and notes of habits and peculiarities. The sex, and color of the 

 iris may likewise be indicated, and if not too much trouble, the 

 following measurements in the case of skins of mammals : 1st, 

 Length of head to the occiput ; 2d, Length of head and body to 

 the root of the tail ; 3d, Length of tail from root to end of ver'te- 

 briB, and 4th, Length of tail from root to the end of the hairs. 



In many cases it is very difficult to preserve skins of the larger 

 mammals, owing to the amount of arsenic required, the length of 

 time needed for drying the specimens, or the inconveniently large 

 bulk they occupy. All these objections may be readily obviated 

 by the use of a fine powder composed of two parts of alum and one 

 of saltpetre, intimately mixed.* Every portion of the fresh skin 

 should be well covered with this mixture, to which some arsenic 

 may be added, the powder being forced into every corner. It may 

 be most readily applied by means of a tin dredging box and after- 

 wards rubbed in. If the skin be perfectly fresh, it may be folded 

 up, without any stuffing, shortly after application of the powder, 

 and packed away; it will be better, however, to allow it to dry 

 partially, although it should be folded up before losing its flexi- 

 bility. The skin should always be taken, when possible, from a 

 recently killed animal, and the preservative applied at once. Skins 

 prepared in this way will relax sufficiently for mounting by soaking 

 a few hours in cold water. 



Any fat, blood or muscle, which may be attached to the skin, 

 should be carefully removed before the preservative is applied, the 

 surface being kept at the same time moist and fresh, in order that 

 the powder may more readily adhere. ' The first coat may be ap- 

 plied when the skin is inverted, and the hair inside ; it should, 

 after a little while, be returned to its natural condition, and a 

 second quantity of the powder added. 



The skin should be folded up something like a coat, the hair 

 side outward; the head, feet and tail, properly adjusted. In small 

 specimens, the folding may be omitted, and the skin kept in a flat- 

 tened state. In animals less than a fox, a little stuffing may be 

 used to fill out the head, and a small portion placed in the skin and 

 legs. As little, however, should be used as possible, as it is an 

 important object to diminish in every way the bulk of the prepara- 



* The use of this mixture was first suggested to the Smithsonian In- 

 stitution by Mr. John G. Bell, of New York. 



