EXAMINATION BY CULTURAL METHODS 167 



desired may be obtained by making gentle suction, either by 

 applying the mouth directly to the end of the tube where it is 

 stopped with cotton, or through the medium of a small piece of 

 rubber tubing slipped over it. 



" By the above instrument vein punctures have been made in 

 about 150 cases of a variety of diseases. At no time was any diffi- 

 culty experienced in obtaining the amount of blood desired, which 

 was generally about i c.c. In a few instances it was necessary to 

 try two punctures before securing a free flow through the needle ; 

 in no case was there any local reaction whatever at the seat of 

 puncture, nor did the patient complain of pain and annoyance." 



I used this method for years, and found it by far the best for 

 clinical work. The needle I employ is made for me by Down, 

 and differs somewhat from that illustrated in being expanded in 

 the middle, so as to hold rather more than 10 c.c, and is graduated 

 in cubic centimetres. It is kept in a wide test-tube plugged with 

 cotton-wool, the whole being sterilized by dry air, so that no time 

 is wasted in boiling it, and the whole process may be performed 

 in five or ten minutes. The main disadvantage is that it requires 

 a special instrument, whereas an all-glass exploring syringe 

 should be always available. 



The advisability of employing some such method in which 

 the blood is drawn directly from a vein in place of the simple 

 skin puncture is very apparent from the researches of Kuhnau 

 {Zeitschrift f. Hyg. und Infct., 1890), who made parallel series of 

 experiments by the two methods. He found that in cases in 

 which the blood drawn directly from the vein remained sterile 

 growth (mostly streptococci or staphylococci) occurred in as many 

 as 90 per cent, of cultures inoculated from skin punctures, though 

 the most careful antiseptic precautions were used. 



The cultures thus obtained are incubated at the body tempera- 

 ture, and examined from day to day. The blood in the broth 

 tube will coagulate, and the appearance of growth may be delayed 

 by the entanglement of the colonies in the clot ; sooner or later, 

 however, the clear fluid will become turbid if bacteria are present, 

 and subcultures can be made on agar or blood-serum, and films 

 examined. 



If colonies appear on the agar tube, they are to be carefully 

 examined with a lens, and their characters noticed. The 

 organisms which will be most likely to develop are streptococci, 

 staphylococci, anthrax bacilli, pneumococci, typhoid bacilli, the 



