PROCEEDINGS OF THE SOCIETY. 623 



Mr. Scourfield said he bad not yet had an opportunity of testing 

 the apparatus, but the results Mr. Akeburst had kindly shown him were 

 excellent. The method of immersing the objectives was extremely 

 useful, as it gave a better idea of the solidity of the objects, and 

 permitted one to actually see what was happening when following the 

 free movements of organisms. He hoped this communication would 

 stimulate competent workers to compute immersion lenses for this par- 

 ticular kind of work. 



Mr. Maurice Blood did not think it would prove a difficult matter 

 to have immersion fronts for dry lenses of the powers required if they 

 were lenses of not too wide an angle. The apparatus was a very useful 

 one, and possessed one special advantage : there would be no discussion 

 as to who was the originator of " the tank." 



The President said that, unfortunately, Dr. Charles Singer had been 

 called away on military duty, and so was prevented from giving his paper 

 on '• The Microscopic Work of the Accademia dei Lincei." The paper 

 would, however, be contributed on a future occasion. 



Dr. Hort then made his communication on " Studies in Pleo- 

 morphism in Typhus and other Diseases," illustrated by a number of 

 remarkable photomicrographs prepared and exhibited by Mr. Martin 

 Duncan. The paper is printed m extenso in the Transactions. In the 

 discussion that followed, 



Dr. John Eyre confessed he had no practical experience of the 

 organism associated by Rabinowitsch with typhus, but Dr. Hort's 

 observations on the typhoid bacillus vividly recalled some work carried 

 out fourteen years ago by a then colleague of his at Guy's, Dr. Pakes, on 

 this organism, in which the typhoid bacillus cultivated in nitrate broth 

 exhibited exaggerated pleomorphism, and forms were obtained very 

 similar to those shown by Dr. Hort from the acid broth. At that date 

 dark-ground illumination apparatus had not reached the present pitch of 

 perfection, and neither the indian-ink method or the congo-red method 

 was available. Those observations he referred to were carried out with 

 the ordinary central stop under the condenser. At one time he himself 

 used Rheinberg's colour disks. The interpretation he then placed on 

 the peculiar appearances which Dr. Hort had demonstrated, after obser- 

 vations sometimes prolonged to many consecutive hours, was that the 

 apparent branchings of the typhoid bacillus were not branchings at all, 

 but were organisms crossing each other or lying one on top of the other ; 

 moreover, during the observation period the individual bacilli concerned 

 could be seen gradually slipping one over the other. In reference to 

 another of the appearances which Dr. Hort mentioned — viz. the bean- 

 shaped arrangement, with a groove along its centre, and another with 

 segmentation of its cell protoplasm — similar appearances were shown to 

 the Society a few months ago by Mr. Barnard in " ultra-violet " 

 photographs of the Bacillus hubjarkus. He (the speaker) was not pre- 

 pared at the present moment to agree that this was necessarily sporula- 

 tion, or division of spores, or anything of that kind ; but it was an 

 indication that Dr. Hort was seeing, in some of these pleomorphic 



