GAERTNER GROUP 161 



The medium is sterilised imder pressure either in bulk or in 

 10 c.cm. quantities in tubes. The briUiant green (Hochst) is 

 kept as a stock 1 per cent solution which is made into a 1 in 

 10,000 solution just before use by diluting 0.1 c.cm. to 10 c.cms. 

 Before inoculating the 10 c.cms. of peptone saline medimn with 

 the suspected material, 0.5 c.cm. of the 1 in 10,000 brilHant green 

 solution is added. The tubes are incubated at 37° C. for twenty 

 to twenty-four hom-s and then plated out on neutral red bile salt 

 agar or Endo's medium, preferably the former. The coloiuless 

 characteristic colonies are fished and put through the usual 

 agglutination and biochemical tests. Using this method, the 

 author has been able to isolate B. typhosus from the sediment of 

 nulk to which had been added 23 typhoid baciUi per 100 c.cms. 



Paratyphoid-enteritidis or Gaertner Group. The organisms 

 of this group may be isolated by the same method as is given 

 above for B. typhosus or, if no examination is required for B. 

 typhosus, the sediment and cream may be inoculated into meat 

 peptone dextrose broth (neutral to phenolphthalein) containing 

 0.15 c.cm. of a 1 per cent solution of briUiant green per 10 c.cms. 

 of broth. (Tonney.2°) This strength of brUhant green (1 in 

 6600) inhibits the growth of the Escherich and Eberth groups, 

 and enables the Gaertner group to predominate the broth cul- 

 tures. The broth cultures are subsequently plated out on 

 neutral red lactose bUe salt agar and the non-lactose f ermenters 

 worked out in the usual way. 



Morgan's Bacillus No. i. During the last few years the 

 attention of sanitarians has been directed to the etiological 

 relationship between milk supplies and epidemic srnnmer 

 diarrhoea. It has been evident for many years that artificial 

 feeding of infants was a contributing factor but no definite 

 cause was assigned for this phenomenon. Defective feeding has, 

 no doubt, contributed to the excessive infantile mortahty that 

 occurs each summer, but there is a rapidly accumulating mass 

 of evidence that the epidemic variety of summer diarrhoea is 

 primarily or secondarily dependent upon the activity of micro- 

 organisms. The substitution of a clean milk supply or the 



