ZOOLOGY. 381 



of blood-cells, while Kolliker and others maintain that it is a destroyer of 

 them. Dr. Henry Draper states (N. Y. Jour. Med., Sept. 18o8) some mi- 

 croscopic investigations made by him on the blood of frogs taken from the 

 splenic artery and splenic vein, and he found the latter to contain at least 

 double the general average of imperfect cells ; whence he infers that " the 

 spleen must be an organ for the disintegration of blood-cells." 



NEW FACT CONCERNING BLOOD. 



M. Claude Bernard has communicated certain observations to the French 

 Academy of Sciences, tending to show that the custom of applying the de- 

 nomination of red blood to that of the arteries, and of black to that of the 

 viens, is not in accordance with facts. Having had occasion to open the 

 renal veins of various animals, M. Bernard found them to contain red 

 blood, strongly contrasting with the dark blood issuing from the vena cava 

 below. In order to ascertain whether the same was the case with other 

 veins belonging to organs of secretion, he opened the vein of the sub-max- 

 illary gland of a dog, and found the blood of the darkest possible hue. At 

 that moment, however, the salivary secretion had stopped. In order to 

 excite it, a few drops of vinegar were introduced into the throat of the ani- 

 mal. The secretion recommenced, and after a few seconds the blood was 

 seen to change its color to the scarlet hue of arterial blood. As soon as the 

 secretion ceased, the blood resumed its former dark color. Hence M. Ber- 

 nard concludes that, although the name of red blood is correctly applied 

 to that of the arteries, that of black blood cannot be, with equal generality, 

 applied to that of veins ; for that in the veins of the organs of secretion 

 the color varies according as the organ is in a state of action or repose. 



WHEN IS A TISSUE DEAD. 



Some interesting experiments of M. Brown-Sequard have brought him to 

 this conclusion : That a tissue is not of necessity dead when it has lost its 

 vital properties or its natural action for a period of one or even several 

 hours ; and for the reason, that its properties and its actions may be restored 

 through the aid of blood charged with oxygen. 



ON THE PRODUCTION OF BONE. 



At a recent meeting of the French Academy, Dr. Olivier read a paper, in 

 which he endeavored to throw quite a new light on the production of bone. 

 The conclusions at which he arrived, if supported by future experimental- 

 ists, will not fail to produce a deep impression on the minds of physiolo- 

 gists ; while, at the same time, they will tend to enlarge and extend the 

 system of " anaplastie," as applied to surgery. The experiments of Dr. 

 Olivier were conducted entirely on rabbits of different a^es, and different 

 stages of growth, and were divided by him into three series. In the first 

 series, long slips of periosteum were detached from the tibia throughout its 

 entire length, one of the extremities only being left attached to the bone by 

 a peduncle; these slips of periosteum were then pushed along the muscles, 

 and twisted around them in a variety of ways. In the course of a certain 

 time osseous matter was produced, assuming the shapes of the twisted and 

 contorted membrane. In the second series of experiments, the slips of peri- 

 osteum which had been treated in the same manner as in the first series, 



