261 
in distinguishing between hemal nodes and supernumerary spleens 
because neither is ever in connection with the lymphatic system after 
the manner of lymph nodes. v. SCHUMACHER (26) has raised certain ob- 
jections against the value and validity of the injection method as a 
means of differentiation between lymph and hemal nodes and against 
the latter being organs sui generis. Since, however, these observations 
and objections are not of real importance in connection with the 
question under consideration. They will be discussed fully in the writer’s 
articles on the hemal nodes of sheep upon which animal v. ScHUMACHER’S 
observations and conclusions were based. 
The animals upon which the following conclusions are based 
included 98 dogs, 59 cats, and approximately a dozen each of rabbits, 
rats (Mus norwegicus albinus) and guinea pigs. A number of mice 
and two wood rats (Neotoma fuscides) were also examined but the 
number was perhaps too small to be of any special value. 
In this series of dogs which ranged in age from the newborn to 
seven years, nodes which varied in color from pink to blood red were 
frequently found in different regions. Injections into these nodes 
under proper precaution always showed them to be in connection 
with the lymphatic system. This was the case even when they were 
found in locations in which lymph nodes usually are absent and when 
they were very seldom exceedingly small (1/.—2 mm) as was the 
case with by far the greater number of supernumerary spleens. It 
was also noticed that red lymph nodes were quite common in dogs 
which had been used for experimental purposes necessitating incisions. 
In a dog obtained through the courtesy of my colleague, Professor 
CRAWFORD, for example, in which a left femoral incision approximately 
five centimeters long had been made a few hours before death, several 
very red lymph nodes 4—5 mm in size, were found in the lumbar 
region. The large efferent lymphatic leaving these nodes was about 
3 mm in calibre and so dilated with blood-colored fluid that the 
valves stood out very plainly. As this trunk was traced centrally it 
was also noticed that the pink color became progressively paler. Upon 
injecting these reddened nodes in the lumbar region and also some 
in the meso-rectum, in serial order beginning with the most caudal, 
each successive node was easily filled with India ink and the blood- 
colored fluid forced centrally. Clamping the efferent vessel only lead 
to rupture of the node, not to injection of the veins. Hence even if 
the absorption of blood from the femoral incision was not responsible 
