KEPOnT OF THE MICROSCOPIST. 147 



Fig. 7. Armour's oleomargarine boiled and cooled, x 140. 



JJ'iG. 10. A specimen of oleomargarine composed mostly of stearin and cotton-seed 



oil. X 110. 

 Fig. 8. Boiled butterine (Armour's make), sho-wing the oleo crystals, x 110. 



The above crystals were all photographed by polarized light, except in the case of 

 Fig. 1, wliich was jjliotographed by plain light. 



PLATE VI. 



CRYSTALLINE FORMATIONS OF VARIOUS FATS. 



Figs. 1 and 3. Respectively, primary and secondary crystals of loon fat. x 110. 

 Figs. 2 and 8. Primary and secondary crystals of musk-rat fat. The primary (No. 



2) are always very small, measuring about three one-thousandths of an inch 



in diameter. 

 FiQ. 4. Crystals of oleo. x 140 diameters. (Extract of beef fat.) 

 Fig. 5. Crystals of common lard by plain light, x 400. 

 Fig. 6. Secondary crystals of butter, x 110. 

 Fig. 7. Crystals of beef fat. x 140. 

 Fig. 9. Crystals of deer fat. x 140. 

 Fig. 10. Lard by plain light, x 140. 



Fig. 11. Crystals of the solid fat of cotton-seed oil. x 110. 

 Fig. 12. Neutral lard crystals, immatiire. x 140. 



