THE DETECTION OF PREGNANCY 



Under normal conditions, the substances entering the blood 

 stream, apart from the fats, are presumably the simple products 

 fashioned during digestion from the complex materials taken as 

 food ; they are either rebuilt into various tissues or gradually 

 utilised as sources of energy ; and in the latter case are finally 

 resolved almost entirely into carbon dioxide, ammonia and 

 water. 



Under the conditions of disease, more complex substances 

 may enter into circulation or the blood may become more or less 

 infected with micro-organisms. It is all-important to determine 

 what are the agencies at the disposal of the animal organism 

 whereby such intrusions are countered and rendered ineffective. 



The body cells generally undoubtedly contain enzymes 

 capable of acting on albuminous materials, on carbohydrates 

 and on fats ; these are set free when the cells are subjected to 

 the action of hormones or to mechanical disruption. But fresh 

 blood plasma and serum, in the case of most animals, appear 

 to be without hydrolytic power. 



Prof. Abderhalden, who has been an active worker in this 

 field of late years, has recently published an interesting account 

 of his views and experiments in book form. 1 



Observations have been carried out by injecting various 

 hydrolytes and after an interval observing the action of the 

 blood plasma or serum on the hydrolyte, normal plasma or 

 serum having been found to be without action. To ascertain 

 whether an effect had been produced, serum from the treated 

 animal was mixed with a -solution of the hydrolyte and the 

 change in optical rotatory power which took place over an 

 interval of several hours was followed by means of the polari- 

 meter. A specially constructed short tube was used in carrying 

 out the observations, so as to permit of the use of small 

 quantities of material. 



1 Schntzfermente des tierischen Orgafiismics. Ein Beitrag zur Kenntnis der 

 Abwehrmassregeln des tierischen Organismus gegen korper-, blut- und zellfremde 

 Stoffe. Von Emil Abderhalden. (Berlin : Julius Springer, 191 2 [pp. xii + 110.) 



472 



