108 JAMAICA DOGWOOD. 



this part of the bark, hence its name liber layer. On a cross section 

 (see fig. i, B) 'these fibres are composed of hexagonal cells with very 

 thick walls, having only a spot or a central line for an opening. On 

 a longitudinal section the fibres are frequently i-io of an inch in 

 length. These long cells of the liber fibre give the fibrous 

 structure to the inside of the bark. On either side of the bundles 

 of liber fibre are rows of polyhedral crystals of calcium oxalate. 



Medullary rays, composed of regular brick-shaped cells similar 

 to those of the cork, are seen travesing this layer. This part of the 

 bark contains, besides the liber and crystals of calcium oxalate, 

 some oil ducts and resin glands, apparently different in no respect 

 from the surrounding cells, some small scattered laticiferous tissue 

 and separate oil drops. 



Physiological Action. It is said to be a "cerebro-spinal drug, 

 expending its influence almost entirely upon the nervous system. It 

 causes at first an increased activity of the cerebrum. This is shortly 

 followed by a dazed feeling. There is a violent itching pain in the 

 upper portion of the medulla oblongata, with nervous trembling." 



It causes burning soreness in the eyes and heat in the internal 

 structure. The eyes look wild and staring and there is a constant 

 movement. There is excoriation in the nares posteriores with 

 sneezing and coryza. There is also an aching pain in the temples. 

 It induces labored breathing, and gradually the whole body comes 

 under its influence. There is an intense excitation of the nervous 

 system, causing a hot flush over the entire body, the pulse is 

 increased ten or fifteen pulsations, with pain in the heart and rest- 

 lessness, which, however, is quickly succeeded by obliviousness.* 



"Experiments upon animals have demonstrated the power of 

 this drug in large doses, to produce prompt paralysis of the motor 

 nerves, while it does not affect the great centers of innervation 

 cerebellum and medulla, the great sympathetic nerve or the smooth 

 or non-striated muscular fibre, neither does it affect the seat of intel- 

 ligence, the heart rhythm, the temperature, or the peristaltic 

 action, "f 



Properties and Uses. Dr. William Hamilton, of England, 

 speaks of this plant as a powerful narcotic, capable of producing 

 sleep and relieving pain in an extraordinary manner. 



*George William Wiaterburn, M. D. 



tProf. Fernando Altamarano, M. D., of Mexico. 



