INFLAMMATION. 399 



new formation of fibrous connective tissue, resulting in thinning 

 of the bone. In other places the exuberant growth of medullary 

 tissue causes a broadening of the diameter of the bone, with a 

 scanty trabecular new formation of bone-tissue. Both the medul- 

 lary and the newly formed connective tissue are supplied with a 

 considerably larger amount of blood-vessels than is seen in the 

 normal condition. 



The pathological condition is that of a plastic inflammation, in 

 accordance with the views expressed by Virchow, and there is good 

 reason to consider the process of rachitis as an inflammation. 



By feeding pups and kittens with lactic acid, rickets was 

 induced, exhibiting in the osseous system features identical to 

 those observed in rachitic children. 



Osteomalacia. This rare form of disease, which is always 

 accompanied by intense pains, usually attacks the vertebral col- 

 umn and the pelvic bones, though there are cases on record in 

 which the whole skeleton was rendered as pliable as wax. 



Under the microscope we see a decalcification of fully formed 

 bone-structure, usually of the compact portions, advancing in a 

 way similar to the inflammatory process. The bone-tissue is 

 transformed into medullary tissue, which in some places is distin- 

 guished by a large quantity of blood-vessels. My researches 

 enable me to state that the ultimate productions from medullary 

 tissue are of two kinds : either colloid globules or simply fibrous 

 connective tissue. 



In a femur of a woman who, during pregnancy, was attacked 

 with osteomalacia, and died of the disease, the compact portion 

 of the bone was reduced to the thinness of a pasteboard, and 

 was very pliable. The central marrow space was filled with a 

 smeary, grayish yellow mass, which, under the microscope, proved 

 to be colloid viz. : consisted of globular or irregularly shaped 

 corpuscles of a luster similar to fat, but not yielding to the 

 re-agents which dissolve fat. They resisted even the action of 

 strong alkalies and acids which destroyed the bone-tissue proper,, 

 and assumed a dark purplish violet color upon being stained with 

 chloride of gold. (Fat is unaffected by chloride of gold.) Within 

 the globules radiating bodies were often seen, somewhat similar 

 to the needle-shaped crystals of the so-called margaric acid. 

 Between the globules scanty fibrous connective tissue with a few 

 blood-vessels was noticeable. 



The origin of the colloid corpuscles could be traced in the thin 

 compact shell of the femur, in which the lamellae were much . 



