Effect of Saliva on Coagulation of the Blood

Abstract

It was observed that the addition of human saliva to dog blood greatly shortened the coagulation time. Hunter 1 alone observed that the addition of his own saliva to his own blood hastened the coagulation. He did not try to determine the nature of the active substance. There is nothing specific about this material. Saliva hastened the coagulation of the following types of blood: (1) Other humans; (2) recalcified oxalated human blood of another individual; (3) dog blood; (4) recalcified oxalated ox blood; (5) recalcified oxalated ox plasma. Figures for dog blood are given below.

Human saliva was obtained from various individuals after rinsing the mouth with warm physiological saline and discarding the first samples. Salivary flow was increased by chewing paraffin. All samples of saliva were centrifuged for 30 minutes before using. Unless otherwise indicated, the saliva was unheated. When heated, the saliva was placed on a water bath for 20 to 45 minutes and then diluted to its original volume, cooled to room temperature, and filtered before using. Blood was obtained directly from the cannulated femoral artery of dogs into tubes containing the known amount of saliva. Four to 8 samples were used for each determination; the times given below are averages. The saliva and tubes were at room temperature. The times for coagulation are given in minutes and seconds.

It will be seen that a reduction of 80% in clotting time can be obtained with proper proportions. Experiments in which saliva was added to blood in proportions of 1:400 showed a decreased coagulation time. When the proportion of saliva to blood is very great, such as 20:1, the coagulation time is still reduced, but not very much. Similar reductions in clotting time were observed in the case of the other types mentioned above.