GENESIS OF INTERMEDIATE FORMS 
55 
cytic in function, are also found in small numbers in some typical lymph 
nodes ; and that, as far as microscopical appearances are concerned, there 
is a striking similarity between the sections of the latter and some of the 
specimens which simulate hemal nodes so closely in external and micro- 
scopical appearances. 
The Genesis of Intermediate Forms 
A moment's reflection will make it evident that any condition which 
results in congestion or hemorrhage or the accumulation of blood cells in 
the parenchyma or the sinuses of lymph nodes, will produce the speci- 
mens which have been responsible for much confusion. In fact many 
investigators frankly stated that they could not distinguish between con- 
gested or hemorrhagic lymph nodes and hemal nodes. Haberer [10], 
for example, stated that he repeatedly confused human lymph nodes 
which were changed by sepsis, with accessory spleens macro scopically 
although they were found to be typical lymph nodes microscopically. Ha- 
berer also called attention to the fact that in emaciated individuals nodes 
are frequenly found which do not look like spleens mrcroscopically be- 
cause they lack Malpighian corpuscles, but which seem to be transition 
forms resulting from pathological conditions. Moreover, it is probable 
that the changes observed in lymph nodes after splenectomy by many, if 
not all, the early experimenters, were of septic origin, as Foa and Schiff 
held, and as their own descriptions suggest. Besides, it is apparent that 
blood cells must be found in the sinuses of lymph nodes whenever the 
afferent lymphatics drain an area in which such cells can enter the lym- 
phatic vessels, as in the case of wounds, injuries, inflammations, etc. 
Retterer and Lelievre [23] also showed that stasis of the lymph current 
results in the accumlation of blood cells in lymph nodes. Hence these 
authors conclude that hemolymph nodes are only lymph nodes in which 
there is stagnation of the lymph current. Retterer [19], who called at« 
tention to the fact that "ten years since" — thirteen years — he reported the 
constant presence of erythrocytes in the lymph of the dog, rabbit, and 
guinea-pig, says Forgeot has shown the same for ruminants. Forgeot [6| 
also claimed to have found nodes in the lumbar region of sheep, goats, and 
under the pleura and pericardium in bovines, from which blindly-ending 
efferent lymphatics of various forms extended and occasionally returned 
to the node. Retterer [19] furthermore found that bleeding* and tem- 
porary abstinence removed the blood cells from hemolymph nodes and 
*Most investigators have held the contrary for bleeding. 
