PLATE XXIII. 



FIG. i. -STREPTOCOCCUS PYOGENES. 



Broth culture of forty-eight hours' growth, incubated at37C., from the pus of one of the 

 subcutaneous abscesses which arose during the course of puerperal septicaemia. 



Carbol fuchsine, washed in dilute acetic acid. The chain on the right hand side of the 

 figure is added from a cover-^lass preparation of the pus of an axillary abscess which showed 

 large numbers of such without any staphylococci. The micro-organism, which is best 

 studied in broth cultures, presents itself as micrococci arranged in chains of varying length. 

 The component elements are almost everywhere Hattened, and occur in pairs, showing that 

 active division is in progress throughout the chain. Here and there elements occur which 

 are oval or elongated in the direction of the chain, and all transitions may be traced between 

 such and the pairs of flattened cocci resulting from their sub-division. Wedge-shaped 

 forms may be met with in adaptation to the pressure arising at sudden bends. At times 

 division of a component co cus takes place in the long axis of the chain, as may be seen in 

 that on the right hand side. This mode of fission may become a source of lateral branching 

 should the process of sub-division continue in parallel planes. 



At times certain of the cocci will divide cross-wise into four. Some of the chains are 

 very slender, and different parts of the same chain may present marked differences in respect 

 of breadth or thickness. 



FIG. 2. BACILLUS OF QUARTER-MVIL, OR SYMPTOMATIC ANTHRAX. 



Cultivation in 2 per cent, glucose broth, incubated at 37 C., of twenty-four hours' growth. 



The organism, like those of malignant oedema and tetanus, is a strict anaerobe, i.e., it 

 grows only in the absence of gaseous oxygen. The culture was grown in an atmosphere of 

 nitrogen by Buchner's method of removing the atmospheric oxygen with pyrogallate of 

 potassium. Carbol fuchsine, washed in water weakly acidulated with acetic acid. 



The growth at this stage consists of rods of varying length produced either into simple 

 or segmented filaments. The elements composing the filaments are by no means of regular 

 length, in consequence of a continuance of their sub-division. 



The breadth is less than that of the anthrax bacillus, and the apposed ends of the segments, 

 in place of being squarely cut (as in the latter ; see preceding volume), are rounded. 



It must be here observed, however, that in the bacillus of anthrax squareness of the 

 apposed ends may be as wanting as in either malignant oedema or quarter-evil. 



At the end of twenty-four hours few sporulating rods were present in the culture. 



By the third day abund ;nt spore-formation had taken place, as is shown in Fig. 3. The 

 preparation consists of straight rods, large numbers of which are sporing. Pairs of rods 

 joined end-to-end are not infrequent. The spore forms, as a rule, at one of the extremities 

 of the rod, which it considerably exceeds in diameter so as to give rise to a drum-stick 

 appearance, much as in the tetanus bacillus, except that the spores are oval in place of 

 being spherical. 



The formation of the spore is first evidenced by a swelling of the end of the rod : in this 

 enlargement the unstained spore subsequently appears. 



This organism is closely like that of malignant cedema both in its cultural characters and 

 its. morphology. In the bacillus of malignant cedema, however, the spores, in place of 

 bsinsr terminal, form towards the centre of the rods. The bacillus of quarter-evil has not 

 yet been identified as a cause of disease in man ; that of malignant redema not infrequently 

 has. 



Stain : Aqueous solution of gentian violet, washed in i in 10,000 solution of caustic potash, 

 followed by tap- water. 



