246 PROCEEDINdS OF THE NATIONAL MUSEUM. 



Effoj-ts have been made to correct the faults of formalin b}- the 

 addition of other substances to its solutions, or l)y following- these, 

 after the desired hardening of the brain had been eti'ected, with other 

 preservatives. Tt has been combined with or followed by various pro- 

 portions of alcohol (Parker & Floyd, Marie, Gerota, etc.), potassium 

 bichromate, or Miiller's fluid (Diedrichs, G. Retzius), glycerin (Lan- 

 zillotti-Buonsanti, Chencinski), sodium acetate with sodium chloride 

 and alcohol (Stroud, Wilder), sodium chloride and zinc chloride (Fisk), 

 sodium chloride alone (Spitzka). and bichloride of mercury." All of 

 these combinations have been reported upon favorably. The eti'ects 

 of several formalin solutions have been observed * with some detail, 

 but of no single solution do we possess exact and sufficiently detailed 

 data as to its action on the ])rain, especially' physically, and its action 

 on the brains of persons of different ages, or on those of diflerent 

 animals, or rinall}' on those collected under widelv different conditions 

 of the organ, or of temperature. Yet it is important to be acquainted 

 with such facts. It is desirable to know which really is the best solu- 

 tion or combination for at least most of the specimens, so that such a 

 preparation alone may be used. Such knowledge would tend to bring- 

 about not only a much-desired unit}^ of procedure, but also a general 

 undci-standing, at any stage, of the state of our material, so far as 

 formalin preservation is concerned. The use of a single solution with 

 well-known effects would regulate our records and methods, and allow 

 of a degree of accuracy in weight determinations and measurements 

 not now possible. 



With these facts in mind, and remembering the excellent work l)v 

 Donaldson in 1894 on the physical changes in the brain produced by 

 various preservatives in use before the introduction of formalin, the 

 writer, in establishing a brain collection in the Department of Anthro- 

 pology of the United States National Museum, has endeavored to make 

 a series of tests with several solutions, the main component of which 

 was Merck's formalin. 



The material accruing to the ])rain collection of the Museum is 

 hetei-ogeneous, ranging from man's braius'' to those of the lowest 

 manunals,'' and from aged individuals to embr3"os, hence it was par- 

 ticularly suitable for experiments. Besides this it is alwaj^s possible 



« Still other {-orapositionH were employed for the purposesi of histology and pathol- 

 ogy — see Huiiimary in TellyeHnitzki. Special methods, also, having no bearing on 

 the theme of this paper, were devised for the j)reservation of the natural color of 

 vaiioiis organs. 



^ See Dexler, p. 382, after Flataii; records of the weight of the brain in 1 per cent, 

 5 per cent, and 10 per cent formalin solutions in 1, 3, 30, 1)0, 150, and 450 days. 



•■Of these, unfortunately, not a sufficient number were received in good condition 

 during the progress of the experiments. 



''The term "mammal" is used, for want of a better term, throughout this i)ai)er 

 as a designation f(jr other mammals than man. 



