JEHANGIR FARDUNJI DASTUR. 211 



chloric acid and caustic potash, which is not dissolved by acids, 

 alkali carbonates or ammonia, which stains red with Ruthenium red, 

 violet with alum hematoxylin, ' and brown with acidified Bismark 

 brown," the stain being not washed out by acids and alcohol, is 

 presumably some compound pectic substance. 



The stalk of the oogonium within the antheridium undergoes 

 the same modification as the fertilised oogonium, though not to 

 such a great extent as the latter. This stalk occasionally has a 

 cellulose plug like those found in vegetative hyphse. 



The composition of the walls of the oospore could not be accu- 

 rately determined. But the outer wall appears to be composed 

 of some compound pectic substance and the inner wall of cellulose ; 

 because the solvents of the outer wall of the oogonium dissolved 

 the outer wall of the oospore and the undissolved part of it gave 

 all the reactions of cellulose ; because strong sulphuric acid did not 

 dissolve the outer wall of the oospore ; again when the oogonium 

 was allowed to be acted upon either by weak solutions of its 

 solvents or by strong solutions for an insufficiently short time the 

 enclosed oospore when treated with the iodide reagents of cellulose 

 stained yellow on the outside and blue in the interior. 



During this work I have found chlor-zinc-iodide and iodine 

 and sulphuric acid, commonly used for staining cellulose, to be very 

 unsatisfactory as their action is capricious, but calcium-chloride- 

 iodide and iodine and phosphoric acid recommended by Mangin 

 have given excellent results, especially the latter ; with its use the 

 intensity of the stain can be easily regulated by the use of different 

 strengths of iodine solution and the stained slides have been found 

 to keep well for over two months. 



Media. 



French-bean (Phaseohts vulgaris) juice agar and oat juice agar 

 have pi'oved to be the best media. These two media have been 



1 .Mangin, L. Sur a constitution de la membrane dea vegetaux, C. R., CVII, 1888, p. 145. 



2 Ibid., Sur la presence des composes peetiques dans les vegetaux, C. R., CIX, 1889, 

 p. 580. 



