28 Society for Experimental Biology and Medicine. 



The enzyme of the diplococcus acts energetically upon other 

 bacteria, bringing about their dissolution. It acts upon B. typhosus, 

 B. coli communis, B. pyocyaneus, B. anthracis, M. catarrhalis, and 

 to a less degree and more slowly upon Staphylococcus aureus. 



(25) 168 



On the supposed existence of efferent fibers from the diabetic 

 center to the liver. 



By J. J. R. MACLEOD and 0. E. BRIGGS. 



[From the Physiological Laboratory, Western Reserve University '.] 



To explain the causation of those forms of glycosuria which 

 follow stimulation of the central end of sensory nerves and piqure 

 of the medulla, it is commonly believed that there is a diabetic 

 center in the medulla from which efferent impulses are transmitted 

 to the liver causing the glycogen in this organ to become so rapidly 

 converted into dextrose that hyperglycemia and glycosuria follow. 

 Since section of the vagi does not prevent these forms of glycosuria, 

 it is thought that the efferent impulses travel by the upper portion 

 of the spinal cord and the greater splanchnic nerves. 



That increased production of dextrose by the liver is the imme- 

 diate cause of the glycosuria, there is no doubt, but the evidence 

 that it is by nervous impulses transmitted from the medulla to the 

 liver along the above path that this hyperglycogenesis occurs is 

 very meager. 



The evidence in favor of such a view is as follows : 



1. Puncture of the floor of the fourth ventricle does not cause 

 glycosuria if the splanchnic (greater) nerves, or the upper thoracic 

 spinal nerves, or the spinal cord above the first thoracic nerves be 

 cut (Eckhard, Marc Laffont, etc.). 



2. Irritation of the cervical spinal cord, or of the upper thoracic 

 sympathetic ganglia causes glycosuria (Pavy, Schift). 



Against such a view stands the fact that stimulation of the 

 splanchnic nerves does not cause glycosuria (Cf. Pfliiger). 



As has been shown by us, and by other workers, the reducing 

 power of the urine of dogs is, within certain limits, no index of 

 the amount of sugar in the blood. Now, very little of the above 



