Letters 195 



LETTER VI 



To John Daniel Horst, principal Physician of 

 Hesse- Da rmstadt 



EXCELLENT SIR, I am much pleased to find, that 

 in spite of the long time that has passed, and the dis- 

 tance that separates us, you have not yet lost me from 

 your memory, and I could wish that it lay in my power 

 to answer all your inquiries. But, indeed, my age does 

 not permit me to have this pleasure, for I am not only 

 far stricken in years, but am afflicted with more and 

 more indifferent health. With regard to the opinions 

 of Riolanus, and his decision as to the circulation of 

 the blood, it is very obvious that he makes vast throes 

 in the production of vast trifles ; nor do I see that he 

 has as yet satisfied a single individual with his figments. 

 Slegel wrote well and modestly, and, had the fates 

 allowed, would undoubtedly have answered his argu- 

 ments and reproaches also. But Slegel as I learn, and 

 grieve to learn, died some months ago. As to what 

 you ask of me, in reference to the so-called lacteal 

 veins and thoracic ducts, I reply, that it requires good 

 eyes, and a mind free from other anxieties, to come to 

 any definite conclusion in regard to these extremely 

 minute vessels; to me, however, as I have just said, 

 neither of these requisites is given. About two years 

 ago, when asked my opinion on the same subject, I 

 replied at length, and to the effect that it was.,not 

 sufficiently determined whether it was chyle or one of 

 the thicker constituents of milk, destined speedily to 

 pass into fat, which flowed in these white vessels ; and 

 further that the vessels themselves are wanting in several 

 animals, namely, birds and fishes, though it seems most 

 probable that these creatures are nourished upon the 

 same principles as quadrupeds ; nor can any sufficient 

 reason be rendered why in the embryo all nutriment, 



