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HELEN DEAN KING 



Age of rat. 

 New bom: 



200 days. 



Pfircentage weight increase. 



Time in days. 



Chart 9 Showing the weight changes in brains of rats of various ages, each 

 remaining for four weeks in 40 cc. of a neutralized solution of 4 per cent formal- 

 dehyde kept at a temperature of 8 to 11°C. 



Chart 10 Showing the final percentage weight increase in two series of rats 

 brains kept at different temperatures during the four weeks they remained in a 

 neutralized solution of 4 per cent formaldehyde. A, solutions kept at a tem- 

 perature of 36°C. ; B, solutions kept at a temperature of 8 to 11 °C. 



