144 Inheritance of Specific I so -agglutinins in Human Blood 



group of the serum, and stored in the dark. The action of light is said 

 to hasten the disappearance of the iso-agghitinin, which otherwise occurs 

 very slowly ; and serum prepared and kept in this way remains active, 

 in the writer's experience, for at least three months. 



When required for use the serum is transferred to sterile bottles, of 

 the type known to dispensing chemists as " nitric acid bottles " ; the 

 wooden cases provided with these protecting the serum from the action 

 of light. To each 5 cc. of the serum is added, as a preservative, three 

 drops of a O'l % solution of proflavine in physiological sodium chloride. 

 Flavine and its derivatives normally agglutinate washed red cells, but this 

 effect is absent when serum is present with the corpuscles. It is found 

 that proflavine in the proportion stated prevents the growth of bacteria 

 during the period the serum is in constant use, provided care be taken 

 to introduce only sterile appliances into the bottles. The disadvantage 

 of chloroform in small quantities as a preservative is that when the cells 

 to be tested are of weak agglutinophilic capacity, lysis may precede and 

 interfere with the observation of agglutination (cf Robertson, 1918). 



2. The performance of the test. A spirit lamp should be always 

 carried to cleanse the platinum loop with which the preparations are 

 made. Two clean slides, labelled 2 and 3 respectively, are used for each 

 test. Upon each is placed two loopfuls of the appropriate serum, care 

 being taken to cleanse the loop carefully in the flame before introducing 

 into the second bottle. The tip of a finger is cleansed with alcohol, and 

 pricked with a sterile needle. To the serum on each slide is added a 

 loopful of blood, and the preparation thoroughly mixed with the loop; 

 care being taken as before to cleanse the wire in the flame between 

 contact with different sera. By rocking the slides to and fro, agglutina- 

 tion if present is usually visible in a minute or two at room temperature. 

 Doubtful cases may be gently warmed, and rocked for ten minutes 

 before readings are taken. 



Two points of some practical importance may be here commented 

 upon. The use of hollow ground slides when performing the test in this 

 manner is to be avoided, since the red corpuscles may sink to the bottom 

 of the depression, and simulate a massive agglutination where none is 

 present. This is particularly liable to take place when the slide is 

 insufficiently rocked. 



Further, in about 25 °/^ of cases iso-haemolysin is found in a given 

 human blood serum in addition to iso-agglutinin. This factor however 

 does not interfere with the test, since, as Moss puts it, " all sera contain 

 an anti-haemolysin which protects the homologous corpuscles and those 



