240 



SCIENCE 



[N. S. Vol. XLVII. No. 1210 



always obtained by dividing the sum of all 

 the positives except the highest by the highest, 

 e. g., 1/20 (18 + 8 + 1 + 0) =1.35. That a 

 mathematical treatment would improve and 

 standardize the computation can be seen from 

 the remark that a hasty study gives the follow- 

 ing simpler result (subject to the doubt al- 

 ready expressed as to the validity of the 

 theory) : The aggregate per cent, of " posi- 

 tive" tubes gives the logarithm of the most 

 probable average number of B. coli per 100 

 cc, e. g.j 1/20 (20 + 18 + 8 + 1 + 0) = 2.35, 

 and this is the logarithm of 224. This rule 

 will explain, for example, why Mr. "Wells's 

 "reversion method" works, for it is the 

 mathematical equivalent of the foregoing. 

 A further implication is that the author would 

 seem to be wrong in saying that the "per- 

 centage positive" (the aggregate percentage) 

 gives the desired result for a test using a 

 single dilution; to use a concrete example, 18 

 positives out of 20 at 1 cc. together with 

 positives out of 20 at .1 cc. should by any 

 test be regarded as indicating a smaller num- 

 ber of B. coli than the 18 positives alone, yet 

 the rule here commented on yields the same 

 results for both. 



It will be of undoubted value to have Mr. 

 Wells's more complete presentation particularly 

 of the experimental data which he mentions. 



W. D. CAffiNS 



Oberlin College, 

 Oberlin, Ohio 



SOME DEFECTS IN OUR AGRICULTURAL 

 INSTRUCTION 



In the preface to the text-book on agricul- 

 tural botany (" Traite de Botanique Agricole 

 et Industrielle ") by J. Vesque, professor of 

 agricultural botany in the National Institute 

 of Agronomy of France, the following criti- 

 cism on the agricultural instruction then 

 (1885) given in France occurs: 



In Fraace the agricultural instruction attaches 

 itself more and more to rearing of livestock. It 

 is too much forgotten that the animals are nour- 

 ished by the plants, or, if it is not forgotten, it is 

 taken for granted that the culture of plants con- 

 sists merely in the production of a maximum mass 

 of vegetables. The nature of the plants, the spe- 



cies which populate our fields, the seeds confined 

 to the soil are far from preoccupying the culti- 

 vator as much as the nature of the soil and the 

 fertilizers employed. All the agricultural in- 

 struction may at this point be summed up in three 

 words: Zooteohny, agricultural chemistry and 

 rural engineering. The plant, the initiative in all 

 agricultural pursuits, is almost excluded. How 

 many cultivators know the herbs of their farms, 

 how many are capable of distinguishing the good 

 from the bad? Liebig was certainly not wrong 

 in accusing the students of the agricultural schools 

 of knowing neither the seeds of the grasses nor 

 the grasses themselves. 



These remarks, describing the character of 

 the agricultural instruction in France in 

 1885, fit the condition prevailing in many of 

 our American agricultural colleges at the 

 present day to a strange degree of exactness. 

 The same neglect of the scientific knowledge 

 of plants is present, not only in courses in 

 which animal industry is the major subject, 

 but even in such courses as agronomy and 

 horticulture, which from their very nature 

 should deal largely with plants. We fiud the 

 botanical equipment of the average graduate 

 very meager indeed. He has not infrequently 

 been the recipient of long lecture courses on 

 forage plants without possessing definite 

 knowledge of the distinction between grasses 

 and legumes; or he has studied ornamentals 

 in his horticultural courses without enough 

 training in botany to appreciate either the 

 meaning of the description of a plant or the 

 importance of its scientific name; or he may 

 have spent considerable time in judging corn 

 without having clearly in his mind to which 

 family of plants the Indian corn belongs, or 

 what characteristics distinguish it from the 

 other members of its family. Such vague 

 knowledge of plants is not uncommonly met 

 with among graduates from agricultural col- 

 leges claiming thoroughness for their prepara- 

 tion. 



ISTo one will deny the right of agriculture to 

 the title of a generous place in the higher edu- 

 cation, based as it is on those natural sciences, 

 in which our country claims its proudest dis- 

 tinction in its progress. It is also undoubtedly 

 the intention of all these agricultural colleges. 



