PART II. 



PHYSICAL CHANGES IN SHEEP BRAINS COLLECTED AND PRE- 

 SERVED UNDER SIMILAR CONDITIONS IN VARIOUS FORMALIN 

 PREPARATIONS. 



The first part of this paper dealt with the effects of formalin pre- 

 servatives on the weight of human, other mammal, and bird brains, 

 adult as well as young, collected under various conditions. The results 

 in any solution, although more or less characteristic for that particu- 

 lar liquid, were by no means uniform. It was found that, in general, 

 the changes in the large brains were less than in the small ones, and 

 those in the adult less than in the young. Some of the differences 

 may eventually be found to be those of species or larger subdivisions 

 of the animal kingdom; but be3^ond all this there was seen a consider- 

 able and unaccountable variation. This element was recognized long 

 before the first experiments were completed. It rendered desirable 

 a separate series of observations on the brains of some fair-sized animal, 

 collected equally fresh, extracted and subsequently treated in the same 

 manner, and kept in proportionately the same quantities of the preserv- 

 ative. Under such conditions the action of the various preservatives 

 should be much clearer and more comparable, and the differences in 

 the changes be reduced to the minimum ; if noticeable disagreements 

 still existed, they would point to differences in the structure of the 

 brains or in their chemical composition. 



It became possible to undertake the series of experiments during 

 the earl}" part of the summer just past. An arrangement was made 

 with one of the city butchers to deliver ever}" morning a small series 

 of heads of sheep killed the night preceding. The brains, with the 

 help of the laboratory aid, Mr. Docekal, were extracted in as short a 

 time as possible and in the same manner (see Part I), then weighed and 

 placed in a proportioned quantity of the preservative. Fifteen series 

 were determined upon and the specimens were secured in a little over 

 two weeks, during quite uniformly warm weather. Every series 

 except two, which were smaller, consisted of eleven brains. Ten of 

 the specimens were placed in a quantity of the preserative amount- 

 ing to 3 c. c, for each gram weight of the specimen, while with one 

 the quantity to the gram was made 6 c. c. Of the brains in 3 c. c. to 

 the gram liquid, one of about average dimension was weighed every 

 day the same hour, while the remaining nine and also the eleventh 

 specimen were weighed at the end of seven and again at the end of 



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