EEMAKKS ON TECHNIQUE 21 



ing with organisms whose determination is doubtful when examined 

 microscopically. When separating by culture, organisms which are 

 very difficult to differentiate, such a proceeding may assist greatly. It 

 was by such means that Streptotliricice from the canaliculi were first 

 cultivated, and this result was first obtained in my own cases. In 

 aerobic culture the cocci present overgrew everything, before the 

 slowly growing Streptothricite could make any headway. Many 

 facultative aerobic organisms retain their virulence longer in anaerobic 

 culture ; Gifford was thus able to produce a pneumococcal con- 

 junctivitis with a culture which he had cultivated anaerobically. 



Buchner's method is generally sufficient for such anaerobic cultivation : 

 Take a tall glass cylinder with a ground-glass lid, and pour into the bottom of it 

 with a horn or glass spoon about 1 centimetre in depth of pure pyrogalh'c acid ; add 

 to this dilute (30 per cent.) caustic potash or soda solution; and then place the 

 inoculated tube on a small glass tripod in the cylinder ; quickly replace and seal the 

 lid with paraffin or wax. The wool plug should be singed, or a little sublimate 

 poured over it, lest after some time in the damp warmth any spores present in it 

 should work out and contaminate the culture. Cultures deep down in the medium 

 are occasionally useful, and sometimes cultivation in hydrogen by means of the 

 Kipp's apparatus (cf. bacteriological text-books). 



The direct inoculation of an animal with the material to be in- 

 vestigated sometimes results in the isolation of individual forms. An 

 animal injected with sputum will die of pneumocoecal sepsis. For 

 intractable material e.g., concrements from the tear-ducts, tuber- 

 cular matter, and recently in syphilis direct inoculation is indicated. 



The collection of preserved cultures can be very strongly recom- 

 mended, especially for didactic purposes. Such a collection should 

 not only consist of pure cultures, but also of original tubes directly 

 inoculated from secretions, etc. After pouring off the condensed water, 

 1 or 2 drops of pure formol are dropped on to the lowest part of the 

 culture, or the lower end of the wool plug is moistened with formol, 

 and the top is covered for several hours with a rubber cap ; the plug 

 is then removed, and the mouth of the tube fused close. The 

 cultures then remain permanent, and when protected from light 

 retain their colour. 



Inoculation into the Eyes of Animals. 



Schmidt-Eimpler, in his research on the infectiousness of the 

 lacrymal sac secretions, was the first to inoculate the cornea of 

 rabbits or other animals with any organism or material containing 

 bacteria. This is done either by means of an infected needle or knife 

 point, or else by making a small oblique pocket in the cornea (easily 



