26 PROCEEDINGS OF THE ACADEMY OF [1884. 



not been careful enough to remove every particle of water, I 

 always take the precaution of changing the absolute alcohol once 

 or twice, especially in moist climates. 



After all the water has been withdrawn by the absolute alcohol, 

 by remaining in it for three daj's to a week, the object is placed 

 in turpentine, the best that can be procured. In this it is allowed 

 to remain until it becomes thoroughly saturated — with large 

 objects it is best to change the turpentine once. Two or three 

 days are required for this stage. When saturated the object is 

 quite stiff, and when the process is successful little or no contrac- 

 tion has taken place. The object is then placed in the air and 

 protected carefully from the dust, and the turpentine allowed to 

 evajjorate. The object then soon presents a very beautiful 

 appearance ; it becomes white, resembling the whitest kid. It is 

 light, stiff and, on account of the resin it contains, is perfectly 

 insect-proof. 



In annelides the iridescence is perfectly kept ; hair and feathers 

 retain their original colors. 



If hollow organs, as the stomach, bladders, lungs, etc, are to 

 be prepared, they may be blown up after they have been a short 

 time in the turpentine ; by so doing much space, and consequently 

 much alcohol, are saved. 



This is the practical part of the method, and I may add in a 

 few words the whole principle. The object is to earefull}'^ and 

 slowly harden the tissue and to remove every particle of luater, 

 the place of which is taken by the resin. 



If the process be hurried contractions are apt to occur, and 

 consequently bad-looking specimens result. 



The advantages of this method are great. We have a perfectly 

 dry object, with the perfect form kept ; it is far preferable to 

 handle than alcoholic dissections or preparations. It will last 

 indefinitely and is insect-proof. 



Prof, Semper keeps his preparations in glass boxes which are 

 perfectly dust-proof, and by this both sides of the preparation 

 can be distinctly seen. 



An addition to this process was discovered by Prof, Semper 

 about two years ago, which I do not think has yet been published. 

 It is to place the prepared object in a solution of glycerine and 

 sugar. In some objects this brings back almost entirely the 

 original color of the animal ; one disadvantage of this is, however, 



