464 HILDA HEMPL HELLER 



of vibrion-septique were particularly sensitive to the air. Bar- 

 ber found the semi-solid medium of Lignieres excellent for 

 securing growth of single anaerobes. Colonies could be secured 

 from spores in a chamber containing a Pseudomonas pyocyanea 

 culture. 



Malone and Holker have devised pipette methods for single 

 bacillus isolation with which I have no personal experience. It 

 may be that they protect the organisms from air better than does 

 the Barber method. Hecker makes interesting technical 

 suggestions. Hort objects to all methods of single bacillus iso- 

 lation from liquids and he objects to capillary methods on account 

 of optical difficulties. The method preferred by Hort, the perfor- 

 ated plate method, is too aerobic for our purposes. 



IX. Animal inoculation is frequently resorted to for the isolation 

 of anaerobes. The guinea-pig is the best animal for this purpose. 

 It is highly susceptible to infections and also develops very char- 

 acteristic lesions, of diagnostic value. Animal inoculation is of 

 prime value for recovering pathogens that have been badly over- 

 grown. It is the only way I know of to recover blackleg organ- 

 isms that have been grossly contaminated. A drop of lactic acid 

 may be used for a second trial, if the first fails. Inoculation of 

 mixtures from the involved tissues of gas-gangrene cases is of 

 course necessary, but it is likely to give misleading ideas as to the 

 flora of those tissues. It is advisable to run deep-colony cultures 

 from various portions of an amputated limb or of material derived 

 from tissue-puncture or from a blood culture, and to inspect the 

 flora of the limb carefully. A culture or smear from the wound 

 itself may give very misleading data as to the etiology of a gan- 

 grenous process. I believe that the role played by B. Welchii in 

 gas-gangrene nfections has been grossly exaggerated because of 

 the failure of many workers to study carefully the flora from 

 various portions of infected muscle. When the colony method has 

 given pure or apparently pure cultures, inoculate them into guinea- 

 pigs and record results. When immediate identification of patho- 

 gens is urgent, examine smears made by puncture from affected 

 tissue remote from the wound. Conjecture the possible types there 



