614 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Caloplaca citrina.* — The autonomy and systematic position of this 

 crustaceous lichen has been discussed by Carlo Zanfrognini. He cites 

 the opinion of systematic authorities as -to its relation to Caloplaca 

 murorum, of which it is considered to be a leprose form by many 

 lichenologists. Zanfrognini has himself studied the lichen aud has 

 concluded that it is an autonomous species ; it is always granular in 

 every variety of habitat and differs in internal structure from the lobate 

 ( 'alo'placacese. He contrasts with it other somewhat similar species, 

 C. murorum, G. cirrochroa and G. medians. 



Schizophyta. 

 Schizomycetes. 



Bacterial Flora of the Normal Mouth.f — Z. A. Brailovsky- 

 Lounkevitch has conducted an exhaustive research having for its object 

 the investigation of the normal buccal flora at various periods of life. 



Among children, soon after birth or in the first few hours of life, the 

 mouth cavity was found to be completely sterile, but after the lapse of 

 several hours the mouth becomes rapidly populated with bacteria. The 

 prevailing species observed was Streptococcus salivarius and its varieties, 

 which was always present in smear preparations in the form of scattered 

 diplococci. Other organisms commonly present were Staphylococcus 

 albus, the pneumococcus, Streptococcus pyogenes, B. coli and B. bifidus, 

 but these organisms were regarded as accidental saprophytes. The 

 normal flora in the early period of life is aerobic, or facultative anaerobic, 

 a strict anaerobe such as Parvulus rarely making its appearance. 



With the eruption of the teeth the buccal flora changes in character, 

 and numerous strict anaerobes are 'added to the characteristic flora of 

 the newly born. The anaerobes most commonly observed were Lepto- 

 thrix buccalis, spirochetes, spirilla, vibrios, Parvulus, and B. anaerobius 

 gracilis. From this time onward no essential change in the buccal flora 

 is observed. The various organisms isolated appeared to have a predilec- 

 tion for certain situations — for example, facultative or strict anaerobes 

 were most frequently found on the tongue (where they doubtless found 

 conditions more favourable to growth than on the surfaces of the cheeks 

 or palate), whilst diplococci were most in evidence on the cheeks, palate 

 and tonsils. A marked resemblance was observed in the flora from 

 corresponding regions of the various healthy mouths examined. 



True proteolytic anaerobes were not met with in normal healthy 

 mouths, and pathogenic species of bacteria, when they occurred, were 

 found to be in a state of attenuated virulence. 



Resistance to Chemical Agents of Certain Strains of Bacillus 

 subtilis.} — M. P. Portier has isolated from the larva of Tenebrio molitor 

 (Coleoptera), and the larva of Myelois Gribrella (Lepidiptera), a bacillus 



* La Nuova Notar., xxvi. (1915) pp. 155-65. 

 t Ann. Inst. Pasteur, xxix. (1915) pp. 379-404. 

 X Comptes Rendus, clxi. (1915) pp. 397-99. 



