EFFECTS OF FORMALDEHYDE ON BRAIN OF RAT 313 



9. A 4 per cent solution of formaldehyde extracts solids from 

 the brains of rats of all ages. This is shown by the fact that 

 the percentage of solids in brains that have been subjected to 

 the action of such a solution is always less than that found in 

 the fresh brains of animals of the same age. Brains of very 

 young rats lose much more of their solids than do brains of older 

 animals. 



10. Brains of animals infected with pneumonia show a slightly 

 greater percentage weight increase when treated with a 4 per 

 cent solution of fomialdehyde than do the brains of healthy 

 animals. 



11. Even under the most favorable conditions an aqueous 

 solution of formaldehyde is not a satisfactory fixative for the 

 cell structures in brain tissues, as it causes a pronounced disten- 

 tion of the nuclei and gives a poor preservation of the nuclear 

 contents. 



LITERATURE CITED 



Baton, P. G. 1905 Die histologischen Untersuchungs-Methoden des Nerven 

 systems. Wiirzbiirg. 



Blum, F. 1893 Der Formaldehyd als Hartungsmittel. Zeitschr. wiss. Mikr., 

 Bd. 10. 



BoDECKER, C. F. 1906 Zur doppelten Einbettung in Celloidin und Paraffin. 

 Zeitschr. wiss. Mikr., Bd. 25. 



BouiN, P. 1897 Ph6nomenes cytologique anormaux dans I'histogendse et I'atro- 

 phie experimentale du tube seminfere. Arch. Anat. mikr., T. 1. 



Donaldson, H. H. 1894 Preliminary observations on some changes caused in 

 the nervous tissues by reagents commonly employed to harden them. 

 Jour. Morph., vol. 9. 



1908 A comparison of the albino rat with man in respect to the growth 

 of the brain and of the spinal cord. Jour. Comp. Neur., vol. 18. 



1909 On the relation of the body length to the body weight and to 

 the weight of the brain and of the spinal cord in the albino rat. Jour. 

 Comp. Neur., vol. 19. 



1910 On the percentage of water in the brain and in the spinal cord 

 of the albino rat. Jour. Comp. Neur., vol. 20. 



Fi-H, P. A. 1895 The use of formalin in neurology. Proc. Amer. Micr. Soc, 

 '^ vol. 17. 



