DISEASES OF PERIOD OF GROWTH. 1027 



by the coalescence of the ossific centres of the head arid two tuberosities, 

 unites with the shaft at about the twentieth year ; whilst its lower extremity 

 is completed by the junction of the external coudyle and of the two parts of 

 the articulating surface (previously united with each other), at about the 

 seventeenth year, and by that of the internal coudyle in the year following. 

 The superior epiphyses of the Radius and Ulna unite with their respective 

 shafts at about the age of puberty ; the inferior, which are of larger size, at 

 about the twentieth year. The epiphyses of the Metacarpal and Phalangeal 

 bones are united to their principals at about the twentieth year. In the 

 Lower extremities the process of ossification is completed at nearly the same 

 periods as that of the corresponding parts of the upper. The consolidation 

 of the Ilium, Ischium, and Pubis, to form the Os Innominatura, by the 

 ossification of the triradiate cartilage that intervenes between them in the 

 acetabulum, does not take place until after the period of puberty ; and at 

 this time additional epiphyses begin to make their appearance on the crest 

 of the ilium, on its anterior inferior spine, on the tuberosity of the ischium, 

 and on the inner margin of the pubes, which are not finally joined to the 

 bone until about the twenty-fifth year. 



874. The rapid increase in Viability which shows itself in both sexes up 

 to the age of puberty, its rapid decline from that point, and its subsequent 

 increase in the male up to the age of thirty, have been already pointed out 

 ( 784). The disorders to which the organism is most subject during the 

 several periods which have now been considered, are by no means the same 

 for each. In early Childhood, when there is a great demand for the activity 

 of the Digestive and Assimilative functions, and these have to be exercised 

 upon nutriment to which their organs are not yet accustomed, we find de- 

 rangements of those organs to be among the most common of all maladies ; 

 these may be serious enough in themselves to constitute dangerous and even 

 rapidly fatal diseases ; but even when they do not take these acute forms, a 

 foundation is often laid, in habits of perverted Nutrition thence arising, for 

 disorders of a more chronic nature (especially those depending on the Tu- 

 bercular diathesis, 378), which may not manifest themselves for many years 

 afterwards. The peculiar activity of the nervous centres, which is prolonged 

 from Infancy into early Childhood, involves a continued liability to derange- 

 ments of their nutrition or of their functions ; and thus it happens that in 

 young children of scrofulous temperament, it is either in the mesenteric glands, 

 or in the brain or its membranes, that tubercular deposit first takes place. 

 The second Dentition, like the first, is often accompanied with a great deal 

 of constitutional disturbance ; especially in such individuals as are suffering 

 from defective Nutrition, or from an irritable state of the Nervous System. 

 In the former case there is a special proneness to Tubercular disease; 1 in the 

 latter, to Epilepsy, Chorea, or some other form of disorder of the nervous 

 centres, the connection of which with Dentition is shown by its abatement 

 when that epoch has passed. A large part of the sickness and mortality, 

 however, which presents so high a rate during the whole period of Childhood, 

 is due to various forms of Zymotic disease, especially the Exanthemata and 

 Infantile Remittent Fever, and to their sequelce. 2 The attainment of Puberty 



1 It is a very significant circumstance, that of the many specimens of the Anthro- 

 poid Apes which have been brought alive into this country, not one has survived its 

 second dentition ; and that, in almost every case, it has been by tubercular disease 

 that their lives have been thus prematurely cut off. 



2 The effects of affluence and poverty on the duration of life at this period are 

 remarkably shown by the deductions of Caspar of Berlin, who states as the result of 

 his inquiries that of 1000 children born in the families of affluent persons, 911 at- 

 tained the age. of 15 years; whilst of 1000 paupers, only 584 survived to that age. 

 (Beclard, Physiologic, 1862, p. 594.) 



