1062 Tbaxsactwxs of the Ameiucax Ixstitvte. 



Malaria. 

 Dr. P. II. Yandervvejde spoke on the subject of malaria, and 

 sliowcd how the microscope was used in investigating tliis matter by 

 exhibiting those instruments, with several appliances of liis own 

 invention. He said he brought the microscope here to sliow what 

 was the sheet-anchor of our hopes in acquiring knowledge on this 

 subject. It reveals to us the secrets of malaria. Tliis arrangement 

 of the microscope exhibited the most convenient way in which solid 

 and liquid substances are investigated. Here we have a device in 

 whicli is some blood taken from a person who died of the yellow 

 fever ; and here is another, filled with blood from cattle wdio have 

 died of the plague, in Texas, which is nothing but the yellow fever 

 in cattle. Tiiese are shown only to illustrate how modern appliances 

 are brought to bear on the microscope. Forty years ago the itch 

 insect was not known ; and even after it was discovered, it was some 

 time before it was accepted as an insect disease, and tliere is no doubt 

 but in time all malaria will be found to be of animal or vegetable 

 growth. The most recent investigations made on this subject are by 

 Dr. Ilarria, of Vienna. Dr. Ilarrist, of the Board of Health in this 

 city, sent to Dr. Ilarria, the bile of cattle that die<l of the plague in 

 Texas. After examination he found that this bile contained cells 

 teeming with animal life, and that these cells would multiply, and 

 that on the way to Vienna they had developed rapidly ; but when 

 nourishment was given them they increased very fast. (The Doctor 

 exhibited a drawing of these animals.) After being placed in saccha- 

 rine matter for one hour, they have all the qualities of the yeast 

 plant. When fermentation takes place there is always the yeast 

 jDlant with it. The yeast plant grows on decaying matter. Doctor 

 Harria's investigations led him to the conclusion that there was not 

 the least doubt but that the cause of the cattle disease was nothing 

 but animal growth, which lived at the expense of the blood, and 

 which disorganized the whole system, and in that way caused the 

 disease of the cattle. He made some further discoveries and very 

 curious ones too. There is a plant wliich is found in the conta- 

 gions matter of syphilis, and this he found in the highest devel- 

 opment of yellow fever. These investigations, apart from their 

 usefulness, purely ccuisidered in a scientific way, will throw 

 much light on spontaneous development. They will show that 

 many things are but modifications of others, though now they 

 may appear to be entirely dcstinct. Ti\c parasite of dogs, 



