312 N. E. BROWiV, SOME NOTES OX SEEDS AS MICROSCOPIC OBJECTS 



Finally, the familiar Brazil Nut is a seed of some interest to 

 microscopists, although I have not met with more than two of 

 three who have considered it worthy of their attention. A thin 

 section of the edible part, nicely stained, will exhibit aleurone 

 grains to perfection, whilst a section of the shell makes quite an 

 interesting object, especially if taken near one end of the nut, 

 where, upon breaking the shell, an inner pale-coloured layer is 

 sometimes seen. A section at this point shows an outer layer of 

 transverse elongated cells, with their longer axis perpendicular to 

 the surface ; next a middle layer of very irregularly formed cells 

 with thick red-brown walls ; and an inner layer of transparent 

 cells with very thick walls and of a very remarkable compound 

 structure, as if with four or five centres. Also the Brazil 

 nut sometimes, although rarely, undergoes a chemical change, 

 possibly dae to some disease, whereby white crystals are formed 

 within it. If these crystals are melted and mounted they form 

 an extremely beautiful polariscope object, one that can scarcely 

 be surpassed. Another feature of interest, but in no way con- 

 nected with microscopy, is the manner in which the germination 

 of the Brazil nut aptly illustrates the doctrine of the " survival 

 of the strongest.''^ When ripe, the nuts are enclosed in a sub- 

 globose seed-vessel, 5-6 in. in diameter, with a wall about half 

 an inch thick and very hard, closed by a small lid at the apex, 

 which adheres so tightl}^ that upon the fall of the fruit, perhaps 

 from a height of 100 ft., it does not become detached, nor does 

 the fruit break open, and water cannot penetrate it. After 

 about eighteen months the seeds germinate inside the fruit, the 

 voung stems make their way to the lid, and after a while it either 

 becomes detached or is forced off, leaving a small hole through 

 which the young seedlings find their way. As it takes four to 

 six years for the hard case of the fruit to decay, each seedling 

 strives for the mastery and the weaker become strangled in the 

 hole in succession by the stronger, until only one, the victor, is 

 left. Originally the fruit contains from fourteen to twenty-one 

 nuts. 



Journ. Qi'.ekett Microscopical Club, Scr. 2, fol. XI No. t>0, Nocemher 1911. 



