664 



SCIENCE. 



[N. S. Vol. XXIII. No. 591. 



of blood to circulate there, it is lower 

 throughout the systemic circulation. 

 Paramecium Aurelia and Mutation: Gary N. 



Calkins. 



In March, 1905, a pair of conjugating 

 Paramecium caudatum was isolated from a 

 culture in an epidemic of conjugations. The 

 ex-conjugates had all of the characteristics of 

 P. aurelia. One died before many generations 

 in culture, the other is still living and is now 

 in the 346th generation. This one retained 

 the characteristics of P. aurelia until about 

 the 45th generation after conjugation, when 

 it lapsed again into the P. caudatum form, 

 with one micronucleus and other character- 

 istics of P. caudatum. The latter characters 

 are still maintained. 



The observation indicates one of two things. 

 Either, this is an interesting case of mutation 

 of species, with lapse into the parent form after 

 several generations, or the specific character- 

 istics are inadequate and P. caudatum and P. 

 aurelia are but variants of one species. The 

 latter is the more reasonable hypothesis, and 

 on grounds of priority the common forms of 

 Paramecium should be called Paramecium 

 aurelia. 

 Experiments with some Saline Purgatives 



given Sulcutaneously : John Auer. 



The author's experiments lead to the con- 

 clusions that the subcutaneous injection of 

 sodium sulfate and sodium phosphate does 

 not produce purgation in rabbits, and that 

 the pendular movements of the small intestine 

 are moderately increased. 



The Effects of Extra Stimuli upon the Heart 

 in the Several Stages of Block, together with 

 a Theory of Heart Bloch: Joseph Erlanger. 

 (Presented by S. J. Meltzer.) 

 The author's observations suggest the fol- 

 lowing theory of heart block: Clamping the 

 auriculo-ventricular bundle reduces the effi- 

 cieny of the cardiac impulses that reach the 

 ventricles. With a certain degree of pressure 

 the impulses become subminimal with respect 

 to the irritability of the ventricles. Such an 

 impulse would, therefore, fail to elicit a con- 

 traction of the ventricles. The next following 

 auricular impulse would be no stronger than 



the preceding one, but in the interval the 

 irritability of the ventricles has increased to 

 the extent that the weakened auricular im- 

 pulse now acts as an efficient stimulus. In 

 this state of affairs the rhythm would be 2:1. 

 A further reduction in the efficiency of the 

 auricular impulse would give higher degrees 

 of partial block and finally complete block. 

 With this theory as a basis it becomes possible 

 to explain all of the important phenomena of 

 heart-block. 



On the Nature of the Reflexes Controlling the 

 Successive Movements in the Mechanism of 

 Deglutition: S. J. Meltzer. 

 The experiments demonstrate that the func- 

 tion of deglutition is provided with two sets 

 of reflex mechanisms. One mechanism has 

 only one initial afferent impulse which travels 

 within the center independently of any fur- 

 ther aid from the esophagus; it is very sensi- 

 tive to anesthesia and may be called a higher 

 reflex. The other is a lower reflex, consisting 

 of a chain of local reflexes which are very re- 

 sistant to anesthesia. 



The Enzymes of Inflammatory Exudates. A 

 Study of the Enzymes concerned in In- 

 flammation and their Relations to Various 

 Types of Phagocytic Cells: Eugene L. 

 Opie. 



The phagocytic cells of an inflammatory 

 exudate contain two enzymes. One of these 

 ferments, characterized by its power to digest 

 protein in an alkaline medium, is contained 

 in the polynuclear leucocytes with fine granula- 

 tion, and since it is derived from the bone 

 marrow, may be designated myelo-protease. 

 The second ferment characterized by its power 

 to digest only in acid medium, in this respect 

 resembling the autolytic ferments of other 

 organs, is contained in the large mononuclear 

 cells of the exudate and is increased in lym- 

 phatic glands adjacent to the seat of inflam- 

 mation ; it may be designated lympho-protease. 

 Experimental Myocarditis. A Study of the 

 Histological Changes following Intravenous 

 Injections of Adrenalin: Eichard M. 

 Pearce. (Presented by Eugene L. Opie.) 

 The author gave many detailed results of an 

 elaborate study. He stated that there is little 



