The Poison of Yeilo-w Fever. 317 



covered with glycerin, to the wind. In this way Cunningham, at 

 Calcutta, collected particles of silica, amorphous granules, carbon, 

 lime, starch-grains, cells, hair, vegetable tissue, cotton-fibers, oil- 

 globules, pollen, spores of cryptogams and, occasionally, a few 

 bacteria. 



In speaking of the possible action of spores or living particles 

 so minute as to be overlooked with the microscope. Dr. Schmidt 

 maintains that the theory of contagium vivum is not founded 

 upon any assumption regarding invisible germs. We must, how- 

 ever, remind the reader that, although the true spores of minute 

 monads have been seen in mass by such careful observers as Drs. 

 Dallinger and Drysdale, these spores are so exceedingly minute 

 when first discharged, that they could not possibly be recognized, 

 or even found, after they are once scattered. When they issue 

 from the parent cell they are seen as a mere cloudiness, in which 

 it is almost, if not quite, impossible to distinguish the individual 

 particles, even w'ith the most perfect illumination and best optical 

 appliances. Therefore, the assumption of invisibly minute spores 

 would be quite consistent with facts of observation, viewed from 

 the stand-point of the germ theorist. 



The weight of evidence, as adduced by Dr. Schmidt, tends to 

 prove that the specific virus of yellow fever is a product of the 

 human body. The poison may exist in the gaseous form — its 

 presence is always indicated by a peculiar odor which emanates 

 from patients affected by the disease — and it may be carried long 

 distances in articles of clothing. An eminently contagious disease, 

 it can only be communicated from one person to another ; except 

 under very rare, but, at the same time, possible conditions, which 

 may lead to its spontaneous development in the system. It is ne- 

 cessary to assume that it had a spontaneous origin in some past time. 



It is a curious fact — not without a strong bearing upon the 

 views above set forth — that, as the virulent action of putrescent 

 blood is greatly intensified by passing through the bodies of 

 several animals in succession, so the activity of the yellow fever 

 poison seems to become greater as it passes from patient to pa- 

 tient, and the last persons attacked during an epidemic are likely 

 to have the disease in its most aggravated and dangerous form. 



If the cause of yellow fever is a glandular product, very simple 

 sanitary measures will suffice to prevent its spread. No means of 

 disinfection designed primarily to destroy living germs, will equal 

 in eflficiency perfect ventilation. The poison does not require to 



