162 TECHNOLOGY OF BACTERIA. 



sealing the capillary extremities in the flame of an 

 alcohol lamp while the tube was still quite hot. 

 Both extremities are sealed as expeditiously as 

 possible as soon as the tube is withdrawn from the 

 vessel. It is evident that to obtain a larger quan- 

 tity of blood, a flask having two necks bent at a 

 right angle and drawn out to form capillary tubes 

 may be substituted for the simple straight glass 

 tube. (See Fig. 1.) 



Fig. 1. 



The color of the blood, due to the presence of 

 the red corpuscles, and the fact that these ele- 

 ments, after a time, form a granular debris which 

 might interfere with the recognition of minute 

 micrococci, are objections to the use of this 

 fluid in culture experiments. Blood-serum, how- 

 ever, is free from these objections, and is a valua- 

 ble culture-medium. This may be obtained from 

 a flask, like that shown in Fig. 1, by transferring 

 the serum, after it has separated from the clot, to 

 small culture-flasks like those described on page 

 179 (Fig. 5), by the method there detailed. To 

 accomplish this, one of the arms of the larger 

 flask is broken off to admit the capillary extrem- 

 ity of the smaller one. By skilful manipulation 

 a number of these may be filled with transparent 



