532 Transactions of the Society. 



Here, then, we have an excellent example of an organism 

 posing as a bacterium, ready perpetuation of its bacilloid and 

 coccoid phases on laboratory media being entirely responsible 

 for our misinterpretation of its true nature. But the point to 

 which I wish particularly to invite your attention is the fact — of 

 general biological interest — that this organism in typhus fever 

 exhibits during its life-history a phase so minute as to be capable 

 of passage through the fine bacterial filters employed, and that 

 this later develops into the full-grown organism which is non- 

 filterable. Moreover, I have the best possible reasons for be- 

 lieving that I shall shortly be able conclusively to demonstrate 

 the same principle at work in cerebrospinal fever, in scarlet fever, 

 in measles, and in the enteric group, and that we are here touch- 

 ing a fundamental law operative also in many other of the infective 

 diseases. 



I wish, however, to make it clear once more that in the 

 photographs Mr. Duncan will show you I am at present claiming 

 nothing conclusive in the case of the typhoid and paratyphoid 

 preparations, which are only shown to-night because they illustrate 

 points in the typhus micro-organism which I am now satisfied 

 is not a bacterium at all," in the sense frequently applied to 

 that term. The films you will see under the microscopes are 

 mostly stained by Gram's method, whilst the photographs are 

 from acid congo-red preparations. This adsorption method, though 

 devised many years ago for botanical work, was independently 

 thought out by my friend and colleague, Dr. Benians, for bacterial 

 work. I have found it, as you will see, of the greatest value in 

 testing the truth of my thesis as to the true botanical position of 

 many of the so-called bacteria, and I feel certain that in the 

 future Dr. Benians' method will largely replace the indian ink 

 method in morphological study. 



Dr. Hort then rapidly outlined the special difficulties to be 

 encountered in the study of films prepared from killed organisms, 

 with special reference to genuine and spurious branching, and 

 to the post-fission movements of " snapping " and " slipping " 

 described by Hill in 1904. He then summarized the evidence 

 afforded by the photographs of genuine sprouting, drawing 

 particular attention to what appeared to be sagittal segmentation 

 as the earliest sign of sjDrouting, and pointed out that " snapping " 

 forms of post-fission movements apparently occurred in the case 

 of all the three types of organism selected for demonstration. 

 And he concluded from this that if Hill was right when he laid 

 it down that " snapping " was peculiar to the Corynebacteria, 

 then the Bacillus typhosus, the B. 'paraty])hosus A and the bacillus 

 of typhus fever were, strictly speaking, not true bacteria, especially 



