26 STRUCTURE AND PHYSIOLOGY OF SEED PLANTS 



amount of liquid as was used at first. Let the liquid stand in a 

 saucer or evaporating dish in a good draft till it has lost the 

 odor of the ether or benzine. Weigh the remaining oil and cal- 

 culate what per cent of the ground seed was oil. (Traces will of 

 course still be left in the residue on the filter.) 



Describe the oil which you have obtained. Of what use would 

 it have been to the plant ? 



EXPERIMENT IX 



Detection of proteids in seeds. Extract the germs from some 

 soaked kernels of corn and bruise them, or soak some wheat-germ 

 meal for a few hours in warm water, or in a stream of water wash 

 the starch out of wheat-flour dough ; reserving the residue for 

 use, place it in a white saucer or porcelain evaporating dish and 

 moisten well and heat with Millon's reagent (Sec. 170) or with 

 nitric acid ; examine after fifteen minutes. Proteids turn yellow 

 when moistened with nitric acid and red with Millon's reagent. 



E.EFEBEKCS. Strasburger-Hillhousc, 6. 



EXPERIMENT X 



What plant foods are found in Brazil nuts ? Crack several Brazil nuts, peel ofi 

 the brown coating from the kernel of each, and then grind the kernels to a 

 pulp in a mortar. Shake up this pulp with ether, pour upon a filter paper, and 

 wash with ether until the washings when evaporated are nearly free from 

 oil. The funnel containing the filter should be kept covered as much as 

 possible until the washing is finished. Evaporate the filtrate to procure the 

 oil. Dry the powder which remains on the filter and keep it in a wide-mouthed 

 bottle. Test some of it for starch and for proteids. Does it appear that a 

 seed needs to contain both starch and oil, or may one replace the other ? 



15. Microscopical study of reserve oil in a seed. Cut moderately thin 

 sections of an oily seed, e.g. peanut (not roasted). Mount in water and 

 examine with m.p. Note the cellular structure of the seed and the minute 

 oil globules within the cells. Try to estimate the number in a cell. Mount 

 another section in an alcoholic solution of alkannin or of the soluble portion 

 of alkanet root (Sec. 170). After a few minutes examine the section and note 



