RELATION TO OTHER SCIENCES 129 



disease in pigs and other animals to that in man; malaria and the 

 role which anopheles play therein; the recent investigations on the 

 conveyance of plague and other infectious diseases by animals. 

 Names of physicians like Kiichenmeister, 1 Davaine, 2 and others 

 have given human parasites their final place in zoology. I wish also 

 to call attention to the very recent investigations concerning pro- 

 tozoa as disease-producers, one of the most burning questions of 

 modern pathology, a question of extreme importance, and also of 

 correspondingly great difficulty. Unfortunately, investigations on 

 the parasitic protozoa remain still in their infancy, but even on this 

 question the pathologists of Europe and North America may demand 

 recognition of their zealous work. 



Closest and most numerous are, of course, the relations of patho- 

 logy to anatomy and physiology. Just as the study of the normal, 

 typic man is divided into anatomy and pathology with physiologic 

 chemistry, so also is pathology (apart from etiology andpathogenesis) 

 made up of pathologic anatomy and pathologic physiology with 

 pathologic chemistry. Just as health and disease pass imperceptibly 

 into one another, so there can be no sharp line drawn between patho- 

 logic and normal anatomy, normal and pathologic physiology. These 

 studies are not different sciences, but branches of the same scientific 

 tree with the same stem, the same roots. Their methods of investi- 

 gation are mainly the same. Discoveries in one generally mean 

 progress in the others. 



The time is not long past when instruction in pathologic anatomy 

 in our universities was in the hands of the professor of normal 

 anatomy, and when men like Joh. Fr. Meckel, Johannes M tiller, 

 and others enriched and fostered normal as well as pathologic ana- 

 tomy. Pathologic anatomy is only conceivable on a basis of normal 

 anatomy, and a glance at the history of medicine shows how every 

 progress in normal anatomy has produced an increase in the know- 

 ledge of pathologic anatomy. Only the flourishing of anatomy in the 

 sixteenth century made the development of pathology to a separate 

 science during the ensuing century possible. But here also pathology 

 was not only the receiving but frequently the producing science. 

 Pathologists not only enriched anatomic and histologic methods, 

 but contributed largely to the development of accurate anatomy, 

 the general as well as the special. Who does not think in connection 

 with "general anatomy" of Rudolph Virchow, 3 the man who coined 

 the famous words "omnis cellula e cellula" corresponding to Harvey's 

 "omne vivum ex ovo?" That saying while resting in great part on 



1 Kiichenmeister, Die in und an d. Korper d. lebend. Menschen vorkommen- 

 den Parasiten, 1878, 1879, 3. Aufl. 



2 Davaine, Traite des Entozoaires, Paris, 1877, 2. Aufl. 



3 Die Cellular pathologie in Hirer Begriindung auf physiologische und patho- 

 logische Gewebekhre, 1. Aufl. 1858; 4. Aufl. 1871. 



