MICROSCOPIC INVESTIGATION. 85 



an alkalic atmospliere may modify the oxidizing conditions. Place lialf 

 an ounce of turpentine in a quart jar, and put in the jar a test-tube con- 

 taining the sulphide of ammoftiium, which is very volatile, taking care 

 that only the gases of each liquid will come in contact. Suspend in this 

 mixed atmosphere a slip of the starch-paper* and exclude common air. 

 After the lapse of twelve hours it will be found that the test-paper is 

 saturated with the sulphide of ammonium, and no tinge of purple or 

 other indication of free iodine is observed ; in this case the atmosphere 

 is highly alkaline. 



If to an aqueous solution of iodide of potassium and starch a few 

 drops of commercial turpentine be added, by agitation a purple color 

 will appear, first on the top, but ultimately the entire mass will appear 

 beautifully stained. If a portion of the liquid be examined under a 

 suitable power of the microscope, it will be seen that the starch granules 

 have become swollen and are tinged a blue-purple. The granules have 

 an appearance of partially-boiled starch, and remain suspended for a 

 long period in the liquid. Slips of iodized starch-paper prepared with 

 very weak solutions of iodide of potassium, hung in an inclosed atmos- 

 phere of turpentine, take a very slight tinge after a lapse of twelve 

 hours. The same changes are observed when other essential oils are 

 used, but when a saturated solution of the iodide of potassium' and starch 

 are used instead, a very deep color is quickly obtained. Sometimes the 

 color will approach to blackness, but is in reality a deep purple, as seen 

 under the microscope. When the oil of bergamot is used with the weak 

 solutions, a very slight change is effected ; but should a drop of the 

 starch mixture fall into this oil, it will take a very deep stain. Nearly 

 all the essential oils behave in a similar manner under similar conditions. 

 The vapor of benzole, supposed to be chemically pure, does not give any 

 appreciable color to iodized paper ; but when droppings of the starch 

 mixture are immersed in the benzole from ten to twenty hours, they be- 

 come deeply stained brown or purplish. It will be seen that various 

 substances of a very dissimilar character, chemically considered, give 

 acid reaction; and those who favor the ozone theory in eucalyptus, 

 coniferous, and other essential oils, will do well to consider the facts 

 above recited. It is only by a full and faithful consideration of all the 

 facts which relate to the changes and conditions that affect the (ozone) 

 test-paper that a knowledge of its value or worthlessness may be under- 

 stood. 



The fleshy sides of the skins of animals may be preserved from putre- 

 faction by rubbing on them eucalyptus oil. It may also be combined 

 with plaster, and injected into the veins and arteries of animals for the 

 purpose of preservation. 



As a result of actual experiment, I find that beef or any animal mat- 

 ter may be preserved by it. I placed two ounces of solid beef in a glass 

 jar with a few drops of this oil, securing the contents from contact with 

 the atmosphere by means of a glass stopper. At the expiration of three 

 months I examined the beef and found it fresh, and on cutting into it 

 the fresh surfaces appeared of a healthy flesh color. I examined the 

 surface, by removing portions of it and placing them in the usual man- 

 ner under a power of about 350 diameters, but no organic germs of any 

 kind were visible. I next removed the beef from the jar, and exposed 

 it to an atmosphere of about 75° F. Within twenty-four hours after- 

 ward the beef dried up, and became very hard, showing no sign of 

 moldiness or i)utrefaction. In consideration of these facts, I deem it 



* Paper dipped iu a solution of iodide of potassium and starch. 



