260 ARI^HUR WILLIAM MEYER 



nodes, following various influences, have, of course, long been 

 recognized but the nodes remain what they are — lymph nodes — 

 and are not thereby converted into something else — hemal nodes 

 having no connection with the lymphatic system. 



It can be urged against these experiments on guinea-pigs that 

 the injections were not continued over a sufficiently long period 

 and that hemal nodes may have failed to form for this reason. 

 Fortunately through the courtesy of my colleague. Professor 

 Zinsser, I was able to examine the carcass of a goat which had 

 been immunized against typhoid nine months before death and 

 which had also been bled repeatedly. Yet only several small 

 hemal nodes were found. Since all other goats examined during' 

 the past years contained more hemal nodes than this animal 

 which had receiyed repeated injections of toxin-containing mate- 

 rial and had also suffered repeated losses of blood, it is evident 

 that neither of these things resulted in the production of hemal 

 nodes. Through similar courtesy I was also enabled to examine 

 the carcasses of two sheep, one of which, although only about 

 three years old, had been bled from 5 to 125 cc. approximately 

 a hundred times during a period of two years. The other had 

 been bled forty times during a year. In spite of this repeated 

 loss of blood these animals were very fat indeed. Yet upon 

 examination all lymph nodes were found to be exceptionally pale 

 and small and only about a score of small apparently hemal nodes^ 

 from 1.5 to 2.5 mm. in size were found in the fat about the 

 superior mesenteric vein in the first sheep and six in the second. 

 In the first sheep, none were present in the very large amount 

 of fat in the lumbar prevertebral region where they are usually 

 so numerous, and only five (2-3 mm.) in the second. From these 

 things it is evident, of course, that the injection of toxin or the 

 loss of blood, even if repeated and extending over long periods, 

 do not cause the formation of hemal nodes or necessarily pro- 

 duce any marked permanent macroscopic changes in lymph nodes. 

 That these things may evoke a transient reaction on part of the 

 lymph nodes is probable, to be sure, but that does not justify 



* These were too small for puncture injections. 



