. The principles of bacteriology: a practical manual for students and physicians. slowness with which itliquefies gelatin and by the comparative absence ofpathogenic properties ^hen injected into the circulationof rabbits. Welch regards this organism as a varietyof staphylococcus pyogenes albus. Streptococcus Pyogenes. — From a spreadingphlegmonous inflammation prepare cover-slips and cult-ures. What is the predominating organism ? Does itappear in the form of regular clusters like those ofgrapes, or have its individuals a definite, regular ar-rangement ? (See Fig. 56.) Are its colonies like t
. The principles of bacteriology: a practical manual for students and physicians. slowness with which itliquefies gelatin and by the comparative absence ofpathogenic properties ^hen injected into the circulationof rabbits. Welch regards this organism as a varietyof staphylococcus pyogenes albus. Streptococcus Pyogenes. — From a spreadingphlegmonous inflammation prepare cover-slips and cult-ures. What is the predominating organism ? Does itappear in the form of regular clusters like those ofgrapes, or have its individuals a definite, regular ar-rangement ? (See Fig. 56.) Are its colonies like thoseof staphylococcus pyogenes aureus? Isolate this organism in pure cultures. In these cult-ures it will be found on microscopic examination to presentan arrangement somewhat like a chain of beads. (Fig. 57.) Determine its peculiarities and describe them accu-rately. They should be as follows; 280 BA CTERIOLOG Y. Upon microscopic examination a micrococcus shouldbe found, but differing in its arrangement from thestaphylococci iust described. The single cells are not Fig. ^J* »• .Hr .^^ i .V / Streptococcus pyogenes iu pus. scattered irregularly or arranged in clumps similar tobunches of grapes, but are joined together in chains likestrands of beads. These strands are sometimes regularin the arrangement and size of the individual cells com- FiG. 57. Streptococcus pyogenes. posing them, but more commonly certain irregular groupsmay be seen in them. Here they appear as if two orthree cells had fused together to form a link, so to speak,in the chain, that Is somewhat longer than the remaining LESS COMMON PYOGENIC ORGANISMS 281 links; again, portions of the chain may be thinner than therest, or it may appear broken or ragged. Commonly theindividuals comprising this chain of cocci are not round,but ajjpear flattened on the sides adjacent to one chains are sometimes short, consisting of four to sixcells; or, again, they may be much longer, and extend froma half t
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