CHAP. VII.] THE CONNECTIVE TISSUES. '277 



elusions. This matter will be referred to again (p. 282) in considering 

 the etiology of Rickets. 



It was asserted by Papillon 1 that when animals are supplied with 

 food specially rich in magnesium, aluminium, and strontium salts, 

 these elements enter into the composition of the mineral matter of 

 the bones. J. Konig 2 contradicts the researches of Papillon in so far 

 as compounds of magnesium and aluminium are concerned, but 

 confirms them in respect to strontium. In the bones of rabbits 

 fed with strontium phosphate, he found as much as 5 '37 p. c. of 

 strontium. According to Weiske 3 both Papillon and Konig have 

 fallen into error. In the bones of rabbits fed with strontium phos- 

 phate, Weiske found only minute traces of strontium. 



The Composition of the Marrow of Bone. 



As has been already said, it is customary to distinguish between 

 the yellow marrow, which is contained in the medullary cavity of the 

 long bones, and the red marrow which is lodged in the cancellated 

 tissue of spongy bone. 



The former on microscopical examination has all the characters of 

 adipose tissue, being composed of fat cells supported by connective 

 tissue fibres and blood-vessels ; the latter contains cells which resem- 

 ble the white cells of the blood, and certain cells which resemble the 

 nucleated coloured corpuscles of the blood of the embryo. 



The dried yellow marrow consists chiefly of fat which appears 

 to have the normal composition of the fatty matter of adipose 

 tissue. The red marrow is said to contain albumin and a free 

 organic acid, supposed by Berzelius 4 to be lactic acid. 



Heymann 5 has detected hypoxanthin in marrow of healthy bones, 

 and Nasse 6 has found in the red marrow of the ribs of old horses, 

 microscopic agglomerations of granules, having a diameter of from 

 O'OOT 015 mm., which contain oxide of iron (probably also ferric 

 phosphate) and organic matters and are coloured intensely blue by 

 ferrocyanide of potassium ; these are identical with similar bodies 

 found in the spleen of man and the horse. 



These chemical facts, taken in connection with the observations 

 of cases of myelogenic leukaemia, give great countenance to the view 



1 Papillon, " Recherches experimentales sur les modifications de la composition 

 immediate des os." Comptes Rendus, Vol. LXXVI. (Ib73) p. 352. 



2 Konig, " Substitution des Kalkes in den Knochen und Einfluss kalkarmer Nahrung 

 auf die Zusammensetzung der Knochen." Ijeitschrift f. Biolog., Vol. x. p. 69. 



Weiske, Zeitschr. f. Biol, Vol. x. p, 410. 



4 Berzelius, quoted by Gorup-Besanez, Phys. Chem., p. 631. 



5 Heymann, " Ueber das Vorkommen von Hypoxanthin im normalen Knochen- 

 marke." Pfliiger's Archiv, Vol. vi. p. 184. 



B Nasse, "Ueber das Vorkommen eisenhaltiger Korner im Knochenmarke." Ab- 

 stracted in Maly's JahresbericM, Vol. vn. (1878) p. 300. "Ueber den Eisengehalt der 

 Milz." Maly's Jahresbcricht, Vol. iv. (1874) p. 91. 



