248 PROCEEDINGS OF THE NATIONAL MUSEUM. 



well as after the first month, with always the same method of drainage, 

 but without a change of solution. 



The method of draining steadily adhered to and applicable to speci 

 mens of all sizes, is to take the brain carefully into one or both hands, 

 and then swing the arms with a somewhat rapid motion from fore 

 backward, by which most of the liquid attached to the brain is thrown 

 oti'; this takes only a brief time, after which the brain is placed for 

 five minutes upon a dry cotton towel. This procedure gives a good 

 and fairly uniform drainage, and is preferable to the use of funnels. 



In the second category of cases one of several additional procedures 

 introduced was proportioning the quuntit}' of the preservative, in 

 cubic centimeters, to the weight of brains, in grams. 



The solutions chosen for the specimens here dealt with were 3 per 

 cent, 5 per cent, 10 per cent, and 15 per cent formalin (commercial 

 solution of formaldehyde) in distilled water; two solutions of for- 

 malin, 5 per cent, to which was added salt, in one case enough to raise 

 the specific gravity to 1,035," and in the other to 1,030; and in addi- 

 tion the writei' used several combinations of formalin with solutions of 

 ordinary alum (potassium and aluminium sulphate), which was chosen 

 for its astringent effects on organic tissues. In two series a saturated 

 solution of alum* was mixed with one part of water, and in another 

 with two parts of water. 



•The changes to which most attention was paid, and which probably 

 represent best the physical changes, were, as with Donaldson, and 

 Flatau, those of weight. The general and specific results follow: 



The changes in the weight of brains in all the mixtures showed 

 (1) a characteristic type for every solution, and (2) a noticeable variation 

 for every solution. 



(1) In every solution the first three to five days were with all brains 

 the period of the most rapid changes in weight. In probably all of 

 the solutions here reported upon, and with all brains, there was an 

 initial stage of gain. This reached more or less promptly its maxi- 

 nuun. and was followed by a general, long-continuing loss. A period 

 of stal)ility was established but slowly. So far as the observations 

 went (two years), absolute stability in weight of the specimens was not 

 reached. In every solution the daily changes in the brain weight 

 formed a characteristic curve. This will be better illustrated in 

 Part II. 



In all the simple solutions of formalin in water, up to 15 per cent of 

 the former (the strongest tested), the initial gain was well marked. 

 It was larger with the weakest solution and decreased as the propor- 



" Near the speeilic gravity of the whole brain; after Spitzka. 



f> A saturate.! sohuion of alum Avas prepared l)y placin-r an excess of that salt in a 

 larjre jar of water, stirring' well, allowing the mixture to stand at ordinary tempera- 

 ture for several days, and filtering just before using. 



