164 



THE ENERGY OF THE LIVING PROTOPLASM. 



specific chemical work, and others again are adapted to functions 

 of propagation, while in the animal kingdom special organs for 

 visible motion and for sensation are developed. The " chemical 

 factories in the service of an organism," the glands, of simple 

 structure in plants, but forming complicated organs in the 

 higher animals, betray again a far-reaching differentiation. 

 They may secrete enzymes, carbohydrates, different acids, fat, 

 or wax. Products secreted by vegetal cells alone are terpenes 

 and resins. 1 Glands secreting poisonous compounds (tox- 

 albumins ; carbylamines (?)) occur in the mouth of snakes, in the 

 skin of the toad, on the feet of scolopendras. Crustaceans and 

 beetles produce chitin, spiders and caterpillars fibroin. Carabidae 

 secrete butyric, bees and ants formic acid. Especial interest is 

 connected with the anal glands of the skunk, <2) musk deer, 

 beaver, and civet. Again, the livers of different animals vary 

 in their actions, as must be inferred from the composition 

 of bile and urine. Dogs can produce ethyl sulphide (Abel) 

 and an oxyquinoline-carboxylic acid (Kretschy), birds ornithinic 

 acid; (3) the bile of geese contains chenotaurocholic, that of 

 swine hyotaurocholic acid. Birds and snakes produce more 

 uric acid than urea, while the reverse is the case in mam- 

 malia. The products of metabolism exhibit, thus, considerable 

 discrepancies. (4) 



This very brief survey may bear sufficient testimony to the 

 variety of the chemical work of organisms, and to the special 

 adaptation of the plasmic energy to the most varied chemical 

 performances. Few authors have thus far tried to propound an 



(1) An elaborate treatise on the resin-producing glands of the conifers was 

 recently published by H. Mayr, formerly professor in the Imperial University of 

 Japan. 



(>) The yellow liquid secreted by the skunk-glands and ejected in self-defence is 

 a primitive and effective weapon, having a most repulsive odour. It contains 16 per 

 cent of sulphur (Sivarts), and is probably a mixture of several mercaptans with one 

 or more nitrogenous compounds. 



(3) This acid, a dibenzoyl-ornithin, is secreted after introduction of benzoic acid; 

 ornithin again is probably a diamido-valerianic acid (Jaffl). 



(4) Also, pathological processes may be caused by administration of certain 

 compounds only in certain animals ; thus phloridzin will produce diabetes in dogs, 

 but not in rabbits or frogs. 



