November 18, 1922] 



NA TURE 



659 



subject and may be thoroughly recommended to all 

 who wish for a critical statement of the problems which 

 are attracting so much attention at the present time. 

 It is to be hoped that those of us who have been misled 

 by the wild reports of marvellous results published in 

 the Press will adopt Dr. Harrow's cautious attitude 

 and assess such reports at their proper value. Prof. 

 Harvey Cushing, as quoted by Dr. Harrow, remarks : 



" Nothing will discredit the subject so effectively as 

 pseudo-scientific reports which find their way into 

 advertising leaflets, where, cleverly intermixed with 

 abstracts from researches of actual value, the adminis- 

 tration of pluriglandular compounds is promiscuously 

 advocated for a multitude of symptoms, real and 

 fictitious. The Lewis Carroll of to-day would have 

 Alice nibble from a pituitary mushroom in her left hand 

 and a lutein one in her right hand and presto ! She 

 is any height desired ! " 



The title of Dr. Harrow's book, and also to a lesser 

 degree that of Prof. Vincent's, invites some criticism. 

 The name " gland " implies to the physiologist many 

 organs and tissues which have functions other than 

 that of producing substances for the purpose of exerting 

 a particular action on other organs or tissues when they 

 pass into the blood current. Those which form saliva 

 and also the lymphatic glands may be mentioned. It is 

 true that we might define a gland in a new way and 

 say that any organ that produces some substance not 

 already contained in the blood is entitled to the name. 

 It would conduce to accuracy, however, if the name 

 " gland " were limited to those organs able to pour 

 out a secretion which can be collected and examined — 

 those of " external secretion " in fact. In this case, 

 the ductless " glands " would have to be called 

 " bodies," or some similar name, as is indeed frequently 

 done in speaking of the " pituitary body " or the 

 " supra-renal bodies." The name " secretion " itself 

 as applied to the activity of the endocrine organs is also 

 not very satisfactory. 



It must be confessed that we do not possess a really 

 good name for these substances which act as " chemical 

 messengers," formed by special cells for the special 

 purpose, if the expression may be allowed, of produc- 

 ing an effect on another organ or cell when carried to 

 it by the blood. A short word with the meaning of 

 " chemical messenger " is what is wanted. When 

 Prof. Starling and the present reviewer were engaged 

 in investigating the mechanism of pancreatic secretion, 

 we sought in vain for a word of this kind and were 

 finally obliged to be satisfied with " hormone," although 

 we felt that it was not exactly what we wished. It has, 

 however, come into general use, although its meaning 

 as " setting into activity " has caused the introduction 

 of a number of other names, which might perhaps have 

 been avoided. It is to be remembered that a messenger 

 NO. 2768, VOL. I IO] 



is sent for a special purpose, although he must take the 

 road or railway which is in existence. Thus one of our 

 hormones in the blood passes by a number of different 

 cells before arriving at that kind which is sensitive to it, 

 just as a letter sent by post is only received at that 

 house to which it is addressed. A definition on the 

 lines suggested would exclude such a constituent of the 

 blood as carbon dioxide, called by Gley a " par- 

 hormone." Carbon dioxide would be produced by all 

 active cells whether the respiratory centre happened to 

 be sensitive to it or not. A train (the blood) carrying 

 soldiers (carbon dioxide) to a port for foreign service 

 (the outer air) might pick up men at various stations 

 (organs of the body) through which it passed. At one 

 station there might be on the platform a nursemaid (the 

 respiratory centre) who greatly admired soldiers. She 

 would be excited by the passage of the train, but it 

 would scarcely be held that the soldiers were sent for that 

 purpose. The development of the special sensibility 

 of the respiratory centre is of course another question. 



While each of the books before us is provided with 

 a good index, Dr. Harrow alone gives a list of original 

 works, which, however, does not profess to contain more 

 than the most important ones. Considering that Prof. 

 Vincent's book is especially valuable for reference, it 

 seems unfortunate that he has omitted in this second 

 edition the bibliography contained in the first. It may 

 be putting too great a burden upon him, but it would 

 have been of great service if he had given the titles of 

 papers which seemed to him to contain definite new 

 knowledge, rejecting those numerous ones which have 

 no real value. Perhaps we might ask him to reprint 

 in the next edition the original bibliography, adding to 

 it papers which appeared up to 1915 and referring to 

 Physiological Abstracts for the subsequent literature. 

 Although many of the current text-books of physiology 

 serve well for the use of junior students without 

 references, it must not be forgotten that the more 

 advanced of these books are often referred to by 

 research workers and teachers, and information as to 

 the place of more detailed description would greatly 

 increase their value. 



The great difficulty of exact research in the problems 

 dealt with is impressed upon readers of either of the 

 books before us. Sensational reports as to the trans- 

 plantation of organs from one individual to another, or 

 even from one species to a different one, are put in their 

 proper place. It seems certain that individual char- 

 acters are so highly marked, at all events in the higher 

 mammals, that the only permanent grafting occurs 

 when a tissue is taken from one part of an individual 

 and planted in another part of the same individual. 

 Occasional success has been obtained by L. Loeb 

 between closely related persons, brothers for example. 



