FROM DEAD TISSUES. Itg 



(a.) Blood. — In the human subject this should be taken as soon 

 after death as possible, by sterilising a portion of the skin, as already 

 described, and introducing the sterile needle of a Pravaz' syringe 

 into a vein from which the blood is withdrawn. This blood can be 

 at once inoculated into various media, and the cultivation of its con- 

 tained organisms at once proceeded with. In animals the peri- 

 cardium is laid open with a sterile knife and forceps, and the left 

 ventricle opened with sterile scissors ; and then a sterile platinum 

 wire is introduced into its cavity^ and some of the blood removed for 

 inoculation. 



(b.) Tissues. — In the human subject either a dissection is made 

 with sterile instruments immediately after death, or a harpoon is em- 

 ployed, as described under living tissues, and a small portion of tissue 

 obtained in either of these ways is planted in a nutrient soil, as already 

 detailed. In animals small portions of tissue are separated by dissec- 

 tion, removed with a sterile platinum wire, and forthwith implanted 

 in a nutrient soil. 



In the case of the tubercle bacillus a pure cultivation was first ob- 

 tained by pounding down a caseous bronchial gland in boiled dis- 

 tilled water, and planting the extract thus obtained in blood serum. ^ 



(c.) Discharges. — It is difficult to obtain pure cultivations of micro- 

 organisms from discharges collected after death, as the post mortem 

 contaminants are usually both numerous and varied. If the attempt 

 be made, some of the discharge should be diluted with boiled dis- 

 tilled water, and then allowed to trickle in a thin layer over the sur- 

 face of solid nutrient media (potatoes, gelatine), and the various foci 

 of growth which result may then be separately examined, and any of 

 special interest separated, and cultivated apart in sterile media. 



* Vide Koch, op. cil. 



