THE BLOOD AND THE LYMPH. 701 



are eminently adapted for such investigations, in the mesentery, and 

 before it reaches the lymphatic glands, the chyle contains but few, and 

 in the smallest mesenteric vessels which allow of being examined, fre- 

 quently even no chyle-corpuscles at all. Where they do exist, which 

 is always the case in the larger trunks, they usually appear small 

 (0-002-0-003 of a line), closely investing the minute nucleus, and often 

 even, as it were, in process of formation by the apposition of granules. 

 As the chyle traverses the mesenteric glands, the cells become more 

 and more numerous and larger, so that in the lacteals at the root of 

 the mesentery (and also in the larger lymphatic trunks), together with 

 the small cells which are still present, we find numerous larger ones, up 

 to 0-0055 of a line in size. At the same time, at any rate in the Dog, 

 Cat, and Rabbit, a multiplication of the lymph-corpuscles by division 

 takes place more or less actively ; in this process the larger cells elon- 

 gate till they attain a length of 0*006-0-008 of a line, and when the 

 nucleus has divided, are separated into two by a median, circular con- 

 striction. This proceeding does not usually occur at all in the thoracic 

 duct, and consequently the larger cell-forms, of 0-004-0-0055 of a line 

 are here rare. In Animals, at all events, the majority of the cells in 

 this situation are larger than the blood-corpuscles, that is to say, they 

 are 0*0025-0-0035 of a line, whilst in Man, at least as observed by 

 Virchow and myself in an executed criminal, they were invariably 

 smaller (from 0*002 of a line on the average). The nuclei of these 

 lymph-corpuscles, which are imperceptible without the addition of acetic 

 acid, were for the most part single and round, occasionally, also, horse- 

 shoe shaped, or constricted in t.he middle, very rarely truly multiple. 

 In other Mammalia, cells having nuclei disintegrated by acetic acid, or 

 naturally constricted and multiple (3-5 fold) are very rare, omitting 

 those in process of division ; although occasionally such occur even in 

 considerable quantity. 



Red Hood-corpuscles I have not as yet noticed in the human chyle, 

 when it has been carefully taken, and under normal conditions ; whilst 

 in animals these corpuscles almost always occur in the thoracic duct in 

 small quantity, and also frequently in the lymph of certain organs, as 

 of the spleen. As they do not exhibit the slightest trace of a develop- 

 ment within the lymphatics, I regard them as elements escaped from 

 the bloodvessels, and indeed, am of opiriion, so long as direct connec- 

 tions between the two sets of vessels in the peripheral parts are not 

 shown to exist, that this passage is an accidental occurrence, from the 

 rupture of finer vessels, which, owing to the peculiar structure of cer- 

 tain organs, as the spleen and lymphatic glands, may be very readily 

 conceived ; and, indeed, as I have shown in the Tadpole, may be 

 directly observed. I would, however, remark, that I have not unfre- 

 quently met with brown, round granule cells, 0-004-0-005 of a line in 



