ON THE COMPOSITION OF THE FUKUOKA CITY MARKET MILK. (IV). : (THE SEASONAL VARIA.TIONS OF THE PERCENTAGE OF LACTOSE AND FREEZING POINT DEPRESSION; THE RELA TION OF TOTAL SOLIDS TO LACTOSE, AND A COMPARISON OF THE SEASONAL VARIATIONS OF EACH OF TH E CHIEF CONSTITUENTS OF MILK)

1. The author had previously reported on the seasonal variations of the specific gravity, the percentages of total proteins and casein, and the relations of solids to proteins and to casein, and fat to proteins and to casein, in milk from the Fukuoka city market. This paper reports the results obtained in studying (I) the seasonal variations of the percentage of lactose and the freezing point depression, (II) the relation of total solids to lactose, and (III) the comparison of the seasonal variations of each of the chief constituents of milk in 3 samples of the morning\u27s whole milk (pasteurized) from the Fukuoka city market, taken over a period of one year from March 1937 to February 1938. 2. The record of seasonal variati o ns of the percentage of lactose for each month in 3 samples of the milk shows that the highest average percentage of lactose are found in July, May and June for samples No. 1, No. 2 and No. 3 respectively, and the lowest values in January, October and March. All samples reached a maximum in the summer, but 2 samples of the milk (No. 1 and No. 3) reached their minimum in the winter and the other sample (No. 2) in the autumn. A comparison of the results of these investigations with those carried out by LYTHGOE and SHERMAN on the monthly and four seasonal variations of the average percentage of lactose, shows different phenomena, in the various investigations, and these differences carry over, similarly, \u27 in the comparison of the other milk constituents; namely, fat, ash, total proteins and casein. The detailes of these varying phenomena are summarized in the following table : (snip). 3. The record of seasonal variations of the freezing point depression, in 3 samples of the milk, shows that the all samples reached a maximum in the summer, as was found to be true in the case of lactose, and the minimum value appeared in the spring. The record of seasonal variations of the freezing point depression for each month, in 3 samples of the milk, shows that the highest average freezing point depression of all samples was found in June, but the lowest average values occurred November (No. 1) and March (No. 2 and No. 3), this being in general similar to the facts found in the case of lactose. 4. According to LYTHGOE,t he relation between the total solids and the lactose, that is to say, the percentage of lactose in the solids is like that of the ash, the lactose being nearly constant and the percentage of lactose in the solids increasing as the solids decrease. The author\u27s results did not indicate such a relation between the total solids to the lactose. 5. The greater variation of each of the chief consti t u ents of milk was found in the fat, and the smaller variation was shown in the ash, hence the variations ranking may be shown as follows: (snip). 6. According to LYTHGOE, the seasonal variation of lactose is like that of ash, the lactose being nearly constant, but the author\u27s results shows that the seasonal variation of the percentage of lactose was greater than that for ash.1. 前回の調査の後をうけて昭和12年3月より昭和13年2月に亙る1ヶ年間に於ける福岡市市乳(1合壜詰滅菌全乳)(朝乳)3種の乳糖百分率及び氷點降下を檢定し, 是等2成分の(I) 季節的變化, (II)固形物と乳糖との關係並に(III)牛乳主要成分の季節的變化の比較に就いて檢討せんとするのである。2. 1ヶ年間を通じ月別に見たる福岡市市乳の乳糖百分率は第1號乳は7月, 第2號乳は5月第3號乳は6月に於て最高を示したのであるが最低は第1號乳は1月, 第2號乳は10月, 第3號乳は3月に於てこれを示した。而して今これを春夏, 秋, 冬の四季に分ちて見る時は市乳3種共に夏期に於て最高を示し最低は市乳2種(第1號乳及び第3號乳)は冬期に他の1種(第2號乳)は秋期に於てこれを示した。かくの如く福岡市市乳の乳糖百分率を1ヶ年を通じ月別に或は四季別に分ちて見る時及びの結果と比較し稍その趣を異にするを見る。尚この現象は他の牛乳組成分即ち脂肪, 灰分, 蛋白質及びカゼインの季節的變化とを比較するに之亦同樣にその趣を異にするを見る。今是等牛乳組成分の最高最低を示せる月を總括して表示すれば次の如くである。(省略) 3. 氷點降下は市乳3種共に夏期に於て最高を示し前記乳糖の場合と同一であるが最低は市乳3種共に春期に於てこれを示した。尚これを月別に見るときは市乳3種共に6月に於て最高を示し最低は第1號乳は11月, 第2號乳及び第3號乳共に3月に於てこれを示した。而してこの結果は大畿に於て乳糖の場合と相類似するを見る。4. LYTHGOE に從へば固形物と乳糖との關係即ち固形物100分中の乳糖量は次分と同樣に殆んど恆量を示し且つ固形物の減少に伴つて増加する。然るに著者の實驗結果はかゝる判然たる關係を見出すことが出來なかつた。5. 牛乳主要成分中季節に由つて影響せらるゝこと最も大なるものは脂肪でその最も小なるものは灰分である, 今そめ順位を示せぱ次の如くである。(省略) 6. LYTHGOE によれば乳糖の季節的變化は灰分と同樣に殆んど恆量を示す。然るに著者の實驗結果に於ては乳糖百分率の季節的變化は灰分よりも大である