TBANSACTIONS OF SECTION D. 749 



(9) Bacillus lams. — This is seen to be a bacillus whose average length is 17 to 

 2-5 /J, and is about five times as long as broad: the ends are distincSy rounded. 

 It occurs singly, in pairs, and occasionally in threads. It forms spores nearly as 

 long as the baciUus itself. It exhibited all the well-known forms of Bacillus 

 subtilis, but on a much smaller scale. It is very motile. It liquefies the gelatine, 

 rendering it turbid, producing a flocculent deposit and forming a tough, greyish,' 

 wrinkled pellicle on the surface. On agar-agar it forms a moist, shining, greyish- 

 white surface-expansion, which grows quickly over the whole agar-an-ar.' It 

 renders the broth at first turbid, but it subsequently becomes clear, a thin"^ granu- 

 lar pellicle forms on the surface, and there is a dirty-white flocculent deposit. The 

 colonies appear as small white dots, which subsequently liquefy the gelatine. Under 

 the microscope the depth colonies have a smooth edge which is irregular in shape. 

 Those on the surface exhibit a very fine thin film, of irregular shape, extendino- 

 from a small centre. " 



(10) Bacillus cereus. — The individual bacilli are from .3'4 /^ to 12 /^ in length ; 

 it also presents thickened forms about 3-4: /i long and V7 n. wide. The ends of 

 the bacUlus are generally slightly rounded, whilst some are quite square. It forms 

 threads which are very variable in length. It also produces spores and is motile. 

 It liquefies the gelatine very rapidly and forms a pellicle ou the surface, and 

 produces a flocculent deposit. On agar-agar it forms a smooth, grey-white, wax- 

 like expansion. It renders the broth turbid, and forms a pellicle oii the surface. 

 The colonies are very characteristic. A\Tien small (under the microscope) they 

 appear as round or oval woolly masses with a finely spinose edge, from which, in 

 many cases^long whip-like and spirally-coiled threads extend into the surrounding 

 gelatine. Sometimes on reaching the sui-face they give rise to highly irregular 

 filamentous gi-o_wths consisting of bands of fine thread. Subsequently the whole 

 plate becomes liquefied. 



(11) Bacillus subtilis. — Under a high power the individual bacilli are seen to 

 vary in length from 1-7 fi to GSfi, whilst in width they are about V? /x ; the ends 

 are slightly rounded, but sometimes nearly rectangular. Prior to spore-formatiou 

 the bacilli become thicker and more square. It forms threads which are frequentlv 

 of great length. It is very motile. It liquefies the gelatine, forming a tough white 

 pellicle on the surface. On agar-agar it rapidly grows over the surface, forming a 

 white opaque expansion, which soon becomes dry and copiously wrinkled. In broth 

 it renders the liquid turbid, giving rise to a white deposit, and forming a pellicle on 

 the surface. It produces colonies of very characteristic appearance, of which only 

 the finely spinose edge colonies have been previously described. In addition it 

 forms what may be called whip-colonies, from the curiously twisted threads, like 

 the lash of a whip, which grow out from a compact centre". Another variety are 

 the meander-colonies, which consist of parallel bands of threads meandering in the 

 most capricious manner over the surface of the gelatine. Subsequently the v.-hole 

 plate becomes liquefied. 



SATUJiDAY, SEPTEMBER 3. 



The following Papers were read : — 



1. Recent Besearches on Earthworms. Bij W. B. Benhaji, D.Sc. 



I. The genera (other than Lumbricus) formed before Perrier 's work in 1872 must 

 be, in most cases discarded, as only external features were noted. Only 

 Iloffmeister's Criodrilus and Schmarda's Perichceta are now retained. 

 II. Perrier described and figured the external and internal anatomy of eleven 

 genera : Anteus, Titanus, Rhinodrilus, Eudrilus, Periowj.v, Biqa'ster, Monili- 

 yaster, TJrochceta, Pontodrilus, Plutellus, Acanthodrilus. But his arrancre- 

 mentof these into Preclitelliani, Intraclitelliara, Postclitelliani, Aclitelliani 

 is now seen to be unnatural. 



