PHYSIOLOGICAL CHEMISTRY. 



FIG. 1. 



FIBULA TIED IN A 



by osseous matter, which contains a larger proportion of calcareous 

 salts ; while the anatomical texture of the parts is also changed, giving 

 rise to the characteristic forms of bony tissue. This progressive con- 

 solidation of the skeleton is known as the process of " ossification." 

 In some instances it is defective, owing to partial 

 failure in the powers of assimilation ; and as the 

 rigidity of the skeleton does not increase in propor- 

 tion to the weight of the body and the force of mus- 

 cular action, the bones become gradually bent and 

 deformed, sometimes to an extraordinary degree. This 

 affection has received the name of Rachitis. 



A similar result is produced by a morbid softening 

 of the bones, sometimes occurring in adult life, known 

 as Osteomalakia. In this disease the bony fabric, after 

 its formation, becomes altered in texture and compo- 

 sition, and, the new substance which takes its place 

 being deficient in calcareous matter, there is a pro- 

 gressive yielding and deformity of the skeleton, like 

 that which happens in rachitis. 



In the plasma of the blood the lime phosphate, 

 though insoluble in alkaline watery liquids, is held in 

 solution by union with the albuminous ingredients. 

 It has been shown by Fokker that the earthy phos- 

 phates added to white of ege: unite with the albu- 



KNOT, after macera- L . '-,-,-, 



tion in a dilute acid, minous matter and become soluble in considerable 

 From a specimen pre- proportion. This explains the presence of lime phos- 

 phate in a liquid form in the blood and in the milk, 

 both fluids with an alkaline reaction. In the urine, on the other hand, 

 it is held in solution by the acid sodium biphosphate. Accordingly, 

 when the urine is rendered alkaline by the addition of soda or potassa, 

 the earthy phosphates are precipitated, forming a white turbidity. 



The source of the lime phosphate of the animal solids and fluids is in 

 the food. It exists in nearly every animal and vegetable alimentary 

 matter in common use. It is found not only in muscular flesh, eggs, 

 and milk, and in all the cereal grains, as wheat, rye, oats, barley, maize, 

 and rice, but also in peas and beans, the nutritive tubers and roots, as 

 potatoes, beets, turnips, and carrots, and even in juicy fruits, such as 

 the apple, pear, plum, and cherry. 



After forming for a time a constituent part of the body, the lime 

 phosphate is discharged with the excretions, but slowly and in small 

 amount. According to the observations of Neubauer and Beneke, 

 about 0.4 gramme, on the average, is daily expelled with the urine. 

 A slightly larger quantity is found in the feces, but this may be only 

 a residue from the undigested portion of the food. Only traces of it 

 are to be detected in the perspiration. As so large a quantity of this 

 salt, therefore, is contained in the body, while so little is expelled 

 daily with the excretions, it is evidently one of the more permanent 



