438 PROCEEDINGS OF THE ACADEMY OF [1890. 



filaments. Nevertheless these filaments can be determined beyond 

 a doubt, by a sufficiently high power lens. 



Under these circumstances the speaker believed that the difference 

 between the two species is that of development only. 



Note on Stemoiiitis maxima Sz. — Mr. Wing ate remarked that he 

 had carefully examined the type of this Stemonitis in the Schweintiz 

 collection in the herbarium of the Academy, and although the spec- 

 imen is very old and has not been handled with the care which is 

 now bestowed upon these delicate forms of the Mycetozoa, the speaker 

 was gratified to find a remnant of capillitium which contained spores 

 enough to identify the species with one of the commonest forms 

 found in this vicinity. This very common species will probably be 

 found in most herbaria under thename oi Stemonitis fusca (Roth) Rost. 

 but on comparing it with an authentic specimen of the latter species 

 the distinctness of the two species is very apparent. Mr. J. B. Ellis 

 has sufficient material at present of Stemonitis maxima Sz. and pro- 

 poses to issue it shortly in Ellis & Everhart's " North Amer. Fungi." 

 The speaker was indebted to Mr. Geo. Massee of Kew Gardens, Lou- 

 don, for authentic specimens of several species of Stemonitis, and 

 hoped with this aid to be able to identify our American species and 

 make the same the subject of a future communication. 



December 23. 

 Mr. Chas. p. Perot in the chair. 



Thirty-one persons present. 



A paper entitled " Palaeosyops and Allied Genera," by C. Earle 

 was presented for publication. 



The Development of Bacillus tuberculosis. — Dr. Samuel G. Dixon 

 made the following summary report of his work in the Bacteriolo- 

 gical Laboratory of the Academy with special reference to investi- 

 gations on the tubercle bacillus. The communication was read at 

 the meeting of the 18th ult., publication being deferred in conse- 

 quence of the author's immediate departure for Europe : — 



Our experiments show that the Bacillus tuberculosis is capable of 

 changing from its commonly recognized rod form to that of a more 

 compound one. Some of the rods assume a club shape, while fur- 

 ther on in the cycle of life, they become branched, many organisms 

 showing at least one distinct branch. 



When these forms, including some ordinary shapes, are placed on 

 a pabulum, rich in glycerine and poor in pepton, yet suited to their 

 existence, the culture medium within a few weeks shows an increase 

 of foreign matter. This includes not only a few of the complex 

 forms but many ordinary rod bacilli. Time, however, produces an in- 



