514 PATHOGENIC AEROBIC BACILLI 



growth. On potato the growth is sometimes invisible ; on some potatoes a 

 light-brown layer may be developed. Grows well both in Parietti's solution 

 and in Uffelmann's gelatin. 



Pathogenesis. Pathogenic, but in less degree than Bacillus venenosus. 



155. BACILLUS VENENOSUS LIQUEFACIENS. 



Obtained by Vaughan from water. 



Morphology. Bacilli with rounded ends, one and one-half to twice as 

 long as broad. 



Biological Characters. An aerobic and facultative anaerobic, lique- 

 fying, motile bacillus. Spore formation not mentioned. Grows rapidly in 

 the usual culture media at the room temperature also at 38 C. On gehttni 

 plates the deep colonies are finely granular, spherical, and yellowish iu 

 color; superficial colonies elevated and spread over the surface. In gelatin 

 tubes grows abundantly along the line of puncture and spreads slowly over 

 the surface; liquefaction commences in from four to six weeks. On agar a 

 thin, white growth. On potato a moist, light-brown or yellowish growth. 

 When kept for fourteen days or longer on spleen tissue it forms an invisible 

 growth on potato. Grows abundantly both in Parietti's solution and in 

 Uffelmann's gelatin. 



Pathogenesis. Pathogenic for mice, rats, guinea-pigs, and rabbits. 



156. BACILLUS AEROGENES CAPSULATUS. 



Found by Welch in the blood vessels of a patient with thoracic aneurism 

 opening externally ; autopsy made in cool weather eight hours after death 

 the vessels found full of gas bubbles. 



Morphology. Straight or slightly curved bacilli with slightly rounded 

 or sometimes square-cut ends ; a little thicker than Bacillus aiithracis, and 

 varying in length average length 3 to 6 fj. ; long threads and chains are oc- 

 casionally seen. The bacilli, both from cultures and in the animal body, are 

 enclosed in a transparent capsule. 



Biological Characters. An anaerobic, non-motile, non-liquefying ba- 

 cillus. Does not form spores. Grows in the usual culture media, in the ab- 

 sence of oxygen, at the room temperature, and produces an abundant de- 

 velopment of gas in all. In nutrient gelatin there is no marked liquefaction, 

 but the gelatin is slightly peptonized. In agar, colonies are developed which 

 are usually one to two millimetres in diameter, but may attain a diameter of 

 one centimetre ; they are grayish- white in color and in the form of flattened 

 spheres, ovals, or irregular masses, beset with little projections or hair-like 

 processes. Bouillon is rendered diffusely cloudy, with an abundant white 

 sediment. Milk is coagulated in one or two days. The cultures in agar and 

 bouillon have a faint odor, comparable to that of stale glue. Upon potato & 

 pale grayish-white layer is developed; growth occurs at 18 to 20 C., but is 

 much more rapid at 30 to 37 C. Bouillon cultures are sterilized by ex- 

 posure to a temperature of 58 C. for ten minutes. 



Pathogenesis. "Quantities up to 2.5 cubic centimetres of fresh bouillon 

 cultures were injected into the circulation of rabbits without an y apparent 

 effect, except in one instance in which a pregnant rabbit was killed, by the 

 injection or one cubic centimetre, in twenty -one hours. If the animal is 

 killed shortly after the iniection the bacilli develop rapidly after death, with 

 an abundant formation of gas in the blood vessels and organs, especially t lie 

 liver. At temperatures of 18 to 20 J C. the vessels, organs, and serous cavi- 

 ties may be full of gas in eighteen to twenty-four hours, and at tempera- 

 tures or 30 to 32 C. in four to six hours, when one cubic centimetre of a 

 bouillon culture has been injected into the circulation shortly before death." 



It is suggested by Welch and Nuttall that in some of the cases in 

 which death has been attributed to the entrance of air into the veins, the gas 



