192 APPENDIX. 



From the urine itself a great number of bacteria have been 

 obtained, but mostly derived from the air, finding in the urine 

 a suitable soil. A description of uro-bacteria will be found on 

 page 91. 



Micro-organisms of the Blood. Many of the bacteria de- 

 scribed in the body of this book are found in the blood of the 

 animal they infect ; thus, anthrax bacilli are always found in 

 the blood, whereas tubercle bacilli seldom, if ever, enter this 

 secretion. 



When animals are subcutaneously injected with pneumo- 

 cocci they are found in large quantities in the blood. The dis- 

 eases of a hemorrhagic nature affecting fowls and swine usually 

 show the presence of bacteria in the vascular system. 



Bacteria may be recovered from the blood in all forms of 

 septic infection, such as general sepsis, malignant endocarditis, 

 and puerperal sepsis. 



Method of Examination. A drop of blood can be spread on 

 a cover-glass and stained with the ordinary dyes, as sputum, 

 pus, or serum ; but in order to eliminate the coloring matter 

 of the red corpuscles and bring the stained bacteria more 

 prominently into view, Gunther recommends that the blood, 

 after drying and fixing, should be rinsed in a dilute solution 

 of acetic acid (1 to 5 per cent.). The haemoglobin is thereby 

 extracted, and the corpuscles appear then only as faint out- 

 lines. 



Instead of " fixing " by heat, Canon employs alcohol for five 

 minutes, especially in staining for influenza bacilli, which have 

 been detected in the blood. 



This method, however, requires the presence of enormous 

 numbers of bacteria in order to succeed, and the plan com- 

 monly employed consists in making " blood cultures." As 

 large a quantity of blood as possible never less than 10 c.c. 

 is taken from a superficial vein, the median basilic, for ex- 

 ample, by means of a sterile antitoxin syringe, a small incision 

 being made through the skin over the vein in order to avoid 

 skin infection. The blood so obtained is immediately trans- 

 ferred to culture tubes, which are then studied in the custom- 

 arv manner. 



