BLOOD AND LYMPH 259 







has, however, made such a differentiation possible. This test, known as 

 the Bordet reaction, is founded upon the fact that the blood serum of an 

 animal into which has been injected the blood of another animal of 

 different species develops the property of agglutinating and dissolving 

 erythrocytes similar to those injected, but exerts this influence upon 

 the blood from no other species. The antiserum used in this test is 

 prepared by injecting rabbits with 5-10 c.c. of human defibrinated 

 blood, at intervals of about four days, until a total of between 50 and 80 

 c.c. has been injected. After a lapse of one or two weeks the animal is 

 bled, the serum collected, placed in sterile tubes and preserved for use as 

 needed. In examining any specific solution for human blood it is simply 

 necessary to combine the antiserum and the solution under examination 

 in the proportion of 1:100 and place the mixture at 37C. If human 

 blood is present in the solution a turbidity will be noted and this will 

 change within three hours to a distinctly flocculent precipitate. This 

 antiserum will react thus with no other known substance. 



Lymph may be considered as the "middle man" in the transactions 

 between blood and tissues. It is the medium by which the nutritive 

 material and oxygen transported by the blood for the tissues is brought 

 into intimate contact with those tissues and thus utilized. In the 

 further fulfillment of its function, the lymph bears from the tissues 

 water, salts and the products of the activity and catabolism of the 

 tissues and passes these into the blood. Lymph, therefore, exercises 

 the function of a "go-between" for blood and tissues. It bathes every 

 active tissue of the animal body, and is believed to have its origin partly 

 in the blood and partly in the tissues. 



In chemical characteristics, lymph resembles blood plasma. In fact, 

 it has been termed "blood without its red corpuscles." Lymph from 

 the thoracic duct of a fasting animal or from a large lymphatic vessel of 

 a well-nourished animal is of a variable color (colorless, yellowish or 

 slightly reddish) and alkaline in reaction to litmus. It contains 

 fibrinogen, fibrin-ferment and leucocytes and coagulates slowly, the clot 

 being less firm and bulky than the blood clot. Serum albumin and 

 serum globulin are both present in lymph, the albumin predominating 

 in a ratio of about 3 or 4:1. The principal inorganic salts are sodium 

 salts (chloride and carbonate), whereas the phosphates of potassium, 

 calcium, magnesium and iron are present in smaller amount. 



Substances which stimulate the flow of lymph are termed lympha- 

 giigues. Such substances as sugar, urea, certain salts (especially 

 sodium chloride), peptone, egg albumin, extracts of dogs' liver and 

 intestine, crab muscles and blood leeches are included in this class. 



In a fasting animal, the lymph coming from the intestine is a clear, 



