THE HUMAN SPECIES 



the body ; gas is set free, and the blood coagulates in the veins 

 and right side of the heart. 



The acquired hypertrophies and atrophies of certain 

 parts of the body (such as acromegaly and the stunted 

 growth of rickety children) are not the only ones which are 

 included in the domain of comparative pathological anatomy. 

 All congenital anomalies, whether affecting the whole body 

 or only a part, are not less common among animals (at any 

 rate among domestic animals) than among men. 



Giants and Dwarfs. A man 190 centimetres (6 feet 3 

 inches) is abnormally tall ; giants proper are men who reach at 

 least 200 centimetres (6 feet 6 inches), but their maximum 



height cannot be definitely settled. 

 Their bones alone are hypertro- 

 phied without a corresponding in- 

 crease in the size of the muscular, 

 nervous and vascular systems. They 

 are therefore less resistant to exter- 

 nal influences, they are sluggish and 

 have little energy, and are usually 

 incapable of reproduction. This 

 applies less to the shorter, thick-set 

 giants with large trunks and almost 

 normal limbs, and more to the lanky 

 FIG. 191. Giant tadpoles of Rana long-legged ones, the upper part of 



esculenta, J natural size. whose bo(jies js short Those Q f 



the first type are often shown post-mortem to be subjects of 

 acromegaly with tumour of the pituitary body in the brain. 

 Giants seldom live to any great age. 



Giants are less common among animals than dwarfs. 

 Among wild animals giants have been found in all classes and 

 orders (for example, among stags, elks, turtles, salamanders, 

 sharks) ; these forms, however, which have become fixed species 

 are of less interest than those which under peculiar circumstances 

 have exceeded the normal size, as, for instance, the enormous 

 pike and carp of certain lakes, and the tadpoles which were found 

 in a wet secluded grave at Frankfort-on-the-Main by Brugsch. 1 



1 Brugsch, C., "Ueber Riesen- und Zwergformen bei den Betrachiern," 

 Zoolog. Garten, 1864, p. 349. 



