30 The Cytotoxins of Blood Serum 



Venom intermediary body, added to blood corpuscles, had no effect 



and serum complement gave 



haemolysis. 

 Serum complement alone had no effect. 



This result is comparable to what has been observed with regard to the non- 

 haemolytic action of blood serum from normal animals upon the washed corpuscles 

 of certain other species, and directly supports a contention of Friedenthal's (men- 

 tioned later), that tests made with normal sera upon the washed corpuscles of other 

 animals do not afford a means of studying blood relationships with haemolysins. 



The importance of a further study of the complement is well shown by the 

 investigations of Moro (31, x. 1901) upon serum, and its bactericidal properties 

 under different conditions. Using the methods devised by me (1888), but express- 

 ing the bactericidal effect in terms of per cent, of bacteria destroyed by contact 

 with the serum, he found that fresh 



Placental blood serum killed 58-9 / 



Older children's 46-3% 



Bottle-fed infant's 33-4/ 



Breast-fed 77-0 ',, 



An experiment conducted upon a single infant gave : 



Placental blood of mother killed 56-0% 



Breast-fed infant 2 weeks old, its serum killed 72'9/o 



Serum of the same child after bottle-feeding for 2 weeks killed 407%. 



The blood serum of a breast-fed child had more haemolytic action on rabbit 

 corpuscles than did that of a bottle-fed infant's ; even the sickliest breast-fed infant 

 had more bactericidal substance in its serum than the healthiest bottle-fed infant. 

 The serum of a new-born infant only killed 59 % of the bacteria. 



That a fundamental interest attaches to the ferment-like complements in 

 relation to normal physiological processes is moreover very clear from a sug- 

 gestive paper by Wassermann (1, I. 1903), whose investigations were stimulated 

 by those of Moro just quoted. It is a well-established fact that breast-fed infants 

 thrive as a rule better than those fed upon cows' milk. Heubner, using Rubner's 

 method, has studied the process of assimilation in such children comparatively, and 

 found that, reckoned in calories, the child receiving mother's milk showed the most 

 growth ; in other words, that homologous mother's milk achieves as much with a 

 few calories as does cow's milk with a very large number of calories. The infant fed 

 on cow's milk has to expend energy in the form of glandular and digestive activity 

 to assimilate the heterologous milk. That there is such an increased activity is 

 evident from the following. 



If heterologous food-stufts, such as goat serum, etc., are injected, say into a 

 guinea-pig's peritoneum, the peritoneal exudation is capable, soon after, of destroying 

 and dissolving large numbers of bacteria (B. typhosus), whereas the contrary is 

 the case in a normal animal. The peritoneal exudation in the serum-treated 

 guinea-pig is rich in digestive complements which have appeared for the purpose 

 of acting upon the serum injected, and it is these digestive substances (complements) 

 which destroy the bacteria. 



