecularity of the fibre. One of the 

 parts into which a fibre could be thus divided usually cor- 

 responded in breadth or diameter to that component part of 

 a fibre which I had, when seen indicated in gold prepara- 

 tions, designated a secondary bundle, and I shall for the sake 

 of distinctness apply that term to it in this paper. 



A secondary bundle was sufficiently transparent to show 



