THE TEXTILE PLANTS OF THE WORLD. 831 



erally, then, that the intelligence of an animal depends principally upon 

 the size of the brain in proportion to the size of its body, the size of 

 the cerebrum, and also upon the number of convolutions and the com- 

 plexity of its structure, although there are many exceptions to this rule 

 which we are still unable to account for. 



Another interesting point in connection with this subject is the 

 great increase in the size of the brain that has taken place within the 

 last few hundreds of years, without a corresponding increase in the 

 size of the body in all animals. This very interesting fact we learn 

 from fossil zoology. The brain of animals at the present day is much 

 more developed than it was in former times. This may be owing to 

 the struggle for existence which there is, the animals which are weaker 

 in body and intellect gradually being extinguished by the stronger, so 

 that only the latter remain and are allowed to propagate the species. 

 We know that exercise and training strengthen the brain and increase 

 its weight in man, so the probability is the same thing takes place 

 among the lower animals. There is every likelihood, therefore, that 

 the brain will siill go on developing as time advances. — Land and 

 Water. 



THE TEXTILE PLANTS OF THE WOELD. 



DR. HERMANN GROTHE, of Berlin, has published a work on 

 the textile fibers fiirnished by the world of plants, embodying 

 the fruits of studies pursued among the yarn and clotk materials of all 

 nations at the great Industrial Exhibitions that have been held at the 

 European capitals and in Philadelphia. The subject is one of much 

 interest, in an economical sense, and in the relation it bears to the de- 

 velopment of early civilization. Men's first steps in civilization may 

 be traced almost directly in their efforts to clothe themselves ; and 

 their first essays in skilled labor are made in the adaptation of the ma- 

 terials which nature has furnished them to use for dress. On the banks 

 of the White Nile are tribes who content themselves with simple 

 aprons of leaves, or less ; and Sir Samuel Baker noticed that a great 

 advance in general civilization had taken place when, after having 

 spent several months among peoples of that grade, he came into Unyoro, 

 where the people wore garments fashioned out of the bark of a fig- 

 tree, which they had to prepare by soaking and beating w<th a mallet. 

 Thrift seemed to follow naturally upon the acquisition of the taste for 

 clothing, for the fig-trees have to be cultivated to secure a sufiicient 

 supply. Accordingly we are told, when a man takes a wife, he plants a 

 certain number of the trees in his garden, as a provision for the wants 

 of the family he has in prospect. A grade above the naked races are 

 the Papuans of New Guinea, with their loin-girdles of grass or palm- 



