PRACTICAL HISTOLOGY FOR MEDICAL STUDENTS. 19 



ratures. a. Carmine injection (Carter's receipt). (See Beale, 

 * How to Work.') h. Blue injection (Ludwig's). Solution 

 A. Gelatine, 50 parts ; distilled water, J200 parts. Dissolve 

 with the aid of a gentle heat. Solution b. Soluble Prussian 

 blue, 4 parts ; distilled water, 200 parts. Dissolve ; add 

 solution B to solution a gradually. All Prussian blue injec- 

 tions must not come near any alkali. The blood-vessels may 

 be injected immediately after death, or after the rigor mortis 

 has passed off. In the former case paralyse vaso-motor 

 nerves by a blow on the head, or, if possible, section of the 

 cervical spinal cord. After the latter beware of extrava- 

 sation. 



B, Bile-ducts; use soluble Prussian blue, with or without 

 gelatine. 



c. Lymphatics ; watery solution of soluble Prussian blue 

 most useful. The best demonstration of injected lymphatics is 

 obtained from the testis of the dog. Take a Wood's syringe and 

 thrust the nozzle through the tunica albuginea; inject the fluid 

 slowly. It finds its way into the lymphatics readily. The 

 thoracic duct may even be injected from this source. The 

 lymphatics of aponeurosis may be injected in this Avay also 

 (Ludwig). For other injections generally, abandon the syringe 

 and use Wolff's bottles, with water pressure. Indicate 

 the amount of pressure by means of a mercurial manometer. 

 I arrange the apparatus in this way : — a, A large jar of water 

 attached to a pulley, so that it can be elevated to any height. 

 A long elastic tube with a stopcock is connected with the 

 interior of the jar near its bottom, so that the water may flow 

 out when required. The other end of this tube transmits 

 the water into h, a lai'ge Wolff's bottle, having three aper- 

 tures. The bottle contains air at the commencement. The 

 water is permitted to flow in by one aperture, through along 

 glass tube which passes to the bottom of the bottle. The air 

 is thereby driven out through the other two apertures, one 

 communicating with (c) a mercurial manometer for indicating 

 the pressure, the other transmitting the air through an elastic 

 tube to f/, a second Wolff's bottle containing the injecting 

 fluid. This bottle has tAvo apertures. The air is forced upon 

 the surface of the fluid, and a glass tube, reaching nearly to 

 the bottom of the bottle, transmits the fluid thence to an elastic 

 tube joined to a glass or metal nozzle placed in the artery. 

 Any number of Wolff's bottles corresponding to (f/) may be 

 added, so that different injecting fluids can be thrown in 

 at the same time. The pressure can be regulated with* 

 the greatest nicety. There is no jerking, no refilling of 



