HISTOLOGY (from Gk. laros, histos, web, from larcivat, histanai, to stand + -.2my1a, account. from NI-yetv, legein, to say). That branch of biological science which treats of the micro scopical structure of living organisms, both ani mal and vegetable. The histology of plants belongs to the domain of botany, that of animals to the domain of human and comparative anatomy. Just as gross anatomy is subdivided into normal anatomy and pathological anatomy, so histology may be subdivided into normal histology and pathological histolOgy. The term histology when unqualified is usually accepted as referring to normal histology.
His•onY. Although the study of the micro structure of plants and animals may be traced to the times of _Malpighi (1628-94), who d iscovered thus blood.•orpuseles. Robert llooke. \dm was the first (16671 to describe plant cells, and Lceuwen hock ( 1632-1723 ) , who, with conipa ra t ively imperfect optical means. prac tically laid the foundations of our knowledge of the minute structure of the tissues, no definite in histology as a seience was Made until the beginning of the nineteenth century, when t he emnpound microscope began to assume its pres ent improved form. The great work of Bichat, entitled .111‘110Illif ii lit rhyAi0 loyio et a la maducinc (ISOI ), marked an epoch in the development of the science of histology. Although he apparently did little actual work with the microscope. he brought to bear upon the aehievem•nts .4 other investigators the power of his generalizing mind, and was the first to clas sify tissues according to their structure. After Itichat Paine all epoch of histological research.
during whieh the microscopic observations of Malpighi and 1..veuwenhoek were extended in ac cordane• with the general system of Biehat. The next groat step forward was made by two botanists. lingo von Mold and Schleiden. discovered the cellular basis of all plant struc ture. The discovery of the method of combining lenses so as to render them achromatic gave a new impulse to the study of histology, and a more perfect classiticathm of the tissues of the body was the result, as it placed in the hands of Seh•ann an instrument which enabled him to demonstrate the law that all animal as well as plant tissues are eomposed of and develop from Schleiden had already demonstrated this. which may be called the greatest diseovery in histology. and therefore he and Schwalm are often called the flounders of the science of histogenesis, or the study of the origin of tissues. more re cently pursued with great by Reichert. Krdliker, Remak, and others. Then the micro scold.- anatomy of diseased structures and their mode of development calme to be investigated, and the scienve of pathological histology took its rise. Johannes Milner is regarded as the father of this branch of histology. as lie indicated the general direction in which the investigation of diseased growth: should lie pursued. Afterwards Virchow published his celebrated cellular Pathology, and later the scienee was still further enriched by the labors of Billroth. Rindtleisch, Von Reckling hausen, Cohnlwim, and others.
Ill sTotooy OF ANINIALs.