The Water-binding of the Optic Nerve and of Its Sheaths.

correspond in every way to the 'typical' form; they differ, however, in their action on some of the other carbohydrates. Much controversy has arisen as to the part played by B. granulosis in the aetiology of trachoma; moreover, other microorganisms have been isolated and put forward as aetiological factors. Again, various authors have maintained that the condition is due to a virus, to diet deficiency and lastly that it is an expression of allergy. With these views, however, this paper is not concerned. In our introductory remarks it was clearly indicated that considerable divergence existed in the results of those authors who had carried out work along lines similar to that of Noguchi and our investigation was undertaken merely to ascertain whether B. granulosis was present or not in cases of trachoma occurring in Glasgow. We suggest that some of the discrepancies in the results obtained by various workers have been due to their not having allowed sufficient time for growth to have progressed to the extent of producing visible 'colonies' before pronouncing that the microorganism in question was not present in the material examined. Again, some of these investigators may not have been conversant with the inhibiting action of cocaine on the growth of B. granulosis. Lastly, the importance of immediate inoculation of the media, the keeping of the inoculated plates at room temperature and of maintaining a sufficiently moist surface should be emphasised.