The Preservation of Material. 195 



3f the fluidy and the height of the pressure column. Not less than 

 L500 cc. should be allowed for each specimen. 



The apparatus needed for embalming includes a reservoir for the 

 3uid, provided with an exit pipe to which a rubber tube may be at- 

 tached; about 6 feet of rubber tubing to connect with the operating 

 table; several three-way pieces to divide the stream in case several 

 specimens are to be handled at the same time; selected rubber tubing 

 }f the size indicated below to attach the cannulae; clamps for the 

 tubing; and, finally, glass or metal cannulae for insertion into the femoral 

 irtery. 



Glass cannulae suitable for the purpose are readily made by heating 

 Drdinary glass tubing over the Bunsen flame and drawing it out to the 

 iesired thinness. The tubing used for the purpose should be of about 

 3 mm. outside diameter. The cannula when completed should be about 

 7 cm. long; and its narrow end should have a uniform diameter of 

 L.5-2 mm. for about 2 cm. at the tip. The tip should be touched lightly 

 n the flame in order to round the margin by fusion, otherwise it might 

 lamage the wall of the vessel. 



The rubber tubing used to connect the cannula with the main tube 

 should be of the best quality of soft rubber, and should have an inside 

 liameter of 4mm., i.e., of proper size to slip on and off the cannula easily, 

 jut yet to retain its hold on the latter under moderate pressure. 



The reservoir for holding the embalming fluid may be an aspirator or 

 rrigator bottle, an enamel fountain, percolator or ordinary funnel. It 

 nay have a capacity of one or two quarts. The capacity, however, is 

 mmaterial, so long as the operator keeps the fluid replaced. The 

 eservoir is suspended in such a way that it may be moved up and down 

 vithin a distance of four feet above the top of the operating table. 



At the time of beginning the embalming process the operator should 

 lave before him the reservoir, suspended at a height of about three 

 eet, and a column of fluid, free from air : bubbles or foreign material to 

 he tip of the cannula. This condition must be maintained throughout 

 he operation. If at any time the pressure falls in the apparatus 

 ufficiently to admit air, or allow coagulated blood to run back through 

 he cannula, there is almost certain to be trouble, not only with the 

 pecimen under treatment, but also others which come after. The 

 olumn of fluid is held back until the proper time by a clamp placed on 

 he rubber tubing. 



The animal is killed by administering ether or illuminating gas. It 

 3 placed on its back on the table, with the head away from the operator, 

 "he skin is first divided by a small incision on the inner side of the right 

 high.* By inserting the fingers well down into the incision, the skin 

 aay be torn backward and toward the ventral middle line, and at the 

 ame time the superficial epigastric vessels will be carried with the 

 ubcutaneous tissue well out of the operator's way. Small portions of 



* The embalming may be done from the common carotid artery of the neck, a 

 essel much larger than the femoral artery and therefore easier of manipulation, 

 his is not recommended , however, because of the damage done to" various, important 

 ;ructures of the cervical region. 



