372 



IXCKEASE IN SIZE AND WEIGHT. 



Reverdin cut a piece of skin into pieces about the size of a pea and fixed them on an ulcerated 

 surface, where they, as it were, took root, grew, and sent off from their margins epithelial out- 

 growths, so that ultimately the whole surface was covered with epithelium. [White skin 

 transplanted to a negro ultimately becomes pigmented, and black skin transplanted to a white 

 person becomes white.] The excised 'spur of a cock was transplanted and fixed in the comb of 

 the*8ame animal, where it grew {John Hunter). P. Bert cut off the tail and legs of rats and 

 transplanted them under the skin of the back of other rats, where they united with the adjoin- 

 ing parts. Oilier found that, when periosteum was transplanted, it grew and reproduced bone 

 in its new situation. Even blood and lymph may be transfused (Transfusion, 102). [Small 

 portions (1 "5 nun.) of epiphyses, costal cartilage, of a rabbit or kitten, when transplanted quite 

 fresh into the anterior chamber of the eye, testis, submaxillary gland, kidney, and under the 

 skin of a rabbit, attach themselves and grow, and the growth is more rapid the more vascular 

 the site on which the tissue is transplanted. The cartilage is not essentially different from 

 hyaline cartilage, but the cells are fewer in the centre, while the matrix tends to become fibrous. 

 Small pieces of epiphysial cartilage introduced into the jugular vein were found as cartilaginous 

 foci in the lungs. Tissues transplanted from embryonic structures grow far better than adult 

 tissues. If a portion of the cornea of a rabbit be transplanted to a human eye, provided 

 Deseeinet's membrane be clear, it will grow and remain clear (v. Hippell). A rabbit's nerve 

 has been transplanted to the human subject, but without success.] 



Many of these results seem only to be possible between individuals of the same species, 

 although Helferich has recently found that a piece of a dog's muscle, when substituted for 

 human muscle, united to the adjoining muscle, and became functionally active. [J. R. Wolfe 

 has transplanted the conjunctiva of the rabbit to the human eye.] Most tissues, however, do 

 not admit of transplantation, e.g., glands and the sense-organs. They may be removed to 

 other parts of the body, or into the peritoneal cavity, without exciting any inflammatory re- 

 action ; they, in fact, behave like inert foreign matter. 



246. INCREASE IN SIZE AND WEIGHT. The length of the body, which at birth is usually 

 i\ of the adult body, undergoes the greatest elongation at an early period : in the first year, 

 20 ; in the second, 10 ; in the third, about 7 centimetres ; whilst from % five to sixteen years the 

 annual increase is about 5 centimetres. In the twentieth year the increase is very slight. 

 From fifty onwards the size of the body diminishes, owing to the intervertebral discs becoming 

 thinner, and the loss may be 6 to 7 centimetres about the eightieth year. The weight of the 

 body (is of an adult) sinks during the first five to seven days, owing to the evacuation of the 

 meconium and the small amount of food which is taken at first. Only on the tenth day is the 

 weight the same as at birth. 



The increase of weight is greater in the same time than the increase in length. Within the 

 first year a child trebles its weight. The greatest weight is usually reached about forty, while 

 towards sixty a decrease begins, which at eighty may amount even to 6 kilos. The results of 

 measurements, chiefly by Qnetelet, are given in the following table : 



Between the twelfth and fifteenth years the weight and size of the girl are greater than of the 

 boy. Growth is most active in the last months of fcetal life, and afterwards from the sixth to the 

 ninth year until the thirteenth to the sixteenth. The full stature is reached about thirty, but 

 not the greatest weight. 



