100 Mr. W. Gardiner. The Histology of the Cell Wall, 



"The Histology of the Cell Wall, with Special Reference to 

 the Mode of Connexion of Cells. Preliminary Communica- 

 tion/' By Walter Gardiner, M.A., F.R.S., Fellow and 

 Bursar of Clare College, Cambridge. Received August 11, 

 1897. 



Since 1883* I have repeatedly endeavoured to discover some refined 

 and generally applicable method by means of which the fine fibrillar, 

 or "connecting threads," traversing the cell membrane might be 

 identified with certainty, and the fact of their existence settled 

 beyond dispute. I was also anxious to be in a position to investigate 

 the development of the threads in endosperm tissue. My researches 

 met with little encouragement until 1894, when I succeeded in find- 

 ing a new method, by means of which I obtained excellent results 

 with the young developing endosperm tissue of Tamus communis. 

 This I have further elaborated, so that either the original method, or 

 modifications of it, can be applied to tissues generally. In the present 

 communication I propose to give a brief account of my researches, 

 leaving a more detailed description to a future occasion. 



The methods used by earlier observers for the investigation of 

 connecting threads are essentially based upon those of Sachs and of 

 Hanstein, by means of which they demonstrated the characteristic 

 structure of sieve-tubes. Tangl's important results of 1880, which 

 were confirmed and extended by myself in 1883, were in fact 

 obtained by Hanstein's method as such, and are the outcome of 

 quite special conditions, and a happy combination of circumstances, 

 depending upon the fact that in dry ripe seeds the tissue is so poor in 

 water that with the iodine and Schulze's solution (Chlor. Zinc. Iod.), 

 the cellulose fails to give the usual blue colour, and thus allows the 

 darkly stained threads to come into view. The method ceases to 

 work with unripe seeds, or even with ripe seeds which contain a 

 certain percentage of water, and with ordinary tissue is quite useless. 



Certain modifications of the method of Sachs, and the method of 

 Hanstein, which may be described in general terms as involving both 

 a more regulated application of the swelling agents and the use of 

 aniline dyes in place of iodine, were first and independently intro- 

 duced by Russow and myself in the years 1882 and 1883. As regards 

 my own researches, my first results in 1882 were obtained by a modi- 

 fication of Sachs' method, and consisted in swelling sections of fresh 

 tissue with sulphuric acid, and then staining with Hofmann's violet 

 (methyl violet) washed out with glycerine, or with Hofmann's blue 

 dissolved in picric acid (picric Hofmann's blue). This was succeeded 



* Gardiner, ' Roy. Soc. Proc.,' No. 229, 1883. 



