250 LABORATORY EXERCISES IN BACTERIOLOGY. 



(facultative and obligate) that the method is of value. It is the practice of the writer 

 to prepare a number of capillary tubes, inclosing them in a large glass tube like that 

 used in Hesse's air apparatus, both ends of which are filled with cotton plugs. In 

 this they are sterilized in the oven and kept until used. When filled with an inoculated 

 medium and closed, each capillary is marked with the wax pencil so that it may be 

 surely distinguished and placed for culture in a second sterile glass tube like the first 

 in order to prevent the outside surface of the capillary from contamination and to 

 allow observation during culture. It will be found convenient to attach to this con- 

 taining tube a strip of card or paper on which may be marked the time and appearance 

 of each colony for each of the contained capillaries as it appears, as is indicated in the 

 accompanying diagram (Fig. 67). Several capillaries may be kept in the enveloping 

 tube if properly marked to prevent confusion. When growth appears in such a capil- 

 lary at any distance from the ends, whether the ends have been sealed or not, it may 

 be accepted as either a facultative or obligate anaerobic colony; when the tube is 

 sealed, all growth appearing is anaerobic; should the ends not be sealed and growth 

 occur close to the end, it may, however, be an aerobic variety. 



When it is desired to transfer the colonies to separate culture tubes, a capillary 

 is withdrawn from the large container and with a sterile forceps a short length bearing 



*fi-/6-0? white. round, finely granular, margins c/'//' 



_ - ._ white XT" 

 ovo'd glistening 



FIG. 67. SALOMONSEN'S CAPILLARY TUBES INCLOSED IN PROTECTIVE GLASS TUBE, WITH 

 LATTER ATTACHED TO CARD ON WHICH ARE PRESERVED NOTES OF COLONIES 

 WITHIN. 



the colony broken out (one end of the fragment should be very close to the colony) 

 and dropped into sterile medium. (It is well first to transfer to bouillon into which 

 diffusion from the colony in the capillary fragment readily takes place; after growth 

 in the bouillon one or two loopfuls are smeared over the surface, or a stab made wdth 

 the straight needle into the interior of fresh solid medium.) The medium inoculated 

 with the colony from the fragment of the capillary tube should for several days be 

 grown in the anaerobic jar, its growths transplanted, and the medium then exposed 

 for some days to the ordinary atmosphere in order to afford a chance of development 

 to any aerobic individuals which possibly may be present. 



This method is especially valuable in isolation of the anaerobes, facultative or 

 obligate, in studies of blood or other pathologic material taken from some diseased 

 individual, such a fluid being drawn directly into the capillary tube and sealed therein, 

 where it serves as the culture medium for the preliminary growth (McLaughlin). 



Exercise 72. A tube of liquefied gelatine is inoculated with a loopful 

 each of a bouillon culture of Bacillus typhosus and Pseudomonas pyocyanea. 

 Let each student recover in pure culture and present for inspection the 

 former of these organisms by the above method.. 



