— ii7 — 



Prof. Robert reserves further investigations (especially as regards 

 the question to what extent the action of umbellulone in cases of 

 acute poisoning may resemble that of pulegone in causing pronounced 

 organic changes, akin to those caused by phosphorus poisoning) and 

 also comparative tests in respect of its antiseptic properties. 



For notes on the pharmaco-physiological behaviour of p-, m-, and 

 o-thymol, see p. 136. 



Phyto* physiological Notes. 



Reference may here be made to a lengthy treatise by O. Tun ma nn 1 ) 

 entitled "Contribution to the knowledge of the cuticular glands", 

 because some volatile oils owe their existence to these glands. The 

 author discusses in the first place the essays dealing with the forming 

 of secretions, and concludes that there is a correspondence between 

 the formation of secretions in the vegetable Kingdom and the same 

 process in the glandular tissues of the human skin, that is to say, the 

 sebaceous glands and gland-surfaces. The secretive matter is only 

 found outside the glandular cells, as it is divided from the plasma of 

 the secernating cells by a wall of cellulose which is always visible. 

 As it has been proved that the secretion occurs only in the sub- 

 cutaceous gland -sacs, it must have originated there, and must have 

 been produced by a resin-secreting membrane. The first investigator 

 who discovered the resin -secreting layer was Tschirch, who gave 

 to this part of the membrane the name of " resinogenous layer" 

 (resinogene Schicht). The determination of this layer in the glands 

 of the skin is easier when the material worked upon has been soaked 

 for one or two months in concentrated aqueous solution of acetate of 

 copper, which hardens it. If fresh material is employed, the modus 

 operandi, according to Tunmann, should be as follows: Delicate 

 horizontal cuts should be made, so that the glands may be inspected 

 from above, or in diagonal section. Next add an aqueous solution 

 of chloral hydrate (10, 20, 30 or 4O°/ ). If the layer should not 

 yet be visible the strength of the solution should be increased by 

 degrees until the major part of the resin has been dissolved. Now 

 exert with the finger a gentle pressure upon the side of the covering- 

 glass. This will burst the cuticle and push it aside, while the resin- 

 ogenous layer will be placed either upon the top of the secernating 

 cells, or, separated from the latter, at the side of the gland-head. It 

 is not necessary that all the resin should be dissolved. Staining with 

 diluted tincture of alkanet will show the residual resin, leaving the 

 resinogenous layer uncoloured. 



*) Berichte d. deutsch. pharm. Ges. 18 (1908), 491 to 540. 



