114 ANATOMICAL TECHNOLOGY. 



has been used for the prescribed purposes within the specified time. It is necessary to 

 make oath before the proper officer to this effect, giving the marks of the alcohol and the 

 date of the original application. This affidavit is to be transmitted to the Commissioner 

 of Internal Kevenue through the Collector of the district in which the institution is located. 



Since it is noc always easy to ascertain the location of warehouses, it may be proper to 

 mention that alcohol may be obtained promptly under the foregoing conditions from Messrs. 

 Geo. & Thos. Farthing, of Buffalo, in the 30th collection district of the State of New York. 



§ 285. InflammabiUty. — At ordinary temperatures— 15-30' C. — a mixture of alcohol 

 and water containing 30 per cent, or less of absolute alcohol cannot be ignited, and 

 promptly extinguishes a lighted match dipped into it; 35 per cent, ignites with difficulty, 

 and the flame is extinguished by the lightest current of air ; 40 and 45 per cent, ignite 

 more readily, but burn gently and slowly. Even 65 per cent, does not burn fiercely, and 

 the flame is easily extinguished. Specimens saturated with alcohol are more combustible 

 in proportion to the strength of the alcohol. 



Other Inflammable Substances. — Still more volatile and inflammable are the ether, ben- 

 zine and spirits of turpentine which are used in anatomical work. 



§ 266. Precautions against Fire. — Alcohol, benzine, ether, and spirits of turpentine in 

 bulk should be stored in a fire-proof vault, or in some small building apart from valuable 

 collections and apparatus. In the laboratory there should be not more than 20 liters of 95 

 per cent, alcohol, and of the other liquids only enough for current uses. All of them 

 should be kept in glass or copper vessels, well stoppered and at a safe distance from all 

 lights and heating apparatus. They should never be opened within one meter of a light, 

 and if there is a current of air toward the light, the distance should be at least doubled. 



When removed from alcohol for examination or dissection, specimens should be washed 

 off with water, and kept wet with the 15 per cent, glycerin solution, as directed elsewhere. 

 This precaution is the more essential when anatomical work is done by artificial light. 



Cotton and cloths which have been saturated with alcohol or other inflammable liquids 

 should be dried on trays in the sun or wind rather than near a fire. Common cotton 

 should be thrown away after use in alcohol, but absorbent cotton may be saved if thor- 

 oughly dried. 



Safety matches are to be preferred. All matches should be kept in metal or glass 

 boxes. After using, matches should be put into a glass or metal receptacle, and never 

 thrown on the floor. 



Smoking in a laboratory where alcohol is used should be absolutely forbidden. 



§ 267. Determination of the Percentage of Alcohol in an 

 Alcoholic Liquid. — This may be done by means of either a Speci- 

 fic Gravity Hydrometer or an Alcoometer (alcoholometer). For 

 zoological purposes the latter instrument is more convenient and 

 sufficiently exact. 



§ 268. Alcoometer (alcoholometer). — Tliis is a form of hydrome- 

 ter or areometer especially adapted to determining the volume or 

 weight percentage of alcohol in a mixture of alcohol and water. 



It is a gradnated tube, loaded so as to rest vertically in any 

 liquid capable of floating it. The alcoometer of Tralles is com- 

 monly employed in this country ; it indicates the volume per cent. 



In pure water the instrument sinks only to zero, the lower end 



